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  • 1.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lin, Chia-feng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, no 8, p. 11105-11114Article in journal (Refereed)
    Abstract [en]

    Functional carbon materials produced through a hydrothermal treatment of waste products have gained interest. Particularly, the method is considered more facile and green compared to conventional decomposition methods. Here, we demonstrated an upcycling of polypropylene (PP) waste to carbon materials by a microwave assisted hydro thermal treatment. The solid product obtained from the hydrothermal treatment was analyzed by multiple techniques to reveal the structure and the influence of processing conditions on PP degradation and hydrothermal carbonization. Chemical analyses showed the presence of carbonaceous material independent of acid amount (20 and 30 mL), temperature (210 and 250 degrees C), and time (20-80 min). A complete transformation of PP content to amorphous carbon required 60 min at 250 degrees C. The mass yield of the solid product decreased as a function of harsher processing conditions. At the same time, thermogravimetric analysis illustrated products with increasing thermal stability and a larger amount of remaining residue at 600 degrees C. The solid products consisted of irregular fragments and sheet-like structures. A solid state microwave process in air atmosphere was performed on a product with incomplete carbonization. The modification resulted in a decreased C/O ratio, and TGA analysis in nitrogen showed high thermal stability and degree of carbonization as indicated by the remaining residue of 86.4% at 600 degrees C. The new insights provided on the hydrothermal carbonization, and postmodification in air atmosphere, can catalyze effective handling of plastic waste by enabling transformation of low quality waste into functional carbon materials.

  • 2.
    Benyahia Erdal, Nejla
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Green Strategy to Reduced Nanographene Oxide through Microwave Assisted Transformation of Cellulose2018In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 1, p. 1245-1255Article in journal (Refereed)
    Abstract [en]

    A green strategy for fabrication of biobased reduced nanographene oxide (r-nGO) was developed. Cellulose derived nanographene oxide (nGO) type carbon nanodots were reduced by microwave assisted hydrothermal treatment with superheated water alone or in the presence of caffeic acid (CA), a green reducing agent. The carbon nanodots, r-nGO and r-nGO-CA, obtained through the two different reaction routes without or with the added reducing agent, were characterized by multiple analytical techniques including FTIR, XPS, Raman, XRD, TGA, TEM, AFM, UV-vis, and DLS to confirm and evaluate the efficiency of the reduction reactions. A significant decrease in oxygen content accompanied by increased number of sp2 hybridized functional groups was confirmed in both cases. The synergistic effect of superheated water and reducing agent resulted in the highest C/O ratio and thermal stability, which also supported a more efficient reduction. Interesting optical properties were detected by fluorescence spectroscopy where nGO, r-nGO, and r-nGO-CA all displayed excitation dependent fluorescence behavior. r-nGO-CA and its precursor nGO were evaluated toward osteoblastic cells MG-63 and exhibited nontoxic behavior up to 200 μg mL-1, which gives promise for utilization in biomedical applications.

  • 3.
    Berglund, Lars
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Yang, Xuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Design of biodegradable cellulosic nanomaterials combining mechanical strength and optical transmittance2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 4.
    Erdal, Nejla B.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    De Lima, Sara
    Karolinska Inst, St Erik Eye Hosp, Div Ophthalmol & Vis, Dept Clin Neurosci, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    In vitro and in vivo effects of ophthalmic solutions on silicone hydrogel bandage lens material Senofilcon A2018In: Clinical and experimental optometry, ISSN 0816-4622, E-ISSN 1444-0938, Vol. 101, no 3, p. 354-362Article in journal (Refereed)
    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.

  • 5.
    Erdal, Nejla B.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Construction of Bioactive and Reinforced Bioresorbable Nanocomposites by Reduced Nano-Graphene Oxide Carbon Dots2018In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 3, p. 1074-1081Article in journal (Refereed)
    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.

  • 6.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Tunable chitosan hydrogels for adsorption: Property control by biobased modifiers2018In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 196, p. 135-145Article in journal (Refereed)
    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.

  • 7.
    Feng, Zhaoxuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Microwave carbonized cellulose for trace pharmaceutical adsorption2018In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 346, p. 557-566Article in journal (Refereed)
    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.

  • 8.
    Hua, Geng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Ring-opening Approaches to Functional Renewable Polymers2018Doctoral thesis, comprehensive summary (Other academic)
    The full text will be freely available from 2019-05-04 14:51
  • 9.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Design of renewable polymeric materials through ring-opening reactions2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 10. Ohm, Wiebke
    et al.
    Rothkirch, Andre
    Pandit, Pallavi
    Koerstgens, Volker
    Mueller-Buschbaum, Peter
    Rojas, Ramiro
    Yu, Shun
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Brett, Calvin J.
    Soderberg, Daniel L.
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Morphological properties of airbrush spray-deposited enzymatic cellulose thin films2018In: JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, ISSN 1945-9645, Vol. 15, no 4, p. 759-769Article in journal (Refereed)
    Abstract [en]

    We investigate the layer formation of enzymatic cellulose by airbrush spray coating on silicon oxide surfaces. The layer structure and morphology of enzymatic cellulose films in the thickness range between 86 nm and 2.1 A mu m is determined as a function of the spray coating procedures. For each spray coating step, layer buildup, surface topography, crystallinity as well as the nanoscale structure are probed with atomic force microscopy and surface-sensitive X-ray scattering methods. Without intermittent drying, the film thickness saturates; with intermittent drying, a linear increase in layer thickness with the number of spray pulses is observed. A closed cellulose layer was always observed. The crystallinity remains unchanged; the nanoscale structures show three distinct sizes. Our results indicate that the smallest building blocks increasingly contribute to the morphology inside the cellulose network for thicker films, showing the importance of tailoring the cellulose nanofibrils. For a layer-by-layer coating, intermittent drying is mandatory.

  • 11. Sharma, Sunita
    et al.
    Sapkota, Dipak
    Xue, Ying
    Rajthala, Saroj
    Yassin, Mohammed A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Wistrand, Anna Finne
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Mustafa, Kamal
    Delivery of VEGFA in bone marrow stromal cells seeded in copolymer scaffold enhances angiogenesis, but is inadequate for osteogenesis as compared with the dual delivery of VEGFA and BMP2 in a subcutaneous mouse model2018In: Stem Cell Research & Therapy, E-ISSN 1757-6512, Vol. 9, article id 23Article in journal (Refereed)
    Abstract [en]

    Background: In bone tissue engineering (BTE), extensive research into vascular endothelial growth factor A (VEGFA)-mediated angiogenesis has yielded inconsistent results. The aim of this study was to investigate the influence on angio-and osteogenesis of adenoviral-mediated delivery of VEGFA alone or in combination with bone morphogenetic protein 2 (BMP2) in bone marrow stromal cells (BMSC) seeded onto a recently developed poly(LLA-co-CL) scaffold. Methods: Human BMSC were engineered to express VEGFA alone or in combination with BMP2 and seeded onto poly(LLA-co-CL) scaffolds. Changes in angiogenic and osteogenic gene and protein levels were examined by quantitative reverse-transcription polymerase chain reaction (RT-PCR), PCR array, and alkaline phosphatase assay. An in vivo subcutaneous mouse model was used to investigate the effect on angio-and osteogenesis of VEGFA alone or in combination with BMP2, using microcomputed tomography (mu CT), histology, immunohistochemistry, and immunofluorescence. Results: Combined delivery of a lower ratio (1: 3) of VEGFA and BMP2 (ad-BMP2 + VEGFA) led to upregulation of osteogenic and angiogenic genes in vitro at 3 and 14 days, compared with mono-delivery of VEGFA (ad-VEGFA) and other controls. In vivo, in a subcutaneous mouse model, both ad-VEGFA and ad-BMP2 + VEGFA scaffold explants exhibited increased angiogenesis at 2 weeks. Enhanced angiogenesis was largely related to the recruitment and differentiation of mouse progenitor cells to the endothelial lineage and, to a lesser extent, to endothelial differentiation of the implanted BMSC. mu CT and histological analyses revealed enhanced de novo bone formation only in the ad-BMP2 + VEGFA group, corresponding at the molecular level to the upregulation of genes related to osteogenesis, such as ALPL, RUNX2, and SPP1. Conclusions: Although BMSC expressing VEGFA alone or in combination with BMP2 significantly induced angiogenesis, VEGFA alone failed to demonstrate osteogenic activity both in vitro and in vivo. These results not only call into question the use of VEGFA alone in bone regeneration, but also highlight the importance in BTE of appropriately formulated combined delivery of VEGFA and BMP2.

  • 12.
    Sterner, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Multicomponent fractionation of Saccharina latissima brown algae using chelating salt solutions2016In: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 28, no 4, p. 2561-2574Article in journal (Refereed)
    Abstract [en]

    A fractionation strategy for Saccharina latissima algal biomass was developed utilizing chelating extraction salt solutions to mediate the liberation of algal components. Alginate, cellulose, laminarin, mannitol, protein, and inorganic salts were quantified in the fractions to reveal their individual dissolution patterns. Chelation power was identified as a key parameter for liberating alginate and increasing the yield of extracted components. The most efficient fractionation was achieved using aqueous sodium citrate as the extraction solution, producing an alginate-rich soluble fraction and a salt-poor insoluble fraction rich in cellulose and protein. Extractions at decreased pH were shown to be beneficial because they decreased the M/G ratio of the extracted alginate and concentrated the protein in the insoluble fraction from which it can easily be recovered; these effects could be achieved by switching the traditional sodium carbonate extraction solution with salts that have chelation capacity at lower pH. A cyclic extraction demonstrated that the sodium citrate solution can be reused for multiple alginate extractions with the buildup of the concentrations of other valuable components in the solution.

  • 13.
    Sterner, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    POLYMER EXTRACTION AND UTILIZATION OF BROWN ALGAL BIOMASS2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Aquaculture is a field with a world changing potential. The areas at sea are enormous and aquatic cultivations impact both the environment and local ecology far less than land based cultivations. In the realm of algae, abundancies exists of nutrition, water and accessible sunlight, but there is constant shortage of places to dwell. In an algae farm, the algae are given free space to dwell on a seeding line, the growth is massive. In the Swedish research project Seafarm, which this work belongs to, a 4500 m long line gives 15 kg/m of Saccharina latissima brown algae in each harvest. This is a thesis on how to process the algal biomass and generate materials. The algal component alginate, which is a natural charged polymer, is the main thread along the entire thesis, both in the beginning, when focus lies on extraction and in the end when alginate materials are made.

    In an algal extraction-study the impact of chelation-strength parameter was assessed. Salts with different ability to chelate ions were used in the extraction process, sodium citrate was found to be the most promising extraction salt to liberate alginate.

    A cyclic process, in which a sodium citrate solution was regenerated and reused, was developed and assessed. An interesting effect of the new process was that it allowed for a fractionation of alginate into several qualities with different uronic acid composition (the two building blocks of alginate). This fractionation was scaled up to supply enough alginate to support a material study to evaluate the individual properties of the different fractions.

    Alginate gel filaments were made by extruding alginate into calcium chloride solution, in which if forms gels. Certain gels were also exposed to aluminum chloride. The filaments were tested for their tensile properties. An interesting trend in the relation between gel strength and uronic acid composition also inspired a theoretical study to establish the mechanism behind the observed trends. Gel-filaments were drawn in solutions of different alginate interacting salts, then dried into thin filaments and subjected to tensile testing. The treatments increased the modulus of the filaments and also increased their stress-at-break. The tensile properties were comparable to that of other natural derived fibers such as hemp fiber or cotton cellulose.

    Compatibilizers were developed to tune the surface energy of the filaments and approach that of polymers used in fiber reinforced composites. The compatibilizers were made of linseed oil that was grafted with maleic anhydride to attach charged groups. The graft modified oil was added to alginate filaments which were tensile-tested.

    The full text will be freely available from 2019-06-24 13:37
  • 14.
    Sterner, Martin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Alginate with maleic anhydride grafted linseed oil as compatibilizerManuscript (preprint) (Other academic)
    Abstract [en]

    Linseed oil was graft modified with maleic anhydride and introduced into alginate by coextrusion,producing filaments which are targeted to work as interphase compatibilizersbetween alginate and hydrophobic matrices. Modified oil was produced by a straightforwardair catalyzed radical chemistry based grafting of maleic anhydride onto the oil backbone.Additional esterification with dodecanol was also investigated. The structures of the modifiedoils were verified with 2D-NMR. Modified oil was blended with alginate and extruded intoCaCl2 forming thin filaments with diameters in the 130 - 260 m range. The impact of oilintegration into the alginate filaments and the effects of various modification chemistries onthe filament tensile properties were assessed with special emphasis on stress-at-break andcompared to values predicted by an empirical model relating the ‘stress to alginateconcentration’-ratio to prevailing conditions during filament drawing. Analogous alginatefilaments were prepared with chloric-, oxalic- and phytic acid calcium salts for comparisonwith alginate-oil hybrids to reveal the induced impact, with respect to composition andcharge, on the tensile performance.

  • 15.
    Wahlström, Niklas
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Harrysson, H.
    Undeland, I.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    A Strategy for the Sequential Recovery of Biomacromolecules from Red Macroalgae Porphyra umbilicalis Kützing2018In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 57, no 1, p. 42-53Article in journal (Refereed)
    Abstract [en]

    A nondestructive, multicomponent fractionation strategy has been developed to extract proteins and polysaccharides from the red macroalgae Porphyra umbilicalis collected along the west coast of Sweden and cultivated indoors under controlled conditions. First, a protein-rich fraction was extracted in an ice-cold alkaline solution. The overall protein content in Porphyra umbilicalis was estimated to be 30.6% of the dry weight, and out of that, 15.0% could be recovered. Water-soluble polysaccharides were then extracted from the insoluble residual fraction using sequential alkaline and acidic treatments at 90 °C for 4 h. Spectroscopic and chromatographic analyses of the polysaccharide fractions show that high-molecular-weight carrageenans were obtained from the alkaline extraction and a galactose-rich pectin substance was obtained from the acidic extraction. The insoluble fraction remaining after all extraction steps was rich in cellulose. An elemental analysis of Porphyra umbilicalis via scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDS) showed the presence of C, O, Na, Ca, Mg, Al, Cl, and S. However, no heavy metals or other toxic elements, such as Pb, Hg, and As, were found.

  • 16.
    Wu, Duo
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Samanta, A.
    Srivastava, R. K.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Nano-graphene oxide functionalized bioactive poly(lactic acid) and poly(ε-caprolactone) nanofibrous scaffolds2018In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 11, no 4, article id 566Article in journal (Refereed)
    Abstract [en]

    A versatile and convenient way to produce bioactive poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) electrospun nanofibrous scaffolds is described. PLA and PCL are extensively used as biocompatible scaffold materials for tissue engineering. Here, biobased nano graphene oxide dots (nGO) are incorporated in PLA or PCL electrospun scaffolds during the electrospinning process aiming to enhance the mechanical properties and endorse osteo-bioactivity. nGO was found to tightly attach to the fibers through secondary interactions. It also improved the electrospinnability and fiber quality. The prepared nanofibrous scaffolds exhibited enhanced mechanical properties, increased hydrophilicity, good cytocompatibility and osteo-bioactivity. Therefore, immense potential for bone tissue engineering applications is anticipated.

  • 17.
    Xu, Yunsheng
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hua, Geng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Odelius, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Isosorbide as Core Component for Tailoring Biobased Unsaturated Polyester Thermosets for a Wide Structure- Property Window2018In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 7, p. 3077-3085Article in journal (Refereed)
    Abstract [en]

    Biobased unsaturated polyester thermosets as potential replacements for petroleum-based thermosets were designed. The target of incorporating rigid units, to yield thermosets with high thermal and mechanical performance, both in the biobased unsaturated polyester (UP) and reactive diluent (RD) while retaining miscibility was successfully achieved. The biobased unsaturated polyester thermosets were prepared by varying the content of isosorbide, 1,4-butanediol, maleic anhydride, and succinic anhydride in combination with the reactive diluent isosorbide-methacrylate (IM). Isosorbide was chosen as the main component in both the UP and the RD to enhance the rigidity of the formed thermosets, to overcome solubility issues commonly associated with biobased UPs and RDs and volatility and toxicity associated with styrene as RD. All UPs had good solubility in the RD and the viscosity of the mixtures was primarily tuned by the feed ratio of isosorbide but also by the amount of maleic anhydride. The flexural modulus and storage modulus were tailorable by altering the monomer composition The fabricated thermosets had superior thermal and mechanical properties compared to most biobased UP thermosets with thermal stability up to about 250 degrees C and a storage modulus at 25 degrees C varying between 0.5 and 3.0 GPa. These values are close to commercial petroleum-based UP thermosets. The designed tailorable biobased thermosets are, thus, promising candidates to replace their petroleum analogs.

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