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  • 101.
    Erdal, Nejla B.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Adolfsson, Karin H.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    De Lima, Sara
    Karolinska Inst, St Erik Eye Hosp, Div Ophthalmol & Vis, Dept Clin Neurosci, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    In vitro and in vivo effects of ophthalmic solutions on silicone hydrogel bandage lens material Senofilcon A2018Ingår i: Clinical and experimental optometry, ISSN 0816-4622, E-ISSN 1444-0938, Vol. 101, nr 3, s. 354-362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Acuvue Oasys silicone hydrogel contact lenses (Senofilcon A) are used as bandage lenses and often combined with ophthalmic solutions in the treatment of ocular diseases. Concerns have been raised regarding the compatibility and effect of eye-drop solutions on the bandage lenses, which have led to frequent replacement of lenses causing clinical problems. Some patients experience pain or discomfort during treatments and the accumulation of drugs and preservatives in lenses has been suggested as a possible reason. The aim with this study was to investigate the effect of ophthalmic solutions on silicone hydrogel bandage lens material Senofilcon A in vitro and in vivo. Methods: The effect of three common ophthalmic solutions Isopto-Maxidex, Timosan and Oftaquix on Acuvue Oasys (Senofilcon A) bandage lenses was evaluated. An in vitro model method was developed where drug and preservative uptake by Acuvue Oasys was monitored with ultraviolet-visible spectroscopy and laser desorption ionisation mass spectrometry. Surface morphology changes of the lenses were evaluated using scanning electron microscopy. The method was then implemented for the in vivo pilot study evaluating lenses worn by patients. Results: In vitro model study monitoring the drug and preservatives uptake showed that the active ingredients from all the eye drops together with preservatives were taken up by the lenses in significant amounts. For the in vivo study no traces of active ingredients or preservatives could be found on the worn and treated lenses regardless of time being worn or dosage profiles. The surface morphology changes in the in vivo study were also minor in contrast to the changes observed in the in vitro scanning electron microscopy images. Conclusion: The in vivo results demonstrate minor effects of the ophthalmic solutions on the worn lenses. These results do not support the building up of preservatives and drugs on the contact lenses as the cause of pain or discomfort experienced by some patients, which is encouraging for the use of bandage lenses in combination with ophthalmic solutions.

  • 102.
    Erdal, Nejla B.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Construction of Bioactive and Reinforced Bioresorbable Nanocomposites by Reduced Nano-Graphene Oxide Carbon Dots2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 3, s. 1074-1081Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioactive and reinforced poly(ϵ-caprolactone) (PCL) films were constructed by incorporation of cellulose derived reduced nanographene oxide (r-nGO) carbon nanodots. Two different microwave-assisted reduction routes in superheated water were utilized to obtain r-nGO and r-nGO-CA. For the latter, a green reducing agent caffeic acid (CA), was incorporated in the reduction process. The materials were extruded and compression molded to obtain proper dispersion of the carbon nanodots in the polymer matrix. FTIR results revealed favorable interactions between r-nGO-CA and PCL that improved the dispersion of r-nGO-CA. r-nGO, and r-nGO-CA endorsed PCL with several advantageous functionalities including improved storage modulus and creep resistance. The considerable increase in storage modulus demonstrated that the carbon nanodots had a significant reinforcing effect on PCL. The PCL films with r-nGO-CA were also evaluated for their osteobioactivity and cytocompatibility. Bioactivity was demonstrated by formation of hydroxyapatite (HA) minerals on the surface of r-nGO-CA loaded nanocomposites. At the same time, the good cytocompatibility of PCL was retained as illustrated by the good cell viability to MG63 osteoblast-like cells giving promise for bone tissue engineering applications.

  • 103.
    Erdal, Nejla B.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Yao, Jenevieve G.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cellulose-Derived Nanographene Oxide Surface-Functionalized Three-Dimensional Scaffolds with Drug Delivery Capability2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 2, s. 738-749Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multifunctional three-dimensional (3D) scaffolds were targeted by surface grafting cellulose-derived nanographene oxide (nGO) on the surface of porous poly(epsilon-caprolactone) (PCL) scaffolds. nGO was derived from cellulose by microwave-assisted carbonization process and covalently grafted onto aminolyzed PCL scaffolds through an aqueous solution process. Fourier transform infrared spectroscopy and thermogravimetric analysis both verified the successful attachment of nGO and scanning electron microscopy depicted a homogeneous dispersion of nGO over the scaffold surface. Mechanical tests were performed and demonstrated a significant increase in compressive strength for the nGO grafted scaffolds. Grafting of nGO was also shown to induce mineralization with the formation of calcium phosphate precipitates on the surface of the scaffolds with the size increasing with higher nGO content. The potential of surface-grafted nGO as a nanocarrier of an antibiotic drug was also explored. The secondary interactions between nGO and ciprofloxacin, a broad-spectrum antibiotic used in the treatment of osteomyelitis, were optimized by controlling the solution pH. Ciprofloxacin was found to be adsorbed most strongly in its cationic form at pH 5, in which pi-pi electron donor-acceptor interactions predominate and the adsorbed drug content increased with increasing nGO amount. Further, the release kinetics of the drug were investigated during 8 days. In conclusion, the proposed simple fabrication process led to a scaffold with multifunctionality in the form of improved mechanical strength, ability to induce mineralization, as well as drug loading and delivery capability.

  • 104.
    Erlandsson, Johan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Francon, Hugo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Marais, Andrew
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Granberg, Hjalmar
    RISE Bioecon, Papermaking & Packaging, Box 5604, SE-11486 Stockholm, Sweden..
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Cross-Linked and Shapeable Porous 3D Substrates from Freeze-Linked Cellulose Nanofibrils2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 2, s. 728-737Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chemically cross-linked highly porous nano cellulose aerogels with complex shapes have been prepared using a freeze-linking procedure that avoids common post activation of cross-linking reactions and freeze-drying. The aerogel shapes ranged from simple geometrical three-dimensional bodies to swirls and solenoids. This was achieved by molding or extruding a periodate oxidized cellulose nanofibril (CNF) dispersion prior to chemical cross-linking in a regular freezer or by reshaping an already prepared aerogel by plasticizing the structure in water followed by reshaping and locking the aerogel into its new shape. The new shapes were most likely retained by new cross-links formed between CNFs brought into contact by the deformation during reshaping. This self-healing ability to form new bonds after plasticization and redrying also contributed to the mechanical resilience of the aerogels, allowing them to be cyclically deformed in the dry state, reswollen with water, and redried with good retention of mechanical integrity. Furthermore, by exploiting the shapeability and available inner structure of the aerogels, a solenoid-shaped aerogel with all surfaces coated with a thin film of conducting polypyrrole was able to produce a magnetic field inside the solenoid, demonstrating electromagnetic properties. Furthermore, by biomimicking the porous interior and stiff exterior of the beak of a toucan bird, a functionalized aerogel was created by applying a 300 mu m thick stiff wax coating on its molded external surfaces. This composite material displayed a 10-times higher elastic modulus compared to that of the plain aerogel without drastically increasing the density. These examples show that it is possible to combine advanced shaping with functionalization of both the inner structure and the surface of the aerogels, radically extending the possible use of CNF aerogels.

  • 105.
    Erlandsson, Johan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Pettersson, Torbjörn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Ingverud, Tobias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Granberg, H.
    Larsson, Per A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    On the mechanism behind freezing-induced chemical crosslinking in ice-templated cellulose nanofibril aerogels2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 40, s. 19371-19380Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The underlying mechanism related to freezing-induced crosslinking of aldehyde-containing cellulose nanofibrils (CNFs) has been investigated, and the critical parameters behind this process have been identified. The aldehydes introduced by periodate oxidation allows for formation of hemiacetal bonds between the CNFs provided the fibrils are in sufficiently close contact before the water is removed. This is achieved during the freezing process where the cellulose components are initially separated, and the growth of ice crystals forces the CNFs to come into contact in the thin lamellae between the ice crystals. The crosslinked 3-D structure of the CNFs can subsequently be dried under ambient conditions after solvent exchange and still maintain a remarkably low density of 35 kg m-3, i.e. a porosity greater than 98%. A lower critical amount of aldehydes, 0.6 mmol g-1, was found necessary in order to generate a crosslinked 3-D CNF structure of sufficient strength not to collapse during the ambient drying. The chemical stability of the 3-D structure can be further enhanced by converting the hemiacetals to acetals by treatment with an alcohol under acidic conditions.

  • 106.
    Farahani, Saina Kishani
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Escalante, Alfredo
    Toriz, Guillermo
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Gatenholm, Paul
    Hansson, Per
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Experimental and Theoretical Evaluation of the Solubility/Insolubility Spruce Xylan (Arabino Glucuronoxylan)2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 3, s. 1263-1270Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The molecular solubility of softwood arabinoglucuronoxylan (AGX) has been thoroughly investigated, and it has been shown that the chemical and physical structures of the extracted hemicellulose are not significantly influenced by different purification steps, but a transient molecular solubility of AGX was observed in aqueous media at low concentrations (1 g/L) when the dissolved macromolecules had a hydrodynamic diameter of up to 10 nm. A phase separation was detected when the concentration was increased to 15 g/L leading to an association of the smaller molecules into fractal structures with a considerably larger diameter, even though the dispersions were still transparent to ocular inspection. Dynamic Light Scattering and Cryo-Transmission Electron Microscopy showed dimensions in the range of 1000 nm. The phase separation of the sample was further characterized by estimating the χ-interaction parameter of AGX in water using the Flory-Huggins theory, and the results supported that water is a poor solvent for AGX. This behavior is crucial when films and hydrogels based on these biopolymers are made, since the association will dramatically affect barrier and mechanical properties of films made from these materials.

  • 107.
    Farahani, Saina Kishani
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vilaplana, Francisco
    KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi.
    Ruda, Marcus
    Hansson, Per
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    The influence of solubility on the adsorption of different Xyloglucan fractions at Cellulose Water InterfacesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Xylogucan (XG) fractions with different molar masses were prepared while preserving the natural structure of the XG. The solubility of the fractions was investigated using light- scattering, chromatography and microscopy techniques. The conformational changes of the XG molecules and their association and phase separation were investigated together with concentration and molar mass changes. The knowledge gained was then applied to investigate the interaction of different XG fractions at cellulose model surfaces using a quartz crystal microbalance with dissipation. The results indicate that there is a cluster formation and phase separation of the XG molecules at the cellulose/water interface induced by the increase in XG concentration close to the surface. Concomitantly, the adsorption regimes are altered for the XG fractions depending on the solubility properties, indicating that the insolubility, association and phase separation of XGs in aqueous media affect their interaction with cellulose. The study is of vital importance for improving the functionality of sustainable materials made from xyloglucan/cellulose natural composites.

  • 108.
    Farhat, Wissam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Stamm, Arne
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Robert-Monpate, Maxime
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Centra, Science for Life Laboratory, SciLifeLab. Ecole Super Chim Organ & Minerale, 1 Allee Reseau Jean Marie Buckmaster, F-60200 Compiegne, France.
    Biundo, Antonino
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Syrén, Per-Olof
    KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Biocatalysis for terpene-based polymers2019Ingår i: Zeitschrift für Naturforschung C - A Journal of Biosciences, ISSN 0939-5075, E-ISSN 1865-7125, Vol. 74, nr 3-4, s. 90-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accelerated generation of bio-based materials is vital to replace current synthetic polymers obtained from petroleum with more sustainable options. However, many building blocks available from renewable resources mainly contain unreactive carbon-carbon bonds, which obstructs their efficient polymerization. Herein, we highlight the potential of applying biocatalysis to afford tailored functionalization of the inert carbocyclic core of multicyclic terpenes toward advanced materials. As a showcase, we unlock the inherent monomer reactivity of norcamphor, a bicyclic ketone used as a monoterpene model system in this study, to afford polyesters with unprecedented backbones. The efficiencies of the chemical and enzymatic Baeyer-Villiger transformation in generating key lactone intermediates are compared. The concepts discussed herein are widely applicable for the valorization of terpenes and other cyclic building blocks using chemoenzymatic strategies.

  • 109.
    Feng, Nianjie
    et al.
    Hubei Univ Technol, Wuhan 430068, Hubei, Peoples R China.;Nanjing Forestry Univ, Nanjing 210037, Jiangsu, Peoples R China..
    Guo, Lifang
    Nanjing Forestry Univ, Nanjing 210037, Jiangsu, Peoples R China..
    Ren, Hao
    Nanjing Forestry Univ, Nanjing 210037, Jiangsu, Peoples R China..
    Xie, Yimin
    Hubei Univ Technol, Wuhan 430068, Hubei, Peoples R China..
    Jiang, Zhihua
    Auburn Univ, Alabama Ctr Paper & Bioresource Engn, Auburn, AL 36849 USA..
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Zhai, Huamin
    Nanjing Forestry Univ, Nanjing 210037, Jiangsu, Peoples R China..
    Changes in chemical structures of wheat straw auto-hydrolysis lignin by 3-hydroxyanthranilic acid as a laccase mediator2019Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 122, s. 210-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    3-Hydroxyanthranilic acid (3-HAA), as a potential natural laccase mediator, was shown to mediate the oxidation of non-phenolic lignin subunits. The problem of cost and toxicity of artificial mediators could be solved to some extent by a further study about the detailed changes of lignin chemistry structures in laccase 3-HAA system (LHS). In this work, wheat straw auto-hydrolysis lignin (AL) was prepared. Oxidations of AL by LHS and laccase 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) system were then investigated, respectively. Various structural changes of AL during the oxidation were characterized by different methods including phenolic hydroxyl group determination, nitrobenzene oxidation, ozonation, gel permeation chromatography, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy. The changes in AL chemical structures were found in LHS, including unit removal, bond cleavage and biopolymerization. Compared to laccase ABTS system, a selective removal of guaiacyl-type lignin in LHS was observed, based on the results of nitrobenzene oxidation and 2D NMR analysis. The selective removal of guaiacyl-type lignin was due to improved aromatic ring cleavage and weaken lignin biopolymerization. The selectivity of guaiacyl-type lignin removal in LHS plays an important role, especially for improving bioconversion efficiency of laccase for guaiacyl-rich lignocellulosic biomass.

  • 110.
    Feng, Zhaoxuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    From Polysaccharides to Functional Materials for Trace Pharmaceutical Adsorption2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The transition to bioeconomy will reduce our dependency on fossil fuels as well as contribute to a more sustainable society. Within this framework, exploitation and development of renewable substitutes to petroleum-based products provides feasible roadmap for the material design. Here a perspective is provided to how the natural polysaccharides chitosan (CS) and/or cellulose (CL) could be elaborated and transformed to high-performance materials with the explicit aim of removing trace pharmaceutical contaminants from the wastewater, thus facilitating the sustainable development. In the first part of the thesis, chitosan and cellulose were converted to the carbon spheres (C-sphere) through a microwave-assisted hydrothermal carbonization process, and C-sphere was further broken down to the nanographene oxide (nGO) via a simple oxidation route. On this foundation, a green pathway was developed for fabrication of biobased materials for wastewater purification. First, macroporous chitosan-based composite hydrogels with controllable properties were developed, where chitosan-derived nGO worked as a functional property enhancer. Second, a further development changing from the bulky hydrogels to microgels consisting of CS composite particles in the microscopic size was achieved by a fast one-pot spraying-drying process. The crosslinking reaction occurred in situ during the spray-drying. Last, the C-sphere by-itself was also believed to be a potential adsorbent for wastewater contaminants. In the next step the prepared systems were evaluated for their capacity to adsorb pharmaceutical contaminants. Diclofenac sodium (DCF) was utilized as the model drug, and the three fabricated bio-adsorbents all demonstrated effective DCF adsorption performance, with the adsorption efficiency varying from 65.6 to 100%. Moreover, the DCF adsorption kinetics, isotherms and thermodynamic study were also investigated to reveal the nature of the adsorption process with the different materials. Finally, chitosan-based microspheres were selected for the reusability study, with the adsorption efficiency above 70% retained after six adsorption-desorption cycles, thus further endowing the promising potential of the fabricated bio-adsorbents for commercial applications.

    Publikationen är tillgänglig i fulltext från 2020-04-20 12:12
  • 111.
    Feng, Zhaoxuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gruetzmacher, Hansjoerg
    Chiappone, Annalisa
    Sangermano, Marco
    Photocrosslinked Chitosan Hydrogels Reinforced with Chitosan-Derived no-Graphene Oxide2019Ingår i: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 220, nr 13, artikel-id 1900174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chitosan and chitosan-derived nano-graphene oxide carbon dots are successfully methacrylated and utilized for the fabrication of photocurable hydrogels. The addition of the nano-graphene oxide (nGO) does not significantly delay the polymer network build-up, but significantly reduces the storage modulus of the crosslinked network, with important detrimental effects on the mechanical performance. By replacing nGO with methacrylated M-nGO, the mechanical performance of the crosslinked polymer network is improved with an increase of the storage modulus as a function of increasing the M-nGO content in the photocurable formulation.

  • 112.
    Feng, Zhaoxuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Odelius, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Tunable chitosan hydrogels for adsorption: Property control by biobased modifiers2018Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 196, s. 135-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A sustainable strategy to fabricate chitosan-based composite hydrogels with tunable properties and controllable adsorption capacity of trace pharmaceuticals was demonstrated. Two biobased modifiers were utilized to tune the properties, nano-graphene oxide (nGO) derived from chitosan via microwave-assisted carbonization and oxidation, and genipin as the crosslinking agent. An increase in genipin content facilitated an increase in the degree of crosslinking as shown by improved storage modulus and decreased swelling ratio. Increasing nGO content changed the surface microtopography of the hydrogel which correlated with the surface wettability. nGO also catalyzed the genipin-crosslinking reaction. The hydrogel was further shown to be an effective adsorbent for a common anti-inflammatory drug, diclofenac sodium (DCF), with the removal efficiency ranging from 91 to 100% after 48 h. DCF adsorption efficiency could be tuned through simple alteration of nGO and genipin concentration, which provides promising potential for this environmental-friendly adsorbent in removal of DCF from pharmaceutical waste water.

  • 113.
    Feng, Zhaoxuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Odelius, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Rajarao, Gunaratna Kuttuva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Microwave carbonized cellulose for trace pharmaceutical adsorption2018Ingår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 346, s. 557-566Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A promising sustainable strategy to valorize cellulose to high-value adsorbents for trace pharmaceuticals, like diclofenac sodium (DCF), in the water is demonstrated. Carbon nanospheres (CN) as the DCF adsorbent were derived from cellulose through a one-pot microwave-assisted hydrothermal carbonization method. CN exhibited efficient DCF removal (100% removal of 0.001 mg/mL DCF in 30 s and 59% removal of 0.01 mg/mL DCF in 1 h). The adsorption kinetics and isotherm data were well-fitted with the pseudo-second-order kinetic model and Langmuir model, respectively. The adsorption process was endothermic and spontaneous as confirmed by the thermodynamic parameters. Multiple characterization techniques including SEM/EDS, FTIR, FTIR-imaging and zeta potential were applied to qualitatively investigate the adsorption process. π-π stacking and hydrogen bonding were proposed as the dominant adsorption interactions. CN also demonstrated effective adsorption capacity towards three other commonly-detected contaminants in the wastewater including ketoprofen (KP), benzophenone (BZP), and diphenylamine (DPA), each bearing partial structural similarity with DCF. The affinity of the contaminants towards CN followed the order DPA > BZP > DCF > KP, which could be explained by the different configurations and chemical units. It was speculated that for DCF and KP, the steric hindrance and electrostatic repulsion produced by dissociated carboxyl groups can impede the adsorption process as compared to DPA and BZP. This methodology could offer further insights into the drug adsorption on the cellulose-derived carbon adsorbents and the use of bioderived carbons for treatment of wastewaters contaminated with pharmaceuticals.

  • 114.
    Feng, Zhaoxuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Takahiro, Danjo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo.
    Odelius, Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Tadahisa, Iwata
    Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Recyclable fully biobased chitosan adsorbents spray-dried in one-pot to microscopic size and enhanced adsorption capacity2019Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 20, nr 5, s. 1956-1964Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A facile one-pot spray-drying process was developed for fabrication and in-situ crosslinking of chitosan microspheres to improve the adsorption capacity by microscopic design. A fully biobased nature was achieved by utilizing genipin (GP) as a crosslinking agent and chitosan derived nano-graphene oxide (nGO) as a property tuner. The produced chitosan microspheres were further proven as powerful adsorbents for common wastewater contaminants such as anionic dyes and pharmaceutical contaminants, here modelled by methyl orange (MO) and diclofenac sodium (DCF). By regulating the amount of GP and nGO, as well as by controlling the process parameters including the spraydrying inlet temperature and post-heat treatment, the surface morphology, size, zeta potential and adsorption efficiency of the microspheres could be tuned accordingly. The adsorption efficiency for MO and DCF reached 98.9 and 100 %, respectively. The microspheres retained high DCF adsorption efficiency after six adsorption and desorption cycles and the recyclability was improved by incorporated nGO. The fabricated microspheres, thus, have great potential as reusable and eco-friendly adsorbents.

  • 115.
    Finnveden, Maja
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Brännström, Sara
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Martinelle, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi.
    Novel sustainable synthesis of vinyl ether ester building blocks, directly from carboxylic acids and the corresponding hydroxyl vinyl ether, and their photopolymerization2018Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 44, s. 24716-24723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increased environmental awareness has led to a demand for sustainable, bio-based materials. Consequently, the development of new benign synthesis pathways utilizing a minimum of reaction steps and available bio-based building blocks is needed. In the present study, vinyl ether alcohols and functional carboxylic acids were used to synthesize bifunctional vinyl ether esters using the immobilized enzyme Candida antarctica lipase B as a catalyst. Vinyl ethers are attractive alternatives to (meth)acrylates due to low allergenic hazards, low toxicity, and fast polymerization; however, difficult synthesis limits the monomer availability. The synthesis was performed in one-pot and the described method was successful within a broad temperature range (22-90 degrees C) and in various organic solvents as well as in the bulk. The synthesis of different vinyl ether esters reached high conversions (above 90%) after less than 1 h and products were purified by removing the enzyme by filtration using only small amounts of acetone. This approach is a straightforward route to reach monomers with multiple types of functionalities that can be used as different photo-curable thermoset resins. In this work, this was demonstrated by polymerizing the monomers with cationic and radical UV-polymerization. By changing the functional carboxylic acids, the architecture of the final polymer can be tailored, herein demonstrated by two examples. In the developed versatile method, carboxylic acids can be used directly as acyl donors, constituting a more sustainable alternative to the carboxylic acid derivatives used today.

  • 116.
    Fu, Qiliang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, WWSC, Dept Fibre & Polymer Technol, Stockholm, Sweden..
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH Royal Inst Technol, WWSC, Dept Fibre & Polymer Technol, Stockholm, Sweden..
    Hierarchically structured nanoporous template based on balsa wood2016Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift (Övrigt vetenskapligt)
  • 117.
    Fu, Qiliang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Honeycomb like templates prepared from balsa wood2015Ingår i: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the current study, we have used sodium chlorite and sodium hydroxide as extraction solutions, to remove lignin and hemicelluloses from the Balsa (Ochroma Lagopus) wood tissues, without damaging the wood honeycomb architecture. Surface morphologies are studied using scanning electron microscopy (SEM). In addition, sugars analysis of the chemically extracted wood is reported. 

  • 118.
    Fu, Qiliang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Yan, Min
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Jungstedt, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Yang, Xuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Transparent plywood as a load-bearing and luminescent biocomposite2018Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 164, s. 296-303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent wood (TW) structures in research studies were either thin and highly anisotropic or thick and isotropic but weak. Here, transparent plywood (TPW) laminates are investigated as load-bearing biocomposites with tunable mechanical and optical performances. Structure-property relationships are analyzed. The plies of TPW were laminated with controlled fiber directions and predetermined stacking sequence in order to control the directional dependence of modulus and strength, which would give improved properties in the weakest direction. Also, the angular dependent light scattering intensities were investigated and showed more uniform distribution. Luminescent TPW was prepared by incorporation of quantum dots (QDs) for potential lighting applications. TPW can be designed for large-scale use where multiaxial load-bearing performance is combined with new optical functionalities.

  • 119.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mathisen, T.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Minimizing the time gap between service lifetime and complete resorption of degradable melt-spun multifilament fibers2019Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 163, s. 43-51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have succeeded to modulated the degradation rate of poly(L-lactide) (PLLA) melt-spun multifilament fibers to extend the service lifetime and increase the resorption rate by using random copolymers of L-lactide and trimethylene carbonate (TMC). The presence of TMC units enabled an overall longer service lifetime but faster degradation kinetics than PLLA. By increasing the amount of TMC up to 18 mol%, multifilament fibers characterized by a homogenous degradation profile could be achieved. Such composition allowed, once the mechanical integrity was lost, a much longer retention of mechanical integrity and a faster rate of mass loss than samples containing less TMC. The degradation profile of multifilament fibers consisting of (co)polymers containing 0, 5, 10 and 18 mol% of TMC has been identified during 45 weeks in vitro hydrolysis following the molecular weight decrease, mass loss and changes in microstructure, crystallinity and mechanical properties. The fibers degraded by a two-step, autocatalyzed bulk hydrolysis mechanism. A high rate of molecular weight decrease and negligible mass loss, with a consequent drop of the mechanical properties, was observed in the early stage of degradation for fibers having TMC content up to 10 mol%. The later stage of degradation was, for these samples, characterized by a slight increase in the mass loss and a negligible molecular weight decrease. Fibers prepared with the 18 mol% TMC copolymer showed instead a more homogenous molecular weight decrease ensuring mechanical integrity for longer time and faster mass loss during the later stage of degradation.

  • 120.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mathisen, Torbjorn
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Poly(L-lactide) and Poly(L-lactide-co-trimethylene carbonate) Melt-Spun Fibers: Structure-Processing-Properties Relationship2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 3, s. 1346-1361Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    l-Lactide/trimethylene carbonate copolymers have been produced as multifilament fibers by high-speed melt-spinning. The relationship existing between the composition, processing parameters and physical properties of the fibers has been disclosed by analyzing how the industrial process induced changes at the macromolecular level, i.e., the chain microstructure and crystallinity development. A poly(l-lactide) and three copolymers having trimethylene carbonate contents of 5, 10 and 18 mol % were synthesized with high molecular weight (M n ) up to 377 kDa and narrow dispersity. Their microstructure, crystallinity and thermal properties were dictated by the composition. The spinnability was then assessed for all the as-polymerized materials: four melt-spun multifilament fibers with increasing linear density were collected for each (co)polymer at a fixed take-up speed of 1800 m min -1 varying the mass throughput during the extrusion. A linear correlation resulted between the as-spun fiber properties and the linear density. The as-spun fibers could be further oriented, developing more crystallinity and improving their tensile properties by a second stage of hot-drawing. This ability was dependent on the composition and crystallinity achieved during the melt-spinning and the parameters selected for the hot-drawing, such as temperature, draw ratio and input speed. The crystalline structure evolved to a more stable form, and the degree of crystallinity increased from 0-52% to 25-66%. Values of tensile strength and Young's modulus up to 0.32-0.61 GPa and 4.9-8.4 GPa were respectively achieved.

  • 121. Garcia-Garcia, D.
    et al.
    Lopez-Martinez, J.
    Balart, R.
    Strömberg, Emma
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. HIS-University of Skövde, Skövde.
    Reinforcing capability of cellulose nanocrystals obtained from pine cones in a biodegradable poly(3-hydroxybutyrate)/poly(ε-caprolactone) (PHB/PCL) thermoplastic blend2018Ingår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 104, s. 10-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, different loads (3, 5 and 7 wt%) of pine cone cellulose nanocrystals (CNCs) were added to films of poly(3-hydroxybutyrate)/poly(ε-caprolactone) (PHB/PCL) blends with a composition of 75 wt% PHB and 25 wt% PCL (PHB75/PCL25). The films were obtained after solvent casting followed by melt compounding in an extruder and finally subjected to a thermocompression process. The influence of different CNCs loadings on the mechanical, thermal, optical, wettability and disintegration in controlled compost properties of the PHB75/PCL25 blend was discussed. Field emission scanning electron microscopy (FESEM) revealed the best dispersion of CNCs on the polymeric matrix was at a load of 3 wt%. Over this loading, CNCs aggregates were formed enhancing the films fragilization due to stress concentration phenomena. However, the addition of CNCs improved the optical properties of the PHB75/PCL25 films by increasing their transparency and accelerated the film disintegration in controlled soil conditions. In general, the blend with 3 wt% CNCs offers the best balanced properties in terms of mechanical, thermal, optical and wettability.

  • 122.
    Garcia-Garcia, Daniel
    et al.
    UPV, ITM, Plaza Ferrandiz y Carbonell 1, Alicante 03801, Spain..
    Balart, Rafael
    UPV, ITM, Plaza Ferrandiz y Carbonell 1, Alicante 03801, Spain..
    Lopez-Martinez, Juan
    UPV, ITM, Plaza Ferrandiz y Carbonell 1, Alicante 03801, Spain..
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Dept Fibre & Polymer Technol, Sch Engn Sci Chem Biotechnol & Hlth, S-10044 Stockholm, Sweden..
    Moriana, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Optimizing the yield and physico-chemical properties of pine cone cellulose nanocrystals by different hydrolysis time2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 5, s. 2925-2938Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellulose nanocrystals (CNCs) were isolated for the first time from pine cones (PC) by alkali and bleaching treatments and subsequent sulfuric acid hydrolysis (64%) at 45 degrees C. The influence of the hydrolytic reaction time (30, 45, and 90 min) on the yield, chemical composition and structure, and thermal stability of CNCs was evaluated. The removal of non-cellulosic constituents during the alkaline and bleaching treatment resulted in high pure cellulosic fibres. The isolation of CNCs from these cellulosic fibres at different reaction times was verified by the nano-dimensions of the individual crystals (< 3 and < 335 nm of average diameter and length, respectively). The highest yield (15%) and the optimum CNCs properties in terms of aspect ratio, thermal stability and crystallinity were obtained for an extraction time of 45 min. PC appeared to be a new promising source of cellulose fibres and CNCs with potential to be applied as reinforcement in composites and for food-packaging.

  • 123.
    Gazzotti, Stefano
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Adolfsson, Karin H.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ortenzi, Marco Aldo
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Farina, Hermes
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Lesma, Giordano
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Silvani, Alessandra
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    One-Pot Synthesis of Sustainable High-Performance Thermoset by Exploiting Eugenol Functionalized 1,3-Dioxolan-4-one2018Ingår i: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, nr 11, s. 15201-15211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1,3-Dioxolan-4-one (DOX) chemistry was explored for production of "one-pot" biobased polyester thermosets. DOX monomer was first functionalized by naturally occurring eugenol to introduce a structural element, which could induce cross-linking reaction through cationic polymerization of the double bond. The feasibility of polymerizing DOX monomers bearing bulky side groups was proven by model phenol-substituted DOX monomer (PhDOX). Once the reaction was shown to be effective, the same protocol was applied to eugenol-substituted monomer (EuDOX). A brief screening of the optimal catalyst concentration was performed, to obtain a highly cross-linked product. The synthesized thermoset showed good thermal resistance and high mechanical strength probably due to the rich aromatic content. The obtained thermoset was further subjected to microwave-assisted hydrothermal degradation test, which demonstrated complete recyclability to water or methanol soluble products. NMR and matrix-assisted laser desorption/ionization-mass spectroscopy analyses of the obtained degradation products unveiled the structure of the thermoset, strongly indicating that the polymerization of eugenol-functionalized DOX monomer resulted in polylactide-like chains connected with aromatic aliphatic segments resulting from the reaction of the eugenol double bonds. The presence of free hydroxyl and carboxyl groups sheds light on the mechanism behind the observed shape-memory and self-healing properties.

  • 124.
    Gazzotti, Stefano
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;K;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Rampazzo, Riccardo
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bussini, Daniele
    INNOVHUB SSI Paper Dept, Via Giuseppe Colombo 83, I-20133 Milan, Italy..
    Ortenzi, Marco Aldo
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Farina, Hermes
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Lesma, Giordano
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Silvani, Alessandra
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimer LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Cellulose nanofibrils as reinforcing agents for PLA-based nanocomposites: An in situ approach2019Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 171, s. 94-102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One-pot in situ polymerization approach was explored for the preparation of polylactide (PLA)-cellulose nano-fibril (CNF) bio-nanocomposites. CNF were first prepared through enzymatic and mechanical treatment of bleached hardwood kraft pulp. The bio-nanocomposites- were then fabricated through ring opening polymerization (ROP) of L-lactide, in the presence of various amounts of fibrils. Molecular weight, thermal properties, surface morphology, mechanical and wettability properties of the PLA-CNF nanocomposites were evaluated. DSC analysis demonstrated the effect of CNF on crystallization and crystalline morphology of PLA. Improved modulus for the nanocomposites with respect to standard PLA was demonstrated, however, the differences in tensile stress were small probably due to the counteracting effects of reinforcement from CNF and the decreasing molecular weight as a function of CNF concentration. The absence of pulled-out fibers was assessed, highlighting the strong interface and covalent attachment of PLA chains on CNF surface. Finally, the covalent bonding of PLA chains on CNF surface was demonstrated by isolating the non-soluble part, consisting of PLA-grafted CNF, and characterization of this residue.

  • 125.
    Gedde, Ulf W
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lifetime prediction: Different strategies by example2007Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 233Artikel i tidskrift (Övrigt vetenskapligt)
  • 126. Geng, S.
    et al.
    Yao, Kun
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Harila, M.
    Zhou, Qi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Oksman, K.
    Grafting polyethylene glycol on nanocellulose toward biodegradable polymer nanocomposites2017Ingår i: ICCM International Conferences on Composite Materials, International Committee on Composite Materials , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The reinforcing effect of a small amount of nanocellulose materials on biodegradable and polymer-based nanocomposites remains challenging because of the poor dispersion of the nanomaterials and inefficient interaction between the nanocellulose and the polymer matrix. To improve this, we grafted polyethylene glycol (PEG) on nanocellulose and produced composites of 0.1 wt% nanocellulose materials and polylactic acid (PLA) matrix. Here, two types of PEG grafted nanocellulose including TEMPO-oxidized cellulose nanocrystals (TOCNCs) and cellulose nanofibers (TOCNFs), with different lengths and diameters were used as reinforcements, respectively. We investigated the effects of grafting PEG on microstructure, mechanical properties and thermal behaviors of the PLA/nanocellulose composites. It is found that the PEG grafted nanocellulose dispersed better compared to the unmodified nanocellulose in the PLA matrix, and provides higher reinforcing effect that improves the elastic modulus of the nanocomposites compared to the composites with unmodified nanocellulose and ungrafted PEG. However, the glass transition temperature of the nanocomposites was not improved by grafting PEG significantly. We also found that the nanocomposites reinforced by TOCNF exhibited enhanced mechanical and thermal properties compared to those with TOCNCs, which is caused by the higher aspect ratio of the TOCNFs. 

  • 127.
    Geng, Shiyu
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Luleå Univ Technol, Div Mat Sci, Dept Engn Sci & Math, SE-97187 Luleå, Sweden.
    Yao, Kun
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Zhou, Qi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Oksman, Kristiina
    Luleå Univ Technol, Div Mat Sci, Dept Engn Sci & Math, SE-97187 Luleå, Sweden.;Univ Oulu, Fibre & Particle Engn, FI-90014 Oulu, Finland..
    High-Strength, High-Toughness Aligned Polymer-Based Nanocomposite Reinforced with Ultralow Weight Fraction of Functionalized Nanocellulose2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 10, s. 4075-4083Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multifunctional lightweight, flexible, yet strong polymer-based nanocomposites are highly desired for specific applications. However, the control of orientation and dispersion of reinforcing nanoparticles and the optimization of the interfacial interaction still pose substantial challenges in nanocellulose-reinforced polymer composites. In this study, poly(ethylene glycol) (PEG)-grafted cellulose nanofibers have demonstrated much better dispersion in a poly(lactic acid) (PLA) matrix as compared to unmodified nanocellulose. Through a uniaxial drawing method, aligned PLA/nanocellulose nanocomposites with high strength, high toughness, and unique optical behavior can be obtained. With the incorporation of 0.1 wt % of the PEG-grafted cellulose nanofibers in PLA, the ultimate strength of the aligned nanocomposite reaches 343 MPa, which is significantly higher than that of other aligned PLA-based nanocomposites reported previously. Moreover, its ultimate strength and toughness are enhanced by 39% and 70%, respectively, as compared to the aligned nanocomposite reinforced with unmodified cellulose nanofibers. In addition, the aligned nanocomposite film is highly transparent and possesses an anisotropic light scattering effect, revealing its significant potential for optical applications.

  • 128. Ghaani, M.
    et al.
    Rovera, C.
    Pucillo, F.
    Ghaani, M. R.
    Olsson, Richard T.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Scampicchio, M.
    Farris, S.
    Determination of 2,4-diaminotoluene by a bionanocomposite modified glassy carbon electrode2018Ingår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 277, s. 477-483Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work describes the development of a modified glassy carbon electrode (GCE) for the selective determination of 2,4-diaminotoluene (TDA), a primary aromatic amines (PAAs) that can be formed in food packaging materials including aromatic polyurethane (PU) adhesives. The electrode's surface was modified with multi-walled carbon nanotubes (MWCNTs), MWCNTs in chitosan (CS), and gold nanoparticles (AuNPs). The highest current response was achieved with AuNPs/MWCNTs-CS/GC electrodes, which exhibited an oxidation peak of 9.87 μA by cyclic voltammetry (CV), compared with 1.39 μA of the bare GCE. A detection limit of 35 nM was estimated by amperometry experiments. The oxidation of TDA was strongly dependent on the pH of the medium, having maximum sensitivity at pH ∼ 7. From a mechanistic point of view, the diffusion coefficient of TDA (D = 6.47 × 10−4 cm2 s−1) and the number of electrons (n ≈ 2) involved in the catalytic oxidation of TDA at the surface of the AuNPs/MWCNTs-CS/GCE were determined. The practical utility of this nanocomposite modified electrode was demonstrated by migration studies from conventional food packaging materials. 

  • 129.
    Ghanadpour, Maryam
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Phosphorylated Cellulose Nanofibrils: A Nano-Tool for Preparing Cellulose-Based Flame-Retardant Materials2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The growing awareness of the need for a circular society and a circular chemistry has spurred the interest in using wood-based cellulose as a raw material for the preparation of new macroscopic devices and construction materials. The interest has been particularly focused on cellulose nanofibrils (CNF), which has led to the development of new material concepts through a nanoscale bottom-up engineering using renewable CNF. In order to be industrially applicable, the CNF must however possess a set of properties among which good flame-retardation is crucial. This thesis presents a) a way to chemically modify delignified wood fibers by phosphorylation to produce phosphorylated CNF, b) the fabrication and characterization of flame-retardant thin films, coatings and nanocomposite foams from the phosphorylated fibrils and c) the flame-retardant mechanisms of the phosphorylated CNF-based substances.

    Chemically delignified fibers have been phosphorylated by (NH4)2HPO4 in the presence of urea, and the resulting material has been used to prepare phosphorylated CNF (P-CNF). The flame-retardant properties of the phosphorylated fibrils were significantly improved by the phosphorus functionalization of the cellulose chain, converting the fibrils to an inherently flame-retardant material. The P-CNF was applied to make thin films/coatings using the Layer-by-Layer (LbL) technique. All-cellulose free-standing films were prepared through LbL self-assembly of the P-CNF and fibrils prepared from aminated cellulose-rich fibers (cationic CNF). The LbL-assembled film showed a high thermal stability, excellent flame resistance and superior mechanical performance. P-CNF/chitosan (CH) assemblies were also prepared as a fire protection for polyurethane (PU) foams. The five bilayer CH/P-CNF coating yielded a nano-exoskeleton on the surface of PU foam, shown to be capable of increasing the modulus of the foam by a factor of three and entirely preventing its melt dripping during the flammability testing.

    P-CNF/montmorillonite (MMT), sepiolite (Sep) clay or sodium hexametaphosphate (SHMP) films were also fabricated by vacuum filtration/solvent casting of the composite suspensions, and the structural and compositional features of these different films were used to study the mechanisms behind their flame-retardant properties. Only the P-CNF/MMT films were able to completely prevent ignition during cone calorimetry, when used as coatings for highly flammable polyethylene (PE) films and this was mainly ascribed to the excellent barrier properties of these films. The results also showed that the excellent strength and stiffness of the P-CNF/MMT samples, compared to those of the P-CNF/Sep and P-CNF/SHMP films, were essential for maintaining the barrier effect during combustion. Finally, nanostructured foams were prepared by freeze-casting of the P-CNF/Sep suspensions. The foams showed extensive flame-resistance, maintaining a temperature drop of more than 600 °C across the thickness during the flame penetration test. This performance was related mainly to the charring capability of the phosphorylated fibrils combined with the significant thermal insulation of Sep clay.

  • 130.
    Ghanadpour, Maryam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Carosio, F.
    Ruda, M. C.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Tuning the Nanoscale Properties of Phosphorylated Cellulose Nanofibril-Based Thin Films to Achieve Highly Fire-Protecting Coatings for Flammable Solid Materials2018Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 38, s. 32543-32555Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ultrathin nanocomposite films were prepared by combining cellulose nanofibrils (CNFs) prepared from phosphorylated pulp fibers (P-CNF) with montmorillonite (MMT), sepiolite (Sep) clay, or sodium hexametaphosphate (SHMP). The flame-retardant and heat-protective capability of the prepared films as casings for a polyethylene (PE) film was investigated. Heating the coated PE in air revealed that the polymer film was thoroughly preserved up to at least 300 °C. The P-CNF/MMT coatings were also able to completely prevent the ignition of the PE film during cone calorimetry, but neither the P-CNF/Sep nor the P-CNF/SHMP coating could entirely prevent PE ignition. This was explained by the results from combined thermogravimetry Fourier transform infrared spectroscopy, which showed that the P-CNF/MMT film was able to delay the release of PE decomposition volatiles and shift its thermal degradation to a higher temperature. The superior flame-retardant performance of the P-CNF/MMT films is mainly attributed to the unique compositional and structural features of the film, where P-CNF is responsible for increasing the char formation, whereas the MMT platelets create excellent barrier and thermal shielding properties by forming inorganic lamellae within the P-CNF matrix. These films showed a tensile strength of 304 MPa and a Young's modulus of 15 GPa with 10 wt % clay so that this composite film was mechanically stronger than the previously prepared CNF/clay nanopapers containing the same amount of clay. 

  • 131.
    Ghanadpour, Maryam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Carosio, F
    Ruda, M.C.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Flame-retardant nanocomposite thin films based on phosphorylated cellulose nanofibrils: A study of flame-retardant mechanisms2018Ingår i: Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 132.
    Ghanadpour, Maryam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Wicklein, Bernd
    Carosio, Federico
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    All-natural and highly flame-resistant freeze-cast foams based on phosphorylated cellulose nanofibrils2018Ingår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 10, nr 8, s. 4085-4095Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pure cellulosic foams suffer from low thermal stability and high flammability, limiting their fields of application. Here, light-weight and flame-resistant nanostructured foams are produced by combining cellulose nanofibrils prepared from phosphorylated pulp fibers (P-CNF) with microfibrous sepiolite clay using the freeze-casting technique. The resultant nanocomposite foams show excellent flame-retardant properties such as self-extinguishing behavior and extremely low heat release rates in addition to high flame penetration resistance attributed mainly to the intrinsic charring ability of the phosphorylated fibrils and the capability of sepiolite to form heat-protective intumescent-like barrier on the surface of the material. Investigation of the chemical structure of the charred residue by FTIR and solid state NMR spectroscopy reveals the extensive graphitization of the carbohydrate as a result of dephosphorylation of the modified cellulose and further dehydration due to acidic catalytic effects. Originating from the nanoscale dimensions of sepiolite particles, their high specific surface area and stiffness as well as its close interaction with the phosphorylated fibrils, the incorporation of clay nanorods also significantly improves the mechanical strength and stiffness of the nanocomposite foams. The novel foams prepared in this study are expected to have great potential for application in sustainable building construction.

  • 133.
    Ghorbani, Morteza
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning.
    Svagan, Anna Justina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Grishenkov, Dmitry
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Medicinsk avbildning. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Karolinska Institutet (KI), CLINTEC – Division of Medical Imaging and Technology.
    Acoustic Response of a Novel Class of Pickering Stabilized Perfluorodroplets2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Introduction

    Acoustic Droplet Vaporization (ADV) is a phase change phenomenon in which the liquid state, in the form of droplets, is converted to gas as a result of bursts in the excited ultrasound field. Having a wide range of medical applications, ADV has drawn considerable attention in imaging [1], diagnosis and critical medical treatment [2]. Therefore, benefitting from its broad potentials, with the consideration of its capability in localized noninvasive energy exposure, it is possible to utilize its effect in different medical applications from targeted drug delivery [3] to embolotherapy [4].

    Apart from the droplet characterization and ADV effectiveness on the applied region, the physics of ADV and particularly the ultrasound analysis is an essential parameter in the initiation of the vaporization. This part, which is related to acoustic wave physics, implies that ADV is mostly dependent on ultrasound pressure, frequency and temperature. In this sense, Miles et al. [5] tried to find incident negative pressure - called as ADV threshold- which is necessary for the induction of nucleation. It was successfully shown that the negative pressure required for the nucleation prior to collapse can be determined via perturbation analysis of a compressible inviscid flow around a droplet for various frequencies and diameters. In addition, the fluid medium which constitutes the droplet emulsion and the surrounding fluid constructs a significant field within ADV. In this regard, there are many studies which illustrated that the diameter of the droplets subjected to the acoustic waves undergoes a significant expansion of 5 to 6 times of their regular sizes [6-8].

    In this study, a new type of pickering stabilized perfluorodroplets (PFC) was examined under the effect of the different acoustic parameters to evaluate its potential in the acoustic droplet vaporization process. To assess the pressure effects on the stabilized droplets, the acoustic power within the ultrasound tests was varied and the phase trasnition was characterized according to the experimental conditions. Opticell® was utilized as the transparent device to visualize the droplets, which were exposed to the acoustic waves with the aid of the microscope and multi-well microplate.

    Methods

    Materials and emulsion preparation

    Perfluoropentane (PFC5) was purchased from Apollo Scientific (City, U.K.). Bleached sulfite pulp (from Nordic Paper Seffle AB, Sweden) was used in the production of the cationic cellulose nanofibers (CNFs). The CNF suspension (1.32 wt%) were prepared as described previously [9]. The CNFs had a dimension of 3.9 ± 0.8 nm in width and a length in the micrometer range. The amount of cationic groups was 0.13 mmol per g fiber, obtained from conductometric titration [9]. A suspension of CNF (0.28 wt%) was prepared by diluting the stock CNF with MilliQ-water (pH of diluted CNF suspension was 9.5). The suspension was treated with ultra-sonication at amplitude of 90% for 180 s (Sonics, Vibracell W750). The suspension was brought to room temperature. An amount of 36 g of the 0.28 wt% CNF suspension was mixed with 1 g of PFC5. The mixture was sonicated for 60s at an amplitude of 80% (under ice-cooling) to obtain the CNF-stabilized PFC5 droplets.

    The protocol for the acoustic tests

    100 μL of CNF-stabilized PFC5 droplets were added to 1900 μL of deionized water in order to prepare the solution which were exposed to the ultrasound waves. The droplet sample, diluted 1:19 in distilled water was introduced to the Opticell® and the acoustic waves at a fixed frequency and different powers were applied to the trageted area inside the Opticell® which is located inside a water bath. The ultrasound triggered sample then was placed under a 20X magnification objective of upright transmitted light microscope (ECLIPSE Ci-S, Nikon, Tokyo, Japan). 

    The acoustic tests were performed using high-power tone burst pulser-receiver (SNAP Mark IV,  Ritec, Inc., Warwick, RI, USA) equipped with a transducer (V382-SU Olympus NDT, Waltham, MA ) operating at the frequency of 3.5 MHz. The emulsion of CNF-stabilized PFC5 droplets were exposed to the power range which has the acsending trend from -30 to 0 dB at the given frequency. To investigate the droplet size variations at each power between, the droplets were collected inside the Opticell® and the droplet diameter was measured with the aid of the ImageJ software (version 1.50b, National institutes of health, USA) to determine the concentration and size distribution. The Gaussian distribution is ploted with mean value and standad deviation recover from the experimental data. An in-house image edge detection MATLAB™ script (MathWorks Inc., Natick, MA) were applied to analyze the images obtained from the microscope and provides the size and volume distributions.

    Results

    The size of PFP droplets is an important parameter to controll in the therapeutic applications. Here, a new type of Pickering stabilized perfluorodroplets were prepared where the PFP/water interface was stabilized with cellulose nanofibers (CNF) and the size of the droplets could easily be controlled by varying the amount of CNF added.  The resulting droplets were investigated using a single crystal transducer. Apart from the medical applications, controlling the droplet size is important from droplet dynamics point of view, becausethe interfacial energy is crucial in the assumption of the critical nucleus radius. Therefore, it is possible to estimate the negative peak pressure required for the phase transition once the droplet is controlled and interfacial energy deposited inside and on the surface of the droplet are balanced.

    According to the results in Figure 1, there is an appreciable rise of the size of the droplets after ultrasound waves exposure, particularly at -8 dB power. The experiments were performed for 30 seconds at different powers ranging from -30 to 0 dB, while the frequency was kept constant at 3.5 MHz, burst width in cycles was selected as 12 and repetition rate was set to 100. Images included in Figure 1 demonstrate major transitions in the intervals at -16, -8 and 0 dB. As shown in this figure, the droplet size increased with the power rise and more bubbles with bigger sizes appears at higher powers. This outcome implies the significant role of the applied frequency and power on the phase shift and subsequent mechanisms as a result of the acoustic wave exposure on the new nontoxic and incompatible droplet type.

    Figure 2 shows the average number of droplets and volume distribution at the corresponding powers to the Figure 1. It is shown that while the average diameter of the droplets is around 3.5 µm, the generated bubbles, as a result of the ADV, reaches up to 15 µm at the highest possible power. For each set of experiment (corresponding to a given power) 32 images were taken, thus, to reduce the errors and obtain the standard deviation (approximately 0.8 for all the cases), the presented diagrams for the droplet distributions exhibits the mean value for all of the acquired images. Therefore, it is shown that the droplet emulsion exhibited in NO US in Figure 2, which shows the regular view and distribution range of the CNF-stabilized PFC5 droplets at the room temperature, experiences ADV process with the diameter rise of about 5 times at the highest power when the frequency is fixed at 3.5 MHz.

    Conclusions

    The results show that there is appreciable rise on the size of the droplets after ultrasound waves exposure at a fixed frequency. Acoustic droplet vaporization (ADV) was illustrated at different powers for CNF-stabilized PFC5 droplets as a new class of pickering stabilized perfluorodroplets with the increase in the size of the droplets and following phase trasition to bubbles. Diameter increase of 5 times were obtained after the ultrasound exposure indicating the efficiency of the suggested droplets for the ADV process and therapeutic applications.   

    References

    [1] Arena CB, Novell A, Sheeran PS, Puett C, Moyer LC, Dayton PA, Dual-Frequency Acoustic Droplet Vaporization Detection for Medical Imaging 2015, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 62: 9.

    [2] Kripfgans OD, Fowlkes JB, Miller DL, Eldevik OP, Carson PL, Acoustic droplet vaporization for therapeutic and diagnostic applications 2000, Ultrasound Med. Biol, 26:1177–1189.

    [3] Kang ST, Yeh CK, Intracellular Acoustic Droplet Vaporization in a Single Peritoneal Macrophage for Drug Delivery Applications 2011, Langmuir, 27:13183–13188.

    [4] Zhu M, Jiang L, Fabiilli ML, Zhang A, Fowlkes JB, Xu LX, Treatment of murine tumors using acoustic droplet vaporization-enhanced high intensity focused 2013, Ultrasound Phys. Med. Biol, 58:6179–6191.

    [5] Miles CJ, Doering CR, Kripfgans OD, Nucleation pressure threshold in acoustic droplet vaporization 2016, Journal of Applied Physics, 120:034903.

    [6] Sheeran PS, Wong VP, Luois S, McFarland RJ, Ross WD, Feingold S, Matsunaga TO, Dayton PA, Decafluorobutane as a phase-change contrast agent for low-energy extravascular ultrasonic imaging 2011, Ultrasound Med. Biol, 37:1518–1530.

    [7] Kripfgans OD, Fowlkes JB, Miller DL, Eldevik OP, Carson PL, Acoustic droplet vaporization for therapeutic and diagnostic applications 2000, Ultrasound Med. Biol, 26:1177–1189.

    [8] Kang S, Huang Y, Yeh C, Characterization of acoustic droplet vaporization for control of bubble generation under flow conditions 2014, Ultrasound Med. Biol, 40:551–561.

    [9] Svagan AJ, Benjamins JW, Al-Ansari Z, Shalom DB, Müllertz A, Wågberg L, Löbmann K, Solid cellulose nanofiber based foams–towards facile design of sustained drug delivery systems 2016, J. Control Release, 244:74–82 (Part A).

     

  • 134.
    Gicquel, Erwan
    et al.
    Univ Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France..
    Martin, Caine
    Univ Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France..
    Gauthier, Quentin
    Univ Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France..
    Engström, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Abbattista, Clara
    Univ Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France..
    Carlmark, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cranston, Emily D.
    Univ British Columbia, Dept Chem & Biol Engn, 2360 East Mall, Vancouver, BC V6T 1Z3, Canada.;Univ British Columbia, Dept Wood Sci, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada..
    Jean, Bruno
    Univ Grenoble Alpes, CNRS, CERMAV, F-38000 Grenoble, France..
    Bras, Julien
    Univ Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France.;Inst Univ France, F-75000 Paris, France..
    Tailoring Rheological Properties of Thermoresponsive Hydrogels through Block Copolymer Adsorption to Cellulose Nanocrystals2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 7, s. 2545-2556Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the adsorption of a block copolymer composed of a poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) cationic polyelectrolyte and a poly(di(ethylene glycol) methyl ethermethacrylate) (PDEGMA) on oxidized cellulose nanocrystals (TO-CNCs) to produce hydrogels. PDMEAMA-b-PDEGMA was synthesized by atom-transfer radical polymerization. The extent and dynamics of the adsorption of PDMAEMA-b-PDEGMA on TO-CNCs were determined by electromechanical microbalance and optical techniques. Electrostatic adsorption was identified on TO-CNCs with the quaternized block copolymer. Small-angle neutron scattering experiments were performed to investigate the polymer behavior on the TO-CNC surfaces. Depending on the temperature, block copolymer induces the aggregation of nanocrystals after adsorption by connecting CNCs bundles with block copolymer chains. A reversible liquid-to-gel transition, triggered by temperature, was clearly detected by rheological measurements for the copolymer-CNC mixtures. At the optimal copolymer to CNC ratio the viscosity increased by 4 orders of magnitude at low shear rates. These stimuli-responsive CNC-based materials could be used as injectable biomedical systems.

  • 135.
    Gioia, Claudio
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lo Re, Giada
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Tunable thermosetting epoxies based on fractionated and well-characterized lignins2018Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126Artikel i tidskrift (Refereegranskat)
  • 136.
    Giummarella, Nicola
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Fundamental Aspects of Lignin Carbohydrate Complexes (LCC): Mechanisms, Recalcitrance and Material concepts2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Existensen av kovalenta bindningar mellan lignin och kolhydrater, som bildar en matris som kallas ligninkolhydratkomplex (LCC), förblir ett av de mest kontroversiella ämnena inom träkemi. En viktig fråga är om de bildas under isolering eller faktiskt finns närvarande i trä före isolering (där isolering innefattar kemiska och mekaniska förbehandlingar av den kompakta trästrukturen). Djupare insikter om deras ursprung och reaktivitet är avgörande för att utröna deras roll i träbildning och deras bidrag till extraktionssvårighet. Lignins bidrag till extraktionssvårighet är av särskilt intresse, då den länge hämmat den framgångsrika utvecklingen av effektiv och ren fraktionering av träpolymerer.För att ta itu med ovan nämnda problem har vi utvecklat ett nytt, milt, universellt och kvantitativt fraktioneringsprotokoll av LCC som i kombination med robusta spektroskopiska analysverktyg (vilka innefattar ett flertal NMR-tekniker samt GC MS och SEC) ger djupare insikt om LCCs molekylära struktur. Detta protokoll applicerades på både barr- och lövved och ledde till intressanta upptäckter beträffande de molekylära regler-mekanismerna för bildandet av lignin-kolhydrat-bindningar (LC). Dessa upptäckter berörde även vikten av hemicellulosors acetylering. Vidare presenterades hur LC-bindningar bidrar till extractionssvårighet under subkritisk vattenutvinning.Biomimetisk in vitro-ligninpolymerisation användes för att vidare undersöka huruvida LC-bindningar finns närvarande innan isolering av trä eller bildas under denna. I denna avhandling har för första gången direkta bevis till stöd för att de bildas nativt i träceller presenterats. Detta korroborerar tidigare mekanismer som föreslagits i litteraturen. Vidare erhölls djupare insikter på molekylär nivå för att föreslår en sekvens för hur LC-bindningar bildas in vitro.Slutligen, av särskilt intresse för materialvetenskap, inspirerade den framtagna LC-bindningsmedelsmekanismen en grön, biomimetisk enstegssyntes av funktionaliserat lignin utgående från monomera komponenter. Utmärkt funktionaliseringsselektivitet uppvisades och en produktion av ligninbaserade återvinningsbara material baserade på denna funktionaliseringsfilosofi diskuteras.

  • 137.
    Giummarella, Nicola
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Nativity of Lignin Carbohydrate Bonds substantiated by novel biomimetic synthesisManuskript (preprint) (Övrigt vetenskapligt)
  • 138.
    Giummarella, Nicola
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Gioia, Claudio
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. Department of Civil, Chemical, Environmental and Materials Engineering. Universita´ di Bologna.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    A One-Pot Biomimetic Synthesis of Selectively Functionalized Lignins from Monomers: A Green Functionalization Platform2018Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin is the most abundant renewable source of phenolic compound with great application potential in renewable materials, biofuels and platform chemicals. Current technology for producing cellulose-rich fibers co-produces heterogeneous lignin, which includes an untapped source of monomeric phenolics. One such monomer also happen to be the main monomer in soft wood lignin biosynthesis, namely coniferyl alcohol. Herein, we investigate the potential of coniferyl alcohol as a platform monomer for the biomimetic production of tailored functionalized oligolignols with desirable properties for material synthesis. Accordingly, a bifunctional molecule with at least one carboxyl-ended functionality is included with coniferyl alcohol in biomimetic lignin synthesis to, in one-pot, produce a functionalized lignin. The functionalization mechanism is a nucleophilic addition reaction to quinone methide intermediate of lignin polymerization. The solvent systems applied were pure water or 50% aqueous acetone. Several bi-functional molecules differing in the second functionality were successfully inserted in the lignin demonstrating the platform component of this work. Detailed characterizations were performed by a combination of NMR techniques which include 1H NMR, COSY-90, 31P NMR, 13C NMR, 13C APT, HSQC, HMBC and HSQC TOCSY. Excellent selectivity towards benzylic carbon and high functionalization degree were noted. The structure of lignin was tailored through solvent system choice, with the 50% aqeuous acetone producing a skeletal structure favorable for high functionalization degrees. Finally, material concepts are demonstrated using classical Thiol-ene- and Diels Alder- chemistries to show potential for thermoset- and thermoplastic- concepts, respectively. The functionalization concept presents unprecedentent opportunities for green production of lignin-based recyclable biomaterials.

  • 139.
    Giummarella, Nicola
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Salmén, Lennart
    Rise Bioecon, Drottning Kristinas Väg 61,Box 5604, SE-11486 Stockholm, Sweden.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    On the effect of hemicellulose removal on cellulose-lignin interactions2017Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 32, nr 4, s. 542-549Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In a recent study, it was suggested that there could be direct associations between cellulose and lignin in mild alkaline cooked pulps. The observation was based on studies showing that the molecular straining of lignin was similar to that of cellulose. This finding has serious ramifications for technical production of pulps as it could expand on what is known about recalcitrant lignin removal during pulping. Herein, we investigate the possible interaction between cellulose and lignin discussing possible mechanisms involved at the nano-and molecular-scales, and present support for that the removal of hemicellulose by hot water extraction or mild kraft pulping causes strong interactions between lignin and cellulose.

  • 140.
    Giummarella, Nicola
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Pu, Yunqiao
    Ragauskas, Arthur J
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    A Critical Review on the Analysis of Lignin Carbohydrate Bonds2018Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Replacing fossil-based resources with renewable alternatives is generally acknowledged as a critical component to address several of today's environmental concerns. In this context, lignocellulosic biomass is an attractive, sustainable resource. However, the constitutional biopolymers of interest are locked in the structural complexity of the plant cell walls, which defines their properties and contributes to fractionation recalcitrance. One of the key suspects restricting fractionation of the biopolymers in high yield is the presence of lignin-carbohydrate bonds forming a matrix referred to as Lignin-Carbohydrate Complexes (LCC). Nevertheless, covalent bonds between lignin and carbohydrates, remain one of the most controversial topics in lignocellulose chemistry. This challenge can be attributed to the slow progress made in their research, which also forms the basis for this review. Herein, we will critically discuss the literature with a particular focus on the latest characterization and analytical techniques. Discussions on existing techniques and, importantly the drawbacks with them should be compelling to researchers in the area, especially at this time when crucial issues surrounding the realization of biorefineries need to be addressed.

  • 141.
    Giummarella, Nicola
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Royal Inst Technol, Wallenberg Wood Sci Ctr, Stockholm, Sweden..
    Zhang, Liming
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Fibre & Polymer Technol, Stockholm, Sweden..
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Royal Inst Technol, Wallenberg Wood Sci Ctr, Stockholm, Sweden.;KTH, Fibre & Polymer Technol, Stockholm, Sweden..
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Royal Inst Technol, Wallenberg Wood Sci Ctr, Stockholm, Sweden..
    Global protocol for the mild quantitative fractionation of lignin carbohydrate complexes (LCC)2016Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Artikel i tidskrift (Övrigt vetenskapligt)
  • 142.
    Gjerde, Cecilie
    et al.
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Mustafa, Kamal
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Hellem, Solve
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Rojewski, Markus
    Ulm Univ, Inst Transfus Med, Ulm, Germany.;Univ Hosp Ulm, Inst Clin Transfus Med & Immunogenet Ulm, Red Cross Blood Serv Baden Wurttemberg Hessen, Ulm, Germany.;Univ Hosp Ulm, Inst Transfus Med, Ulm, Germany..
    Gjengedal, Harald
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Yassin, Mohammed Ahmed
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Feng, Xin
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Skaale, Siren
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Berge, Trond
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Rosen, Annika
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Shi, Xie-Qi
    Univ Bergen, Inst Clin Dent, Bergen, Norway..
    Ahmed, Aymen B.
    Haukeland Hosp, Hematol Sect, Dept Internal Med, Bergen, Norway.;Ctr Canc Biomakers CCBIO, Bergen, Norway.;Univ Bergen, Dept Clin Sci, Precis Oncol Res Grp, Bergen, Norway..
    Gjertsen, Bjorn Tore
    Haukeland Hosp, Hematol Sect, Dept Internal Med, Bergen, Norway.;Ctr Canc Biomakers CCBIO, Bergen, Norway.;Univ Bergen, Dept Clin Sci, Precis Oncol Res Grp, Bergen, Norway..
    Schrezenmeier, Hubert
    Ulm Univ, Inst Transfus Med, Ulm, Germany.;Univ Hosp Ulm, Inst Clin Transfus Med & Immunogenet Ulm, Red Cross Blood Serv Baden Wurttemberg Hessen, Ulm, Germany.;Univ Hosp Ulm, Inst Transfus Med, Ulm, Germany..
    Layrolle, Pierre
    Univ Nantes, Lab Bone Sarcomas & Remodeling Calcified Tissues, PHY OS, INSERM,UMR 1238,Fac Med, Nantes, France..
    Cell therapy induced regeneration of severely atrophied mandibular bone in a clinical trial2018Ingår i: Stem Cell Research & Therapy, E-ISSN 1757-6512, Vol. 9, artikel-id 213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Autologous grafting, despite some disadvantages, is still considered the gold standard for reconstruction of maxillofacial bone defects. The aim of this study was to evaluate bone regeneration using bone marrow-derived mesenchymal stromal cells (MSCs) in a clinical trial, a less invasive approach than autologous bone grafting. This comprehensive clinical trial included subjects with severe mandibular ridge resorption. Methods: The study included 11 subjects aged 52-79 years with severe mandibular ridge resorption. Bone marrow cells were aspirated from the posterior iliac crest and plastic adherent cells were expanded in culture medium containing human platelet lysate. The MSCs and biphasic calcium phosphate granules as scaffolds were inserted subperiosteally onto the resorbed alveolar ridge. After 4-6 months of healing, new bone formation was assessed clinically and radiographically, as were safety and feasibility. Bone at the implant site was biopsied for micro computed topography and histological analyses and dental implants were placed in the newly regenerated bone. Functional outcomes and patient satisfaction were assessed after 12 months. Results: The bone marrow cells, expanded in vitro and inserted into the defect together with biphasic calcium phosphate granules, induced significant new bone formation. The regenerated bone volume was adequate for dental implant installation. Healing was uneventful, without adverse events. The patients were satisfied with the esthetic and functional outcomes. No side effects were observed. Conclusions: The results of this comprehensive clinical trial in human subjects confirm that MSCs can successfully induce significant formation of new bone, with no untoward sequelae. Hence, this novel augmentation procedure warrants further investigation and may form the basis of a valid treatment protocol, challenging the current gold standard.

  • 143.
    Glier, Tomke E.
    et al.
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Akinsinde, Lewis
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Paufler, Malwin
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Otto, Ferdinand
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Hashemi, Maryam
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Grote, Lukas
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Daams, Lukas
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Neuber, Gerd
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Grimm-Lebsanft, Benjamin
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Biebl, Florian
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Rukser, Dieter
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Lippmann, Milena
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Ohm, Wiebke
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Schwartzkopf, Matthias
    DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Brett, Calvin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik.
    Matsuyama, Toru
    Max Planck Inst Struct & Dynam Matter, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Ruebhausen, Michael
    Univ Hamburg, Inst Nanostruktur & Festkorperphys, Ctr Free Electron Laser Sci CFEL, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Functional Printing of Conductive Silver-Nanowire Photopolymer Composites2019Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikel-id 6465Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigated the fabrication and functional behaviour of conductive silver-nanowire-polymer composites for prospective use in printing applications. Silver-nanowires with an aspect ratio of up to 1000 were synthesized using the polyol route and embedded in a UV-curable and printable polymer matrix. Sheet resistances in the composites down to 13 Omega/sq at an optical transmission of about 90% were accomplished. The silver-nanowire composite morphology and network structure was investigated by electron microscopy, atomic force microscopy, profilometry, ellipsometry as well as surface sensitive X-ray scattering. By implementing different printing applications, we demonstrate that our silver nanowires can be used in different polymer composites. On the one hand, we used a tough composite for a 2D-printed film as top contact on a solar cell. On the other hand, a flexible composite was applied for a 3D-printed flexible capacitor.

  • 144.
    Goliszek, M.
    et al.
    Marie Curie Sklodowska Univ, Fac Chem, Maria Curie Sklodowska Sq 3, PL-20031 Lublin, Poland..
    Podkoscielna, B.
    Marie Curie Sklodowska Univ, Fac Chem, Maria Curie Sklodowska Sq 3, PL-20031 Lublin, Poland..
    Fila, K.
    Marie Curie Sklodowska Univ, Fac Chem, Maria Curie Sklodowska Sq 3, PL-20031 Lublin, Poland..
    Riazanova, A. V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Aminzadeh, Selda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sevastyanova, O.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Gun'ko, V. M.
    Chuiko Inst Surface Chem, 17 Gen Naumov Str, UA-03164 Kiev, Ukraine..
    Synthesis and structure characterization of polymeric nanoporous microspheres with lignin2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 10, s. 5843-5862Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanoporous microspheres with divinylbenzene (DVB), styrene (St), and lignin were synthesized by an emulsion-suspension polymerization method. Several types of lignins were used: (1) kraft lignin before (L-unmod) and after modification with methacryloyl chloride (L-Met) and (2) low-molecular-weight kraft lignin unmodified (LWL-unmod) and modified with methacrylic anhydride (LWL-Met). LWL was prepared by ultrafiltration of industrial black liquor using a ceramic membrane with a molecular weight (Mw) cut-off of 5 kDa. The synthesis was optimized by addition of different amounts of lignins. The microsphere texture was characterized using low-temperature nitrogen adsorption and small angle X-ray scattering analyses. The microspheres were nano- and mesoporous with a specific surface area in the range of 0.1-409 m(2)/g. The morphology of the copolymers was studied using field emission scanning electron microscopy and atomic force microscopy. The thermal properties were studied using differential scanning calorimetry and thermogravimetric analysis methods. A significant difference in the microsphere roughness is affected by lignins due to the presence of lignin nanoparticles at the surface of the microspheres. Molecular modeling was used to predict the sorption properties of the copolymers affected by various fields around the particles. The particle size, polydispersity and zeta potential of the St + DVB, L-Met + St + DVB and L-unmod + St + DVB samples were measured by dynamic light scattering. Additionally, the point of zero charge of the samples was determined using potentiometric titration. The materials studied have a great potential for sorption processes due to their developed porosity and the presence of a number of active surface functionalities. [GRAPHICS] .

  • 145.
    Goliszek, M.
    et al.
    Marie Curie Sklodowska Univ, Dept Polymer Chem, M Curie Sklodowska Sq 5, PL-20031 Lublin, Poland..
    Podkoscielna, B.
    Marie Curie Sklodowska Univ, Dept Polymer Chem, M Curie Sklodowska Sq 5, PL-20031 Lublin, Poland..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Fila, K.
    Marie Curie Sklodowska Univ, Dept Polymer Chem, M Curie Sklodowska Sq 5, PL-20031 Lublin, Poland..
    Chabros, A.
    Marie Curie Sklodowska Univ, Dept Polymer Chem, M Curie Sklodowska Sq 5, PL-20031 Lublin, Poland..
    Paczkowski, P.
    Marie Curie Sklodowska Univ, Dept Polymer Chem, M Curie Sklodowska Sq 5, PL-20031 Lublin, Poland..
    Investigation of accelerated aging of lignin-containing polymer materials2019Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 123, s. 910-922Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the results of an accelerated aging test of biocomposites containing kraft lignin, where the resistance of the materials against humidity and light exposure was investigated. Low molecular weight lignin, modified with methacrylic anhydride (LWL-Met), was copolymerized with two commercial monomers: styrene (St) and methyl methacrylate (MMA). The biocomposites were obtained by a bulk polymerization method using alpha,alpha'-azoiso-bis-butyronitrile (AIBN) as a free radical polymerization initiator. The Shore D hardness of the obtained materials was determined before and after aging test. The changes in the chemical structures of polymers, as the result of aging were analyzed by using the attenuated total reflection Fourier transform infrared (ATR/FT-IR) spectroscopy method. The thermal behavior and stability of the obtained materials were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The surface topography was determined using the optical topography method to evaluate the changes on the surface of synthesized materials resulted from accelerated aging. Application of modified lignin as a biocomponent in the polymerization process and its influence on the properties of the obtained materials before and after the accelerated aging test are discussed.

  • 146.
    Granskog, Viktor
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Thiol-Ene/Yne Adhesives for Tissue Fixation2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Användningen av lim inom kirurgin har ännu inte nått sin fulla potential och kirurgernas önskan om förbättrade alternativ till dagens metoder för vävnadsfixering uppmuntrar till forskning inom området. I det här arbetet har reaktioner mellan tiolgrupper och kol-kol dubbel- (TEC) eller trippelbindningar (TYC) använts för att utveckla vävnadslim som härdar snabbt via fotoinitiering. För att göra säkra lim har makromolekylära limkomponenter och system med hög omsättning av funktionella grupper utvecklats för att minimera läckage av oreagerade monomerer.För att utveckla makromolekylära limkomponenter som utnyttjar de reologiska egenskaperna från dendritiska strukturer, syntetiserades allylfunktionella dendritisk-linjär-dendritiska (DLD) sampolymerer med ett mittsegment av poly (etylenglykol) (PEG) och hyperförgrenade strukturer av 2,2-bis (hydroximetyl) propionsyra syra (bis-MPA). De dendritiska strukturerna hindrade kristallisationen av PEG-segmentet och flytande polymerer erhölls som kunde användas som limkomponenter utan lösningsmedel. DLD komponenterna härdade snabbt med hjälp av en tioltvärbindare, vilket resulterade i nedbrytbara lim för mjuk vävnad med god vidhäftning mot fuktig grishud.Musselinspirerade dopaminderivat utvärderades som adhesionsförhöjande primers för benlim. Genom att tillsätta NaOH i pirmerlösningarna ökade bindningsstyrkan för benlimmet. De högsta bindningsstyrkorna med hjälp av dopaminederivaten erhölls när tiolderivat och derivat med dubbelbindningar användes tillsammans.Med inspiration från dentallim utvecklades ett helt TEC baserat limsystem med utmärkt adhesion till våta bensubstrat. Limsystemet möjliggjorde fixering av falangfraktursmodeller som presterade bättre än fixeringar med Kirschnerstift som används dagligen för frakturfixering. Dessutom kunde limmet även konkurrera med en skruvfixerad metallplatta. Limmaterialet visade sig vara biokompatibelt vid initiala in vitro och in vivo studier.För att göra starka och styva material för frakturfixeringar utvecklades tätt tvärbundna material baserade på triazin-trion (TATO) monomerer via TEC eller TYC-kemi. Utvecklingen resulterade i material med mekaniska egenskaper som mycket väl kan konkurrera med poly(etereterketon) (PEEK) som används i lastbärande biomedicinska applikationer på grund av sin goda hållfasthet och stabilitet i fysiologisk miljö.

  • 147.
    Granskog, Viktor
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi.
    Garcia-Gallego, Sandra
    KTH.
    von Kieseritzky, Johanna
    Karolinska Inst, Stockholm, Sweden..
    Pettersson, Jennifer
    RISE Res Inst Sweden, Boras, Sweden..
    Stenlund, Patrik
    RISE Res Inst Sweden, Boras, Sweden..
    Zhang, Yuning
    KTH.
    Petronis, Sarunas
    RISE Res Inst Sweden, Boras, Sweden..
    Lyven, Benny
    RISE Res Inst Sweden, Boras, Sweden..
    Arner, Marianne
    Karolinska Inst, Stockholm, Sweden..
    Hakansson, Joakim
    RISE Res Inst Sweden, Boras, Sweden..
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    High-performance and biocompatible thiol-ene based adhesive for bone fracture fixation2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 148.
    Granskog, Viktor
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    García-Gallego, Sandra
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    von Kieseritzky, Johanna
    Department of Clinical Science and Education and the Department of Hand Surgery, Karolinska Institutet.
    Rosendahl, Jennifer
    RISE Research Institutes of Sweden, Bioscience and Materials–Medical Device Technology.
    Stenlund, Patrik
    RISE Research Institutes of Sweden, Bioscience and Materials–Medical Device Technology.
    Zhang, Yuning
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Petronis, Sarunas
    RISE Research Institutes of Sweden, Bioscience and Materials–Medical Device Technology.
    Lyvén, Benny
    RISE Research Institutes of Sweden, Bioscience and Materials–Medical Device Technology.
    Arner, Marianne
    Department of Clinical Science and Education and the Department of Hand Surgery, Karolinska Institutet.
    Håkansson, Joakim
    RISE Research Institutes of Sweden, Bioscience and Materials–Medical Device Technology.
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    High-Performance Thiol–Ene Composites Unveil a New Era of Adhesives Suited for Bone Repair2018Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, nr 26, artikel-id 1800372Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of adhesives for fracture fixation can revolutionize the surgical procedures toward more personalized bone repairs. However, there are still no commercially available adhesive solutions mainly due to the lack of biocompatibility, poor adhesive strength, or inadequate fixation protocols. Here, a surgically realizable adhesive system capitalizing on visible light thiol–ene coupling chemistry is presented. The adhesives are carefully designed and formulated from a novel class of chemical constituents influenced by dental resin composites and self-etch primers. Validation of the adhesive strengthis conducted on wet bone substrates and accomplished via fiber-reinforced adhesive patch (FRAP) methodology. The results unravel, for the first time, on the promise of a thiol–ene adhesive with an unprecedented shear bondstrength of 9.0 MPa and that surpasses, by 55%, the commercially available acrylate dental adhesive system Clearfil SE Bond of 5.8 MPa. Preclinical validation of FRAPs on rat femur fracture models details good adhesion to the bone throughout the healing process, and are found biocompatible not giving rise to any inflammatory response. Remarkably, the FRAPs are found to withstand loads up to 70 N for 1000 cycles on porcine metacarpal fractures outperforming clinically used K-wires and match metal plates and screw implants.

  • 149. Grunlan, J.
    et al.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Youngblood, J. P.
    Editorial: Green nanocomposites2014Ingår i: Green Materials, ISSN 2049-1220, E-ISSN 2049-1239, Vol. 2, nr 4, s. 161-162Artikel i tidskrift (Refereegranskat)
  • 150.
    Guo, Lifang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Li, Dongfang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lennholm, Helena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Zhai, H.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Structural and functional modification of cellulose nanofibrils using graft copolymerization with glycidyl methacrylate by Fe 2+ –thiourea dioxide–H 2 O 2 redox system2019Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, nr 8, s. 4853-4864Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract: To graft epoxy and ester functional groups onto cellulose nanofibrils (CNFs) and to overcome their poor hydrophobicity, we studied the modification of CNFs using graft copolymerization with glycidyl methacrylate (GMA) by a Fe 2+ –thiourea dioxide–H 2 O 2 initiator system (Fe 2+ –TD–H 2 O 2 ) in aqueous solution. The synthesized poly (GMA)-grafted CNF (CNF-g-PGMA) was characterized by FTIR, AFM, XRD, water contact angle, and TGA. GMA was successfully grafted onto the CNFs by Fe 2+ –TD–H 2 O 2 , the epoxy groups and ester groups of GMA were clearly present and intact in the CNF-g-PGMA, and TD is an important component of the initiator system under relatively mild graft conditions. CNF-g-PGMA may be an important intermediate because of its epoxy and ester functional groups. The main nanostructure of the CNFs was retained after graft copolymerization, and there were no obvious effects of graft copolymerization on the crystalline structure of the CNF backbone, although the crystalline index slightly decreased with the increased percentage of grafting. Graft copolymerization significantly modifies the CNF hydrophobicity. This strategy could extend the applications of CNFs into many areas. Graphical abstract: [Figure not available: see fulltext.]

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