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  • 301.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Burman, Lina
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Chromatographic Analysis and Total Luminescence Intensity as Tools for Early Degradation Detection and Degradation State Estimation2006Inngår i: ACS Symposium Series: Degradable Polymers and Materials, Principles and Practice / [ed] Kishan Khemani and Carmen Scholz, American Chemical Society (ACS), 2006, 1, s. 307-319Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Indicator product concept, chromatographic fingerprinting in combination with multivariate data analysis and total luminescence intensity (TLI) are presented as tools for product evaluation, quality control and testing of degradable polymers. A correlation was shown between the number of chain scission and the release of dicarboxylic acids during photo-and thermo-oxidation of polyethylene. This opens for degradation state prediction from the amount of indicator products released. Multivariate data analysis of chromatographic fingerprints of dicarboxylic acids allowed classification of polyethylene materials both with respect to the degradation state and pro-oxidant system. Total luminescence intensity proved to be an excellent tool for early degradation detection and classification of polyethylene materials. Further applications could include classification of materials with respect to durability or degradability, evaluation of antioxidant or pro-oxidant

  • 302.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Update on polylactide based materials2011 (oppl. 1)Bok (Annet vitenskapelig)
    Abstract [en]

    Today both scientists and industry are working to develop more environmentally friendly processes and materials. One of the most current topics is the development of energy and materials from renewable resources. There are fascinating developments in this area and advanced designed products can today be formed in an environmentally friendly way. Polylactide based materials are among the most promising synthetic renewable resource based materials. There is currently extensive research going on to develop polylactide based materials for different applications. These developments include both the use of new resources, development of more effective and environmentally friendly processes as well as modification and tailoring of material properties and degradability to broaden the application range.

    This book discusses recent developments in polylactide based materials including the whole spectra from different material modifications, applications and properties to new advanced synthesis procedures. When it comes to degradable materials, an important aspect is also the influence of different modifications on material properties, degradability and degradation products. The different chapters present new emerging processes and synthetic techniques as well as different material modifications obtained by copolymerization or blending with degradable or inert, natural or synthetic polymers. In addition advancements and developments in polylactide stereocomplexes, nanocomposites and biocomposites are presented. The book is of interest both from the basic and applied science point of view as it presents the latest trends and demonstrates the versatility and great potential of polylactide based materials. Hopefully the book can inspire the reader to further develop synthesis procedures or new ways to modify polylactide materials to broaden the properties to suit new applications.

  • 303.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Gallet, Guillaume
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Prediction by multivariate data analysis of long-term properties of glassfiber reinforced polyester composites1999Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 64, s. 91-99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The prediction of long-term properties of polymers has been analysed by identifiction of low molecular weight compounds in glassfibre-reinforced polyester composites which were subjected to accelerated ageing at 40 and 60 degrees C and 80 %-RH for periods up to 6 years. Before the accelerated ageing the materials were stored for 20 years at ambient temperature. After different ageing times the low molecular weight products in the materials were identified with GC-MS and headspace-GC-MS. Several different alcohols, phthalates and other aromatic compounds were identified. Temperature had a large influence on the degradation of phthalates and the formation of alcohols. In the first step we used principal component analysis (PCA) and partial least square (PLS) to locate outliers and to identify the products that were not connected to degradation time or temperature. After that PCA and PLS were used to reveal if unsaturated polyesters have different degradation mechanisms at 40 and 60 degrees C by comparing the amounts and types of degradation products. The relative influence of each factor on the degradation rate was studied and groups were made among the degradation products to define which degradation products are correlated with ageing time and temperature. Finally the ageing time was predicted from the amounts of degradation products (in that case the amount of products are considered as X factors and the time of degradation as a Y response). PCA showed that it was not possible to find a pattern in the HS-GC-MS chromatograms, due to the different volatility of the compounds. The score plots revealed the existence of domains which depended on the degradation temperature. Some of the compounds (diethyl phthalate, 2-propenyl ester of bensoic acid and bensoic acid) could not be predicted by the models. These products are not related to the degradation of the material itself. At 60 degrees C, 80% RH in air, PLS models showed a good correlation between amount of identified products and degradation time and it was possible to estimate the degradation time directly from the quantity of the 13 identified degradation products.

  • 304.
    Hakkarainen, Minna
    et al.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Gröning, M.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner, Polymerteknologi.
    Solid-phase microextraction (SPME) in polymer characterization - Long-term properties and quality control of polymeric materials2003Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 89, nr 3, s. 867-873Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solid-phase microextraction (SPME) in combination with GG-MS was applied to quality control polyamide 6.6 collected for recycling and to study the long-term properties and degadation of nitrile rubber, polyethylene, and polyamide 6.6. The migration of plasticizer and other additives reduces the service-life and changes the properties of the material. It is also a possible health hazard, for example, legislation against the use of brominated flame retardants in plastic materials, is under discussion, and fast and reliable methods are required to detect such compounds in plastic materials collected for recycling. SPME rapidly and effectively extracted several brominated compounds from in-plant collected polyamide 6.6. Migration of tris(2-butoxy-ethyl)phosphate plasticizer and its degradation products from nitrile rubber during long-term thermal ageing at 60 and 80degreesC was shown by SPME-GC-MS, while the plasticizer was not volatile enough to be detected by traditional HS-GC-MS. In accordance the number of degradation products extracted from thermo-oxidized PE by HS-SPME was three times larger than the number detected after HS-GC-MS analysis. SPME-GC-MS could also detect early signs of degradation in thermo-oxidized virgin and in-plant recycled polyamide 6.6 before any signs of degradation were observed by, for example, tensile testing or FTIR.

  • 305.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Höglund, Anders
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Tuning the release rate of acidic degradation products through macromolecular design of caprolactone-based copolymers2007Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, nr 19, s. 6308-6312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macromolecular engineering is presented as a tool to control the degradation rate and release rate of acidic degradation products from biomedical polyester ethers. Three different caprolactone/1,5-dioxepan-2-one (CL/DXO) copolymers were synthesized: DXO/CL/DXO triblock, CL/DXO multiblock, and random cross-linked CL/DXO copolymer. The relation of CL and DXO units in all three copolymers was 60/40 mol %. The polymer discs were immersed in phosphate buffer solution at pH 7.4 and 37 degrees C for up to 364 days. After different time periods degradation products were extracted from the buffer solution and analyzed. In addition mass loss, water absorption, molecular weight changes, and changes in thermal properties were determined. The results show that the release rate of acidic degradation products, a possible cause of acidic microclimates and inflammatory responses, is controllable through macromolecular design, i.e., different distribution of the weak linkages in the copolymers.

  • 306.
    Hakkarainen, Minna
    et al.
    University of Helsinki, Finland.
    Jansson, Robert
    University of Helsinki, Finland.
    Sundholm, Francesca
    University of Helsinki, Finland.
    Liquid-Crystalline Behavior Of Some Carboxylic-Acids1993Inngår i: Polymer Bulletin, ISSN 0170-0839, E-ISSN 1436-2449, Vol. 31, nr 1, s. 43-48Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of 4-omega-carboxyalkoxyphenyl-4'-methoxybenzoates 2 underbar has been prepared. Compounds with a spacer length of n=3 and n=5 show liquid crystalline behaviour. The products were characterized by IR and H-1NMR -spectroscopy, mass spectrometry, optical microscopy and DSC -measurements. The compounds are potentially useful as side-groups in liquid-crystalline polymers.

  • 307.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Gas Chromatography in analysis of polymers and rubbers2000Inngår i: Encyclopedia of Analytical Chemistry / [ed] R.A. Meyers, John Wiley & Sons, 2000, s. 7608-7623Kapittel i bok, del av antologi (Fagfellevurdert)
  • 308.
    Hakkarainen, Minna
    et al.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner, Polymerteknologi.
    Influence of low molecular weight lactic acid derivatives on degradability of polylactide2000Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 76, nr 2, s. 228-239Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The presence of low molecular weight lactic acid derivatives in films enhanced the degradability of polylactide in a biotic medium. Two different biotic and abiotic series were investigated. The films used for the first abiotic and biotic series (a-l and b-1 films) initially contained some lactic acid and lactoyl lactic acid, while the films used for the second abiotic and biotic series (a-2 and b-2 films) did not originally contain them. The b-1 films decreased in molecular weight during 3 weeks in the biotic medium, while no molecular weight decrease was seen in the a-1 films aged in a corresponding abiotic mineral medium. The molecular weight for the a-2 and b-2 films without lactic and lactoyl lactic acid remained almost constant. Scanning electron microscopy micro-graphs showed a larger amount of bacteria and fungi growing on the surface of b-1 films compared to b-2 films; thus, the presence of easily assimilated lactic acid and lactoyl lactic acid in the films improved the initial growth of microorganisms on the film surfaces. Gas chromatography and mass spectrometry analysis showed that lactic acid and lactoyl lactic acid were rapidly assimilated from the films aged in a biotic medium. New degradation products (e.g., ethyl ester of lactoyl lactic acid, acetic acid, and propanoic acid) were formed during aging in a biotic medium. Acetic acid and propanoic acid were formed as intermediate degradation products during the initial stages, but they were no longer detected after prolonged aging. The concentration of the ethyl ester of lactoyl lactic acid increased with aging time.

  • 309.
    Hakkarainen, Minna
    et al.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner, Polymerteknologi.
    Rapid (bio)degradation of polylactide by mixed culture of compost microorganisms - low molecular weight products and matrix changes2000Inngår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 41, nr 7, s. 2331-2338Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Poly(L-lactide) (PLLA) was rapidly (bio)degraded by a mixed culture of compost microorganisms. After 5 weeks in biotic environment, the films had fragmented to fine powder, while the films in corresponding abiotic medium still looked intact. Analysis of the low molecular weight products by GC-MS showed that microorganisms rapidly assimilated lactic acid and lactoyl lactic acid from the films. At the same time, a new degradation product, ethyl ester of lactoyl lactic acid was formed in the biotic environment. This product cannot be formed by abiotic hydrolysis and it was not detected in the abiotic medium. The degradation of the PLLA matrix was monitored by differential scanning calorimetry (DSC), size exclusion chromatography (SEC) and scanning electron microscopy (SEM). A rapid molecular weight decrease and increasing polydispersity was observed in the biotic environment. In the abiotic environment only a slight molecular weight decrease was seen and the polydispersity started decreasing towards 2.0. This indicates different degradation mechanisms, i.e. preferred degradation near the chain ends in the biotic environment and a random hydrolysis of the ester bonds in the abiotic environment. SEM micrographs showed the formation of patterns and cracks on the surface of the films aged in biotic medium, while the surface of the sterile films remained smooth. The SEM micrographs showed a large number of bacteria and mycelium of fungi growing on the surface of the biotically aged films.

  • 310.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Khabbaz, Farideh
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Biodegradation of polyethylene followed by assimilation of degradation products2003Inngår i: Biopolymers: Volume 9: Miscellaneous Biopolymers and Biodegradation of synthetic Polymers / [ed] Alexander Steinbüchel, Wiley-VCH Verlagsgesellschaft, 2003, s. 369-394Kapittel i bok, del av antologi (Fagfellevurdert)
  • 311.
    Hallberg, Christofer
    KTH, Skolan för kemivetenskap (CHE).
    Waterborne Coatings for Pre-Treated Pine Substrates - Adhesion Performance and Durability2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Coatings designed for exterior wood constructs have the important functions to give an aesthetically acceptable surface appearance and provide a long-term protection protective against environmental factors. The most important criterion for long-term performance of these coatings is good adhesion to its wooden substrate. The adhesion performance of a coating depends on its ability to mechanical and chemical adhere to the wood substrate. The chemical adhesion is primarily dependent on the chemical nature of the binder system in the coating formulation and its ability to form chemical interactions between the coating and the wood surfaces. In contrast, the mechanical adhesion is primarily dependent on the penetration ability of the coating into micro-pores and irregularities of the surface of the wood. Thus, the mechanical adhesion is often referred to as the mechanical interlocking effect, or the mechanical anchoring effect. An assessment of the impact of these on the adhesion performance of wood coatings is of great importance. Such an assessment has been issued by the Swedish-based company OrganoClick located in Täby, Sweden. Previous observations made by the company has indicated that waterborne coatings are prone to adhesion failure prior to the expected service life when applied to impregnated pine substrates. For this assessment, five waterborne coatings based on four different polymeric binder systems were prepared; two acrylic-based binders, a polyurethane-acrylic-based binder, and an alkyd-based binder. The chemical composition of these four binder systems was determined by Fourier transform infrared spectrometry. The experiment showed that the chemical adhesion of the waterborne coatings most likely was dependent on secondary interactions, in particularly hydrogen bonding between carbonyl groups in the backbone structures of these resins, and the high abundance of surface exposed hydroxyl groups of the pine substrate. Fourier transform infrared spectrometry showed the presence of X on the surface of the impregnated pine substrates. These substrates were then further investigated with scanning electron microscopy and energy-dispersive X-ray spectrometry, which showed the presence of an X-containing residue filling the voids of the near-surface tracheids in these pine substrates. This confirmed the finding from the Fourier transform infrared spectrometry i.e. that the residue on the surfaces of these impregnated pine substrates was X. Consequently, the waterborne coatings could not penetrate into the voids of the near-surface tracheids and establish mechanical adhesion to their pine substrates through mechanical interlocking/anchoring. However, the acrylic-based coating X showed some degree of penetration into the tracheids of the impregnated pine substrate. 

    The adhesion performance and durability of the five waterborne coatings were evaluated by means of a four month long natural weathering experiment (28/4 – 12/9). The result from the natural weathering experiment of the coated impregnated pine substrates was compared with the results from a second natural weathering experiment performed in parallel. This second natural weathering experiment included coated untreated substrates, coated detergent post-treated substrates, and coated pine substrates which had been subjected to an accelerated aging process (EN 84:1997). The polyurethane-acrylic coating demonstrated poor overall adhesion performance on all pine substrate types, except the post-treated substrate, as it delaminated from its pine substrates. Delamination was especially evident on the impregnated substrate. This was likely to be a combined consequence of inhomogeneous pigment distribution of titanium dioxide particles and pigment agglomeration, the presence of extensive cratering surface defects, and the lack of mechanical adhesion of the coating to its pine substrate. The presence of extensive cratering defects was believed to have the greatest negative impact on the overall adhesion performance of this waterborne coating since the cratering defects significantly increase the risk of moisture penetration through the coating layers. Additionally, the hydrophilic character of the urethane linkage was believed to further intensify this effect. However, the coated detergent post-treated pine substrates demonstrated significantly better adhesion performance compared to the other coated substrate types. Thus, the detergent wash had a positive effect on the adhesion performance of the coating by removing a significant portion of the X residues from the surface of the impregnated pine substrates. The acrylic-based reference coating based on the polymeric binder had extensive pinhole defects on the surface of its coating film. This defect was believed to have a similar negative effect on the adhesion performance of this coating as the effects from the cratering defects found on the polyurethane-acrylic coating. In contrast, the two acrylic-based coatings and the alkyd-based coating demonstrated good adhesion performance on all pine substrate types up to the specified point of exposure to natural weathering. A plausible explanation of this difference in adhesion performance was most likely the absence of extensive surface coating defects. However, the lack of mechanical adhesion will likely lead to adhesion failure of these waterborne coatings from their impregnated pine substrates after a longer exposure to natural weathering.

  • 312.
    Halysh, Vita
    et al.
    Igor Sikorsky Kyiv Polytech Inst, Fac Chem Engn, Dept Ecol & Technol Plant Polymers, Peremogy Avenu 37-4, UA-03056 Kiev, Ukraine.;Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Riazanova, Anastasia 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.
    Pasalskiy, Bogdan
    Kyiv Natl Univ Trade & Econ, Kyoto Str 19, UA-02156 Kiev, Ukraine..
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Kartel, Mykola
    Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Walnut shells as a potential low-cost lignocellulosic sorbent for dyes and metal ions2018Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 8, s. 4729-4742Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, it is necessary to develop new methods and materials for solving the problem of environmental pollution by various toxicants. For these purposes, vegetal materials can be used. In this study, efficient low-cost sorbents based on walnut shells, an agro-industrial by-product, were prepared by treatment with acetic acid or a mixture of acetic acid and hydrogen peroxide. It was shown that the treatments significantly affected the composition and structure of walnut shells and their sorption properties with respect to organic dyes (methylene blue, methyl violet, and murexide) and heavy metal ions. Methylene blue dye was used for additional studies on the effect of pH, contact time and kinetics of sorption. The maximum adsorption rate of the dye occurred within the first 30 min of contact, during which the concentration of methylene blue in the solution was reduced by more than half. Full sorption equilibrium was reached within 180-230 min for studied samples. The adsorption kinetics of methylene blue was found to best be described by pseudo-second-order kinetic model. It was shown that dyes adsorption processes were well described by Freundlich model, which takes into consideration the heterogeneity of the surface of the adsorbent. The obtained plant sorbents are characterized by a high sorption capacity for heavy metal ions (18-29 mg/g for Fe3+ and 33-44 mg/g for Cu-2). Due to their numerous advantages, such as the high sorption capacity, high availability and low cost of raw materials, simplicity of disposal and nontoxicity, the obtained natural sorbents may have a wide practical use in industrial wastewater treatment. [GRAPHICS] .

  • 313. Hammarling, L.
    et al.
    Gustavsson, H.
    Svensson, K.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Oskarsson, A.
    Migration of epoxidizied soya bean oil from plasticized PVC gaskets into baby food1997Inngår i: Food Addities and ContaminantsArtikkel i tidsskrift (Fagfellevurdert)
  • 314. Hansen, Natanya M. L.
    et al.
    Blomfeldt, Thomas O. J.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Plackett, David V.
    Properties of plasticized composite films prepared from nanofibrillated cellulose and birch wood xylan2012Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 19, nr 6, s. 2015-2031Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Xylans, an important sub-class of hemicelluloses, represent a largely untapped resource for new renewable materials derived from biomass. As with other carbohydrates, nanocellulose reinforcement of xylans is interesting as a route to new bio-materials. With this in mind, birch wood xylan was combined with nanofibrillated cellulose (NFC) and films were cast with and without glycerol, sorbitol or methoxypolyethylene glycol (MPEG) as plasticizers. Microscopy revealed some NFC agglomeration in the composite films as well as a layered nanocellulose structure. Equilibrium moisture content in plasticized films increased with glycerol content but was independent of xylan:NFC ratio in unplasticized films. Sorbitol- and MPEG-plasticized films showed equilibrium moisture contents of approximately 10 wt% independent of plasticizer content. Tensile testing revealed increases in tensile strength with increased NFC content in the xylan:NFC composition range from 50:50 to 80:20 and plasticizer addition generally provided less brittle films. The oxygen permeability of unplasticized xylan-NFC films fell into a range which was similar to that for previously measured pure NFC films and was statistically independent of the xylan:NFC ratio. Water vapor permeability values of 1.9-2.8.10(-11) g Pa-1 m(-1) s(-1) were found for unplasticized composite films, but these values were significantly reduced in the case of films plasticized with 10-40 wt% sorbitol.

  • 315. Hansson, E.
    et al.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Multiple headspace single-drop microextraction - a new technique for quantitative determination of styrene in polystyrene2006Inngår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1102, nr 1-2, s. 91-95Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single-drop microextraction (SDME), an emerging miniaturised extraction technique, was for the first time combined with multiple headspace extraction (MHE) to enable the quantitative determination of volatiles in solid matrixes by SDME technique. The concept of multiple headspace single-drop microextraction (MHS-SDME) was then applied for quantitative determination of styrene in polystyrene (PS) samples. Good linearity for the multiple headspace extraction was obtained when the migration of styrene was facilitated by grinding the samples and incubating them for 1 h at 150 degrees C prior the first extraction. Two microlitres of butyl acetate was used as the single-drop microextraction solvent and the extraction time was 5 min per cycle. The relative standard deviation (RSD) for single-drop microextraction of styrene standard at n = 6 was 7.6%. Linearity was shown for styrene concentrations between 0.005 and 0.75 mu g/ml (R-2 = 0.999). This corresponds to total amount of styrene between 0.1 and 15 mu g. The limit of quantitation for styrene standard at S/N 10 was 0.005 mu g/ml. The developed method was validated against and showed good agreement with an earlier reported dissolution-precipitation method.

  • 316.
    Hansson, Susanne
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    ARGET ATRP as a Tool for Cellulose Modification2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The importance of finding new applications for cellulose‐based products has increased, especially to meet the demand for new environmentally friendly materials, but also since the digitalization of our society will eventually decrease the need for paper. To expand the application area of cellulose, modification to improve and/or introduce new properties can be a requisite. Thus, the focus of this study has been to achieve fundamental knowledge about polymer grafting of cellulose via well‐controlled radical polymerization.

    Cellulose, in the form of filter paper, has successfully been grafted via activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of the monomers: methyl methacrylate, styrene, and glycidyl methacrylate. The advantages of ARGET ATRP are that only a small amount of a copper catalyst is required and the reaction can be performed in limited amount of air; yet, providing for relatively well‐controlled reactions. These benefits can render ARGET ATRP an attractive method for industrial utilization.

    The contact‐angle measurements of the grafted filter papers confirmed that the hydrophobicity of cellulose was significantly increased, even for shorter graft lengths. FT‐IR spectroscopy established that the amount of polymer successively increased with monomer conversion. High‐resolution FT‐IR microscopy (FT‐IRM) was proven to be a very useful technique for the analysis of cellulose substrates, displaying the spatial distribution of polymer content on cellulose fibers. The polymer was shown to be fairly homogenously distributed on the fiber.

    An initiator with a reducible disulfide bond rendered cleavage of the polymer grafts possible, employing mild reaction conditions. The cleaved grafts and the free polymers – formed from a sacrificial initiator in parallel to the grafting – were shown to have similar molar masses and dispersities, confirming that the grafts can be tailored by utilizing a sacrificial initiator. Moreover, the initiator content on filter paper and microcrystalline cellulose was assessed.

    A comparison between the two grafting techniques, grafting‐from cellulose via ARGET ATRP and grafting‐to cellulose via copper(I)‐catalyzed alkyne‐azide cycloaddition, was performed. To achieve a trustworthy comparison, the free polymer formed in parallel to the grafting‐from reaction was employed as the prepolymer in the grafting‐to approach, resulting in nearly identical graft length on the substrates for the two grafting methods. FT‐IRM analyses verified that under the selected conditions, the grafting‐from technique is superior to the grafting‐to approach with respect to controlling the distribution of the polymer content on the surface. The results were corroborated with X‐ray photoelectron spectroscopy.

  • 317.
    Hansson, Susanne
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Trouillet, Vanessa
    KIT Institute for Applied Materials (IAM-ESS).
    Tischer, Thomas
    KIT Institut für Technische Chemie und Polymerchemie.
    Goldmann, Anja
    KIT Institut für Technische Chemie und Polymerchemie.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Barner-Kowollik, Christopher
    KIT Institut für Technische Chemie und Polymerchemie.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Grafting Efficiency of Synthetic Polymers onto Biomaterials: A comparative study of grafting- from versus grafting- to2013Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 14, nr 1, s. 64-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, the two grafting techniques grafting-from - by activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) - and grafting-to - by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) - were systematically compared, employing cellulose as a substrate. In order to obtain a meaningful comparison, it is crucial that the graft lengths of the polymers that are grafted from and to the substrates are essentially identical. Herein, this was achieved by utilizing the free polymer formed in parallel to the grafting-from reaction as the polymer for the grafting-to reaction. Four graft lengths were investigated, and the molar masses of the four free polymers (21 ≤ Mn ≤ 100 kDa; 1.07 ≤ M ≤ 1.26), i.e. the polymers subsequently employed in the grafting-to reaction, were shown to be in the same range as the molar masses of the polymers grafted from the surface (23 ≤ Mn ≤ 87 kDa; 1.08 ≤ M ≤ 1.31). The molecular weights of the chains grafted from the surface were established after cleavage from the cellulose substrates via size exclusion chromatography (SEC). High-resolution Fourier transform infrared microscopy (FT-IRM) was employed as an efficient tool to study the spatial distribution of the polymer content on the grafted substrates. In addition, the functionalized substrates were analyzed by X-ray photoelectron spectroscopy (XPS), contact angle (CA) measurements, and field-emission scanning electron microscopy (FE-SEM). For cellulose substrates modified via the grafting-from approach, the content of polymer on the surfaces increased with increasing graft length, confirming the possibility to tailor not only the length of the polymer grafts but also the polymeric content on the surface. In comparison, for the grafting-to reaction, the grafted content could not be controlled by varying the length of the preformed polymer: the polymer content was essentially the same for the four graft lengths. Consequently, the obtained results, when employing cellulose as a substrate and under these conditions, suggest that the grafting-from approach is superior to the grafting-to technique with respect to controlling the distribution of the polymeric content on the surface.

  • 318.
    Hassanzadeh, Masoumeh
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Composition and Application Potentials of Scandinavian Tunicates2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Marine ecosystems can be a promising reservoir of various kinds of chemical components, applicable as pharmaceutical materials, food, cosmetics, nutraceuticals, and others for different industry. As an example, Tunicates, a group of marine animals, have been attracted a lot of attention in medical application, food market, water pollution issues, and Cellulose nanomaterial production due to their consisting of chemical compounds such as cellulose, amino-sugars, and proteins or protein-polysaccharide complexes e.g. collagen, glycosaminoglycan, chitin, scleroprotein, iodine-binding proteins, and elastin. In this project,  two dominant species of Scandinavian Tunicates, i.e. Ciona intestinalis and Clavelina lepadiformis, harvested from Norwegian ocean have been classified according to body sizes, depths from the ocean surface, ages and species, and separated physically into outer layer and internal organs, followed by measurements of sugar composition, oil content, and  protein content. Application potentials have been investigated by trials for production of pure crystalline cellulose, bioethanol, and biodiesel, and by analysis of amino acid composition of the samples.

    The cellulose percentage and cellulose yield for the chemically pure cellulose obtained, is around 96% and 54% respectively, and the protein content is decreased step by step by the acid, alkali, and bleaching process applied. Bioethanol can be obtained by fermentation of tunicate hydrolysate with strains A and C which are derived from Saccharomyces cerevisiae. The biodiesel yield of tunicate samples is around 4-6% as an average. The amino acid compositions in our tunicate samples are similar to egg albumin, implying tunicate being an alternative material for animal feed production.

    Several processing treatments have been conducted with the aims to fractionate tunicate biomass components or enhance the cellulose accessibility and reactivity. After a single processing step, Ba(OH)2 treated samples seemed to be the best in terms of both cellulose preservation (66.5% cellulose) and protein removal (6% protein in the treated residue). Results from the physical separation plus washing reveal that the highest amount of cellulose and protein presents is found in the outer (Tunic) part and internal organs of Tunicate samples respectively. Data obtained from FTIR(Fourier Transform Infrared Spectroscopy) and SEM(Scanning Electron Microscope) indicate that among all processing trials, H3PO4 is the most effective in decreasing the cellulose crystallinity, which renders a higher accessibility for acidic or enzymatic reaction during bioethanol production due to a higher amount of amorphous structure of cellulose.

    From the analysis results of component contents and structures, it could be concluded that increase of deepness results in a decrease of sugar content of the Tunicate samples while there are no differences in protein and carbohydrate content in different tunicate species. The body size has a positive influence on the protein content and the sample age alters the contents of both sugar and protein. In addition, Tunicate oil has high phospholipid content instead of glycerol ester, the latter being the common oil from vegetable origins. Moreover, lots of free fatty acid is present, and the composition profile of Tunicate fatty acids seems to be similar to fish oil, as revealed by NMR (Nuclear Magnetic Resonance Spectroscopy), FTIR, and GC-MS (Gas Chromatography-Mass Spectrometry).

  • 319.
    Hassanzadeh, Salman
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Adolfsson, Karin H.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Controlling the cooperative self-assembly of graphene oxide quantum dots in aqueous solutions2015Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, nr 71, s. 57425-57432Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fascinating 3D cooperative self-assembly behavior was observed for 2D graphene oxide quantum dots (GOQDs) in dilute and semi dilute aqueous solutions. In addition the optical properties could be tuned by controlling the supramolecular structures. While the electrostatic interactions between the charged single sheets were assigned as the main secondary interactions that were responsible for the supramolecular fine structures, the concentration, temperature, salt concentration and pH could tune the repulsive/attractive forces and the molecular binding between the GOQD sheets. The morphological studies combined with UV-Vis and fluorescence evaluations proved that after a slow nucleation step, elongation preceded radially by H-aggregate self-association of the GOQD monomers, forming the final porous spheres by radial growth of rods. The quenching properties of the self-associated-assembled GOQDs together with the excitation wavelengths of the GOQD solutions enabled tuning of the fluorescence intensity and color of the final solutions, which could be utilized for e.g. bioimaging and smart spectroscopy.

  • 320.
    Hassanzadeh, Salman
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Adolfsson, Karin H.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wu, Duo
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Supramolecular Assembly of Biobased Graphene Oxide Quantum Dots Controls the Morphology of and Induces Mineralization on Poly(epsilon-caprolactone) Films2016Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, nr 1, s. 256-261Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biobased 2D graphene oxide quantum dots (GOQDs) were synthesized from waste paper via carbon nanosphere intermediates and evaluated as property-enhancing additives for poly(epsilon-caprolactone) (PCL). The morphology of PCL films was controlled by supramolecular assembly of the small, 2D GOQDs in the polymer matrix. Phase behavior studies of PCL-GOQD in the solid state indicated concentration-dependent self-association of GOQD sheets, which was confirmed by SEM observations. Depending on the GOQD concentration, the formation of, e.g., spheres and stacked sheets was observed. GOQDs also induced mineralization on the surface of the films. A calcium phosphate (CaP) mineralization test revealed that the density of growing CaP crystals was controlled by the type of GOQD aggregates formed. Thus, utilization of the aggregation behavior of small GOQD sheets in polymeric matrices paves the way for tuning the morphology and properties of nanocomposites.

  • 321.
    Hassanzadeh, Salman
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Aminlashgari, Nina
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Microwave-Assisted Recycling of Waste Paper to Green Platform Chemicals and Carbon Nanospheres2015Inngår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 3, nr 1, s. 177-185Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Effective high-yield recycling of waste paper to well-defined future platform chemicals and carbon nanospheres was demonstrated. The developed process utilized the exceptional combined effect of microwave irradiation and dilute acid catalyst to hydrothermally degrade cellulose in waste paper. The process was evaluated for three different waste papers, brown and white paper tissues and white printing paper. Different pretreatment processes were investigated to further increase the cellulose liquefaction efficiency. By utilizing soda pretreatment, liquefaction efficiencies as high as 8896 were achieved. The obtained liquefaction products were fingerprinted by NMR and LDI-MS, while the solid residues were analyzed by XRD, SEM, TGA, and FTIR As industrial-scale microwave reactors are currently under development, the developed method displays significant potential for recycling waste paper to green platform chemicals at the industrial scale.

  • 322.
    Hatton, Fiona L.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Tailor-made copolymers for the adsorption to cellulosic surfaces2015Inngår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 65, nr SI, s. 325-339Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The utilization and modification of cellulose, in particular nanocelluloses, for applications in bioplastics and biocomposites has been well studied in recent years. There is an increasing need for materials with good mechanical properties from renewable resources to replace current polymeric materials derived from fossil fuels. The modification of cellulose is essential to improve compatibility with hydrophobic matrices. For this purpose, various modification techniques have been employed such as physical adsorption of polymers to cellulosic substrates. This review aims to summarize the existing literature describing the physical adsorption of tailor-made copolymers to cellulosic surfaces. This area of cellulose modification incorporates a broad range of polymeric materials, and the expansion of this method of cellulose modification is promising for future sustainable, renewable and 'green' material development.

  • 323. He, Min
    et al.
    Cui, Xiaofei
    Jiang, Huiyi
    Huang, Xuelian
    Zhao, Weifeng
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Zhao, Changsheng
    Super-Anticoagulant Heparin-Mimicking Hydrogel Thin Film Attached Substrate Surfaces to Improve Hemocompatibility2017Inngår i: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195, Vol. 17, nr 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, heparin-mimicking hydrogel thin films are covalently attached onto poly(ether sulfone) membrane surfaces to improve anticoagulant property. The hydrogel films display honeycomb-like porous structure with well controlled thickness and show long-term stability. After immobilizing the hydrogel films, the membranes show excellent anticoagulant property confirmed by the activated partial thromboplastin time values exceeding 600 s. Meanwhile, the thrombin time values increase from 20 to 61 s as the sodium allysulfonate proportions increase from 0 to 80 mol%. In vitro investigations of protein adsorption and blood-related complement activation also confirm that the membranes exhibit super-anticoagulant property. Furthermore, gentamycin sulfate is loaded into the hydrogel films, and the released drug shows significant inhibition toward E. coli bacteria. It is believed that the surface attached heparin-mimicking hydrogel thin films may show high potential for the applications in various biological fields, such as blood contacting materials and drug loading materials.

  • 324.
    He, Yunjuan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Boluk, Yaman
    Univ Alberta, Dept Civil & Environm Engn, Edmonton, AB, Canada..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, Stockholm, Sweden..
    Deltin, Tomas
    PTE Coatings AB, Gamleby, Sweden..
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Comparative study of CNC and CNF as additives in waterborne acrylate-based anti-corrosion coatings2019Inngår i: Journal of Dispersion Science and Technology, ISSN 0193-2691, E-ISSN 1532-2351Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocomposite coatings are of great interest as barrier coatings since synergy effects between matrix and additive properties can be achieved. This, however, requires favorable additive-matrix interactions to provide a strong interphase (interface region). In this work we elucidate the properties of two environmentally benign nanocomposite coatings based on a waterborne acrylate formulation with additives from renewable sources, i.e. either cellulose nanocrystals, CNC; or, alternatively, cellulose nanofibrils, CNF. We focus on the corrosion protective properties of these coatings and discuss the reason why the nanocomposite with CNC displays favorable corrosion protection properties whereas that with CNF does not. To this end we utilized scanning electron microscopy, water contact angle measurement, Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy techniques to investigate the microstructure, surface wetting, interactions between cellulosic materials and matrix as well as corrosion protective properties of both composite coatings.

  • 325.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Editorial2017Inngår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 57Artikkel i tidsskrift (Fagfellevurdert)
  • 326.
    Hedenqvist, Mikael S.
    et al.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Ritums, Janis
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Conde-Brana, M.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Bergman, Gunnar
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Structure and properties of poly(ethylene-co-chlorotrifluoroethylene) and polyvinylidene fluoride exposed to water, hydrochloric acid, hydrobromic acid and tetrachloroethylene2004Inngår i: Polymer Engineering and Science, ISSN 0032-3888, E-ISSN 1548-2634, Vol. 44, nr 1, s. 113-122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transport of water, hydrochloric acid. hydrobromic acid and tetrachloroethylene in poly(ethylene-co-chlorotrifluoroethylene) and polyvinylidene fluoride were studied at 70degreesC by the sorption/desorption technique. The effects on the structure and mechanical properties were studied using size-exclusion chromatography, infrared spectroscopy, differential scanning calorimetry and tensile testing. Solute concentrations in the polymers indicated that both the water and HCl/HBr components diffused into the polymers on exposure to acid solutions. The calculated water contents of the diffusing acids generally differed from the water content in the solution. The ratio of water content in the diffusing acid to that in the surrounding acid solution was generally a function of the relative vapor activity of water and HCl/HBr. It was possible to describe the 35% HCl and 47% HBr desorption data using a two-component model. It was assumed that the water and HCl/HBr diffused separately, each having its own constant diffusion coefficient. The water diffusivity was obtained from the pure water system, and this allowed the HCl/HBr diffusivity to be calculated. It was found that the diffusivity decreased, in a non-simple way, as a function of solute size. The exposure to solute did not lower the molar mass of the polyvinylidene fluoride. Differential scanning calorimetry indicated the development of low-melting point polyvinylidene fluoride crystals during the exposure to all solutes. This seemed to be a consequence of the long-term exposure (175 to 376 days) at 70degreesC. The long-term exposure stiffened several of the polyvinylidene fluoride resins and occasionally made them less ductile. The poly(ethylene-co-chlorotrifluoroethylene) also became stiffer, but it was otherwise unaffected as far as observation by the other available techniques was concerned.

  • 327.
    Helander, Mikaela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The Use of Membrane Filtration to Improve the Properties of Extracted Wood Components2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The forest is alarge and important natural resourcein Sweden, and approximately 70% of the country’s land area is woodland. Wood is an excellent raw material for the replacement of oil-based products because it is renewable, biodegradable and carbon neutral. Furthermore, the forest industry is searching for new processes and methods to utilise by-product streams in a so-called integrated biorefinery. A key to the success of producing new products from wood could be pure and homogenous raw materials. Because wood contains a large variety of components with different characteristics and sizes, cross-flow filtration (CFF) will be a key separation technique to obtain homogenous and pure raw materials in the biorefinery concept.

    Different wood material components have been studied in this thesis. The first part of this work focuses on kraft lignin. Kraft lignin is interesting because approximately 3.5-4 million metric tonnes are produced in Sweden annually (~7million tonnes of kraft pulp/year in 2012), and today it is mainly used as fuel. The second part of this thesis deals with materials in hot water extract (i.e.,  galactoglucomannan, but also other components). These extracted materials are interesting because similar materials are extracted in thermomechanical pulping process by-product streams. Finally, nanocellulose has been studied since it is an interesting raw material for future applications.

    Through CFF, kraft lignin from black liquor has been fractionated into raw material samples with more homogeneous characteristics such as molecular weight, aromatic hydroxyl groups and thermal properties. From dynamic mechanical analysis, low molecular weight fractions were found to have the highest degree softening. To precipitate low molecular weight fractions (<1000 Dacut-off) into a convenient solid, lower temperatures than forhigh molecular weight fractions were needed. To produce low molecular weight lignin (<5000 Da cut-off) from re-dissolved LignoBoost lignin, lower lignin concentrations and higher pH and ionic strength were found to increase the permeate fluxat the tested conditions.

    Nanocellulose has been producedby a novel process called nanopulping and has subsequently been size fractionated by CFF to obtain more homogenous nanocellulose.

    CFF and adsorption chromatography can be used to isolate dissolved wood components, yielding several upgraded products: lignin, lignin-carbohydrate complexes, and galactoglucomannan.

  • 328.
    Hellberg, J
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Remonen, T
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Johansson, M
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Inganas, O
    Theander, M
    Engman, L
    Eriksson, P
    New monomers for polythiophenes1997Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 84, s. 251-252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two series of chalcogen substituted thiophene monomers have been synthesised; 3-(4-alkylchalcogenophenyl)thiophenes 1a-c and 3-(4-alkylphenylchalcogeno)thiophenes 2a-d. Polymerisations of examples of these with iron(III)chloride gave regiorandom polymers. Light-emitting diodes with low efficiency could be fabricated from poly-1a and poly-1b.

  • 329. Hellberg, J
    et al.
    Remonen, T
    Johansson, Mats
    Inganas, O
    Theander, M
    Engman, L
    Eriksson, P
    New monomers for polythiophenes1997Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 84Artikkel i tidsskrift (Fagfellevurdert)
  • 330. Henrik Ullsten, N.
    et al.
    Gällstedt, M.
    Spencer, G. M.
    Johansson, E.
    Marttila, S.
    Ignell, R.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Extruded high quality materials from wheat gluten2010Inngår i: Polymers from Renewable Resources, ISSN 2041-2479, Vol. 1, nr 4, s. 173-186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, we report that the addition of ammonium hydroxide (NH4OH)significantly enhance the properties of extruded WG-based materials. The grainystructure disappeared and the extrudate became more uniform and glossy. Thebarrier properties improved and the oxygen permeability at dry conditions was aslow as that for a number of petroleum-based plastics (poly(ethylene terephthalateand polyamide 66). The protein structure in this material was extensivelyaggregated, which improved the strength and stiffness; there was a ca 4-foldincrease in maximum stress compared to that of the NH4OH-free samples. Theprotein solubility decreased to almost zero. Even a severe sonication treatmentin sodium dodecyl sulphate (SDS) did not increase the solubility. The only typeof protein that it was possible to extract was the 'thermo-resistant' w-gliadinslacking disulfide-bonds. Our result provides new opportunities to develop a WGbasedfilm extrudate for potential use as e.g. a renewable barrier layer in foodand non-food laminate packagings.

  • 331. Hermosilla, Viviana
    et al.
    Ibarra, David
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    On the accessibility and reactivity of different kraft pulps used for cellulose derivatives2007Konferansepaper (Fagfellevurdert)
  • 332. Hermosilla, Viviana
    et al.
    Nanko, Hiroushi
    Ek, Monica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Influence of Mechanical and Enzymatic Treatment on Cellulose Accessibility2007Konferansepaper (Fagfellevurdert)
  • 333.
    Heydari, Golrokh
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Stenroos, Christian
    Koivuluoto, Heli
    Tuominen, Mikko
    Claesson, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Ultralow ice adhesion on hydrophilic and molecularly smooth mica surfacesManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Despite much research on designing surfaces for combating icing, no permanent solution has been achievedusing solid materials. Inspired by the slippery surface of ice, attributed to the presence of a quasi-liquid layeracting as a natural lubricant, we hypothesize that flat hydrophilic surfaces with a hydration layer remaining inthe liquid-like state at the solid-ice interface could result in low ice adhesion. Utilizing temperature-controlledice adhesion measurements on the molecularly smooth basal plane of muscovite mica, we observed the lowestreported ice adhesion on solid surfaces down to temperatures of -35 ºC. The ice adhesion is dramatically higheron flat hydrophilic silica surfaces. We discuss these findings in terms of what is known about mica-water andmica-ice interactions.

  • 334.
    Heydari, Golrokh
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Visnevskij, Ceslav
    Makuska, Ricardas
    Claesson, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Temperature-Dependent Deicing Properties of ElectrostaticallyAnchored Branched Brush Layers of Poly(ethylene oxide)2016Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, nr 17, s. 4194-4202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hydration water of hydrophilic polymersfreezes at subzero temperatures. The adsorption of suchpolymers will result in a hydrophilic surface layer that stronglybinds water. Provided this interfacial hydration water remainsliquidlike at subzero temperatures, its presence could possiblyreduce ice adhesion, in particular, if the liquidlike layer isthicker than or comparable to the surface roughness. Toexplore this idea, a diblock copolymer, having one branchedbottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. Theshear ice adhesion strength on such polymer-coated surfaces was investigated down to −25 °C using a homebuilt device. Inaddition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branchedbottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, attemperatures above −15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer.Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of waterinteracting with branched and linear poly(ethylene oxide) (with hydration water melting points of about −18 and −10 °C,respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branchedbottle-brush structured poly(ethylene oxide) at −10 °C, whereas no significant adhesion reduction was obtained with linearpoly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottlebrushstructured poly(ethylene oxide), which, in the bulk, does not freeze until −18 °C.

  • 335. Hoang, A. T.
    et al.
    Pallon, Love
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Liu, Dongming
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Serdyuk, Y. V.
    Gubanski, S. M.
    Gedde, Ulf W.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Charge transport in LDPE nanocomposites part I-experimental approach2016Inngår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 8, nr 3, s. 1-19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents results of bulk conductivity and surface potential decay measurements on low-density polyethylene and its nanocomposites filled with uncoated MgO and Al2O3, with the aim to highlight the effect of the nanofillers on charge transport processes. Material samples at various filler contents, up to 9 wt %, were prepared in the form of thin films. The performed measurements show a significant impact of the nanofillers on reduction of material's direct current (dc) conductivity. The investigations thus focused on the nanocomposites having the lowest dc conductivity. Various mechanisms of charge generation and transport in solids, including space charge limited current, Poole-Frenkel effect and Schottky injection, were utilized for examining the experimental results. The mobilities of charge carriers were deduced from the measured surface potential decay characteristics and were found to be at least two times lower for the nanocomposites. The temperature dependencies of the mobilities were compared for different materials.

  • 336.
    Hollertz, Rebecca
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Cellulose-based electrical insulation materials: Dielectric and mechanical properties2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The reliability of the generation and distribution of electricity is highly dependent on electrical insulation and is essential for the prosperity of our society and a ubiquitous part of our everyday life. The present study shows how some important material properties affect the electrical properties of cellulose-based electrical insulation systems which are used together with mineral oil in high-voltage transformers. Among other things, the effects of paper density and of the lignin content of the fibres on the dielectric response and charge transport of the papers have been studied.

    The underlying mechanisms of the inception and propagation of streamers, responsible for the most costly failures in transformers, at the oil-solid interface have been investigated and the important role of paper morphology on streamer propagation has been demonstrated. It was also shown that for polymers with permittivities close to that of the oil, the inception voltage was higher than with polymers with higher permittivities.

    Fibres were also modified prior to paper sheet preparation in attempts to improve the mechanical and dielectric properties. The properties of papers containing cellulosic micro- and nanofibrils and SiO2 and ZnO nanoparticles indicate that these additives can indeed be used to improve both the mechanical and dielectric properties. For example, a three-layered structure with two papers laminated together with a thin layer of microfibrillated cellulose also showed an increased DC breakdown strength by 47 % compared to a single-layer paper with a similar thickness.

  • 337.
    Hollertz, Rebecca
    et al.
    EMPA, Switzerland .
    Chatterjee, S
    Gutmann, H
    Geiger, T
    Nüesch, F A
    Chu, B T T
    Improvement of toughness and electrical properties of epoxy composites with carbon nanotubes prepared by industrially relevant processes2011Inngår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 22, nr 12, s. 125702-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The addition of carbon nanotubes (CNTs) to polymeric matrices or master batches has the potential to provide composites with novel properties. However, composites with a uniform dispersion of CNTs have proved to be difficult to manufacture, especially at an industrial scale. This paper reports on processing methods that overcome problems related to the control and reproducibility of dispersions. By using a high pressure homogenizer and a three-roll calendaring mill in combination, CNT reinforced epoxies were fabricated by mould casting with a well dispersed nanofiller content from 0.1 to 2 wt%. The influence of the nano-carbon reinforcements on toughness and electrical properties of the CNT/epoxies was studied. A substantial increase of all mechanical properties already appeared at the lowest CNT content of 0.1 wt%, but further raising the nanofiller concentration only led to moderate further changes. The most significant enhancement was obtained for fracture toughness, reaching up to 82%. The low percolation thresholds were confirmed by electrical conductivity measurements on the same composites yielding a threshold value of only about 0.01 wt%. As corroborated by a thorough microscopic analysis of the composites, mechanical and electrical enhancement points to the formation of an interconnected network of agglomerated CNTs.

  • 338.
    Holmqvist, Jonna
    KTH, Skolan för kemivetenskap (CHE).
    Hemicellulose-Based Wood Adhesives2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The interest in producing alternatives to petroleum-based wood adhesives is due to the growing consciousness of fossil fuels’ impact on the environment. Also, the paper industry needs to adapt to a market where paper is replaced by technology, and develop new materials and functions from wood. A wood adhesive is a material that chemically and/or physically binds two wood surfaces together. Today most  adhesives are petroleum-based and the main application, volume-wise, is manufacturing building materials, such as plywood.

    Hemicellulose is a group of polysaccharides that reside within the cell wall of terrestrial plants. Hemicellulose is the second most abundant polysaccharide family in nature, after cellulose, and it is a hydrophilic component that contributes to the plant cell wall’s flexibility by linking together cellulose and lignin. Galactoglucomannan is the most common hemicellulose in softwood, while xylan is the most common hemicellulose in hardwood.

    In this study, hemicellulose has been used as a binder in adhesive mixtures. The hemicellulose was extracted using a pilot-scale model for pre-hydrolysis and sulfate cooking of hardwood and softwood wood chips at Holmen AB, to simulate the industrial process. Parameters that were evaluated were conditioning time (24 h and 7 days), different dispersing agents (PVAm, PEI and chitosan), different solid content  of hemicellulose (20, 30, 40, and 50 wt%), different pH of dispersing agents, different strain rates (1 mm/min and 50 mm/min). A comparison between applying mixed components and applying the components separately has also been performed.

    The results showed that 20 and 30 wt% solid content in the adhesive gave the best result, PVAm directly from the bottle performed best as a dispersing agent and there was no significant difference between conditioning the samples 24 h and 7 days. Furthermore, mixing the components before application showed better results, and there was no large difference between 1 mm/min and 50 mm/min strain rate.

    The samples have been characterized using Fourier transform infrared spectroscopy (FTIR), and evaluated using Instron 5566 to determine the critical separation stress. The extracted hemicellulose was sent to MoRe Research for carbohydrate and molecular weight analyses.

  • 339.
    Hua, Geng
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    From Food Additive to High-Performance Heavy Metal Adsorbent: A Versatile and Well-Tuned Design2016Inngår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A biosourced, cross-linked hydrogel-type heavy metal adsorbent is presented. Various factors such as the highly efficient chemical interactions, the various network structures, the decreased energy consumption during cross-linking, and the negligible amount of generated waste are considered when designing the adsorbent. The widely applied, naturally occurring food additive δ-gluconolactone is studied as a building block for the adsorbent. Aminolysis reactions were applied to form linear dimer precursors between diamines and δ-gluconolactones. The abundant hydroxyl groups on the dimers from δ-gluconolactone were fully exploited by using them as the cross-linking sites for reactions with ethylenediaminetetraacetic dianhydride, a well-known metal-chelating moiety. The versatility of the adsorbent and its metal-ion binding capacity is well tuned using dimers with different structures and by controlling the feed ratios of the precursors. Buffers with different pH values were used as the conditioning media to examine the swelling properties and the mechanical properties of the hydrogels, revealing that both properties can be controlled. High heavy metal chelating performance of the adsorbent was determined by isothermal adsorption kinetics, titration, and thermal gravimetric analysis. The adsorbent exhibits an outstanding chelating ability toward the three tested heavy metals (Cu(II), Co(II), Ni(II)), and the maximum adsorption capacity (qm ∼ 121 mg·g–1) is higher than that of the majority of the reported biosourced adsorbents.

  • 340.
    Huang, Tianxiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Li, Dongfang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Water repellency improvement of cellulosic textile fibers by betulin and a betulin-based copolymer2018Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 3, s. 2115-2128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Betulin is a naturally abundant and hydrophobic compound in the outer bark of birch and can readily be obtained by solvent extraction. Here, solutions of betulin were used to treat cotton fabrics and improve their water repellency. Cotton fabric impregnated in a solution of betulin in ethanol showed a contact angle for water of approximately 153A degrees and reached a water repellency score of 70 according to a standard water repellency test method. A betulin-terephthaloyl chloride (TPC) copolymer was synthesized. Both betulin and betulin-TPC copolymer were characterized by nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The copolymer was characterized by size exclusion chromatography and differential scanning calorimetry. When impregnated with a solution of betulin-TPC copolymer in tetrahydrofuran, a cotton fabric showed a water contact angle of 151A degrees and also reached a water repellency score of 70. Films based on betulin and betulin-TPC copolymer were prepared and coated onto the surface of the fabrics by compression molding. These coated fabrics showed water contact angles of 123A degrees and 104A degrees respectively and each reached a water repellency score of 80.

  • 341. Hufendiek, Andrea
    et al.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Meier, Michael A. R.
    Barner-Kowollik, Christopher
    Fluorescent Covalently Cross-Linked Cellulose Networks via Light Induced Ligation2016Inngår i: ACS Macro Letters, E-ISSN 2161-1653, Vol. 5, nr 1, s. 139-143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A facile light-induced procedure for the covalent cross-linking of cellulose at ambient conditions employing the nitrile imine mediated tetrazole-ene cycloaddition (NITEC) reaction is presented. Cellulose-tetrazoles with 2 degrees of substitution (0.14 and 0.23) were synthesized in a solution based transesterification procedure in an ionic liquid. Two bismaleimides with either a trioxatridecane or a dithiodipropionyl backbone were used as cross-linkers to form fluorescent, covalently cross-linked cellulose networks and films, which were characterized by UV/vis spectroscopy, fluorescence spectroscopy, DSC, and TGA. The films showed a broad emission band from 500-700 nm and were thermally stable up to 200 degrees C. Using the bismaleimide with a disulfide moiety as the cross-linker, reductive degradation of the films can be induced. Finally, cellulose-tetrazole was cross-linked in a spatially resolved fashion, providing a strategy for the shaping of films based on renewable resources.

  • 342.
    Hui, Sun
    et al.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Wirsen, Anders
    KTH, Tidigare Institutioner, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner, Polymerteknologi.
    Electron beam-induced graft polymerization of acrylic acid and immobilization of arginine-glycine-aspartic acid-containing peptide onto nanopatterned polycaprolactone2004Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 5, nr 6, s. 2275-2280Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electron beam- (EB-) induced graft polymerization of acrylic acid and the subsequent immobilization of arginine-glycine-aspartic acid (RGD) peptide onto nanopatterned polycaprolactone with parallel grooves is reported. A high concentration of carboxylic groups was introduced onto the polymer substrate by EB-induced polymerization of acrylic acid. In the coupling of the RGD peptide to the carboxylated polymer surface a three-step peptide immobilization process was used. This process included the activation of surface carboxylic acid into an active ester intermediate by use of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), the introduction of disulfide groups by use of 2-(2-pyridinyldithio)ethanamine tie hydrochloride (PDEA), and final immobilization of the peptide via a thioldisulfide exchange reaction. The extent of coupling was measured by UV spectroscopy. A preliminary study of the in vitro behavior of keratinocytes (NCTC 2544) cultured on the acrylic acid-grafted and RGD peptide-coupled surface showed that most cells grown on the coupled samples had a spread-rounded appearance, while the majority of cells tended to be elongated along the grooves on uncoupled substrates.

  • 343.
    HULT, A
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    JOHANSSON, M
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    MALMSTROM, E
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    DENDRITIC RESINS FOR COATING APPLICATIONS1995Inngår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 98, s. 1159-1161Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hyperbranched, aliphatic polyesters of theoretically calculated molar masses 1 200-44 300 (2-7 generations) were synthesized in the molten state from 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) (repeating unit of AB(x)-type) and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol (TMP) (core molecule) using acid catalysis. The synthetic procedure was a pseudo-one-step divergent reaction. The degree of branching was found to be near 80 %. A study has also been made with respect to the theological properties of the hyperbranched aliphatic polyesters. The polymers exhibit an almost newtonian behaviour in the molten state. They also exhibit a lower increase in viscosity with molecular weight than linear polymers. The surface functionality is shown to greatly affect the viscosity of the polymers.

  • 344.
    Hult, A
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Johansson, M
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Malmstrom, E
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Hyperbranched polymers1999Inngår i: BRANCHED POLYMERS II, SPRINGER-VERLAG BERLIN , 1999, Vol. 143, s. 1-34Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Polymers obtained from the statistical polymerization of A(x)B monomers by means of condensation or addition procedures are referred to as hyperbranched polymers. The paper aims to give a brief historical background and to give a survey of hyperbranched polymers in the literature. Polymerization of A(x)B monomers yields highly branched polymers, with a multitude of end groups, which are less prone than linear polymers to form entanglements and undergo crystallization. Hyperbranched polymers are phenomenologically different from linear polymers; for example, the lack of entanglements results in lower viscosity than in linear polymers of the same molecular weight. The thermal properties of hyperbranched polymers have been shown to depend on the nature of the chain ends. The lower the polarity, the lower the glass transition temperature since it is suggested that the glass transition of hyperbranched polymers is due to translational motions. Hyperbranched polymers are unique in that their properties ape easily tailored by changing the nature of the end groups. For some areas, such as coating resins and tougheners in epoxy-resins, hyperbranched polymers are foreseen to play an important role. Various applications have been suggested, even though only a few have been commercialized at this time.

  • 345. Hult, Anders
    et al.
    Johansson, Mats
    Malmström, Eva
    DENDRITIC RESINS FOR COATING APPLICATIONS1995Inngår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 98Artikkel i tidsskrift (Fagfellevurdert)
  • 346. Hult, Anders
    et al.
    Johansson, Mats
    Malmström, Eva
    Hyperbranched polymers1999Inngår i: Branched Polymers II, Springer-Verlag New York, 1999, Vol. 143, s. 1-34Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 347.
    Hult, Anders
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Malkoch, Michael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Antoni, Per
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Dendrimers with interior and exterior functionalities comprising of azide or alkyne groups for post- functionalization by huisgen click cycloaddition2008Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Novelty: A dendritic polymer comprising a core and repeating units, is new. Every repeating unit is bound to other unit(s) with bond(s) consisting of an ester, amide, thioether, ether, urethane, amine or imine.Use: The dendritic polymer is used for drug delivery systems, tissue engineering, data storage devices, markers for imaging, diagnostics, vaccines, phototherapeutics, optical devices, semiconductor, bioactive hydrogels and/or catalysts; for manufacture of a particle and a hydrogel (claimed); and for coatings, polyfunctional initiators for controlled radical polymerization or living free-radical polymerization techniques, ring-opening metathesis polymerization and ring-opening polymerization, dental and other composite materials, additives to control viscosity, rheology, solubility and stabilizing capacity, hybrid organic-inorganic materials, water-soluble materials, amphiphilic architectures, well-defined building blocks for precise architectural control, deposition of dendrimers on solid surfaces, dispersing agents for nanoparticles, dendrimer vehicles for encapsulation and/or delivery, and dendrimer scaffolds. The particle is used in encapsulation of low molecular compounds such as potent drugs, chelating species and fluorescent dyes.Advantage: The dendritic polymer can be functionalized both in the interior and in the exterior. It is possible to use a one-pot growth of dendritic polymer. There is provided the possibility to have more functional groups in a dendritic polymer compared to conventional polymer. When comparing the number of functional groups of a dendrimer based on A'B' x C' y -monomers with a traditional dendrimer based A'B' x -monomers, it is evident that the intrinsic functionality provides a larger number of available functional groups for post-modification. There is provided the possibility of a synthesis which is very robust, can be performed in various solvents, performed at both ambient and elevated temperatures, performed at atmospheric pressure as well as elevated, performed in a variety of gases including oxygen, nitrogen or argon. The synthesis has a high yield making the manufacture economical. There is the possibility to exclude an activation step prior to post-functionalization of a dendritic polymer. There is provided the possibility to add different types of functional groups simultaneously both to inner layer and/or to the outer layer.

  • 348. Hult, Anders
    et al.
    Malmström, Eva
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Johansson, Mats
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Sörensen, Kent
    Dendritic macromolecule, process for preparation thereof and use thereof1992Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention relates to a dendritic macromolecule of the polyester type comprising a central initiator molecule or initiator polymer having one or more reactive hydroxyl groups (A). The groups (A) are under formation of an initial tree structure bonded to reactive carboxyl groups (B) of a monomeric chain extender having the two reactive groups (A) and (B). The tree structure is optionally extended and further branched from the initiator molecule or initiator polymer by addition of further molecules of a monomeric chain extender by means of bonding between the reactive groups (A) and (B) thereof and is thereafter optionally further extended by reaction with a chain stopper. The invention also comprises a process for preparation of the dendritic macromolecule.

  • 349.
    Hult, Daniel
    KTH, Skolan för kemivetenskap (CHE).
    Influence of stereo regularity on mechanical and thermal properties of poly(lactic acid)2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The influence of stereo regularity in poly(lactic acid) (PLA) have been investigated, using poly(L-lactic acid) (PLLA) and poly(D,L-lactic acid) (PDLLA) with 4% D-lactide, to determine fatigue resistance. Samples were strain crystallized above Tg and studied with differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile testing. Both polymers exhibit heterogeneous characteristics in the amorphous phase observed by DSC and DMA, comprised according to the three phase model; of a mobile amorphous fraction (MAR, XMA), a rigid amorphous fraction (RAF, XRA) and a crystalline fraction (Xc). The effect of L/D ratio on crystallization kinetics and specific MAF was characterized with DSC. Its implications on mechanical properties after hydrated thermal conditioning, was observed on tensile stress-strain curves and alterations in glass transition dynamics with DMA. Enthalpy relaxation and fictive temperature was also studied with DSC to correlate structural relaxation with mechanical properties over time.

  • 350.
    Höglund, Anders
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Degradation profile of poly(epsilon-caprolactone) - the influence of macroscopic and macromolecular biomaterial design2007Inngår i: Journal of macromolecular science. Pure and applied chemistry (Print), ISSN 1060-1325, E-ISSN 1520-5738, Vol. 44, nr 7-9, s. 1041-1046Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Macroscopic and macromolecular material design and their influence on hydrolysis mechanism of poly(epsilon-caprolactone) (PCL) was evaluated. Homogoenous discs of linear PCL, porous scaffolds of linear PCL and crosslinked PCL networks were subjected to hydrolytic degradation for up to 364 days in 37 degrees C and pH 7.4 phosphate buffer solution. After different hydrolysis times, mass loss and changes in molecular weight and thermal properties were determined in parallel to extraction and analysis of the formed degradation products. Size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and gas chromatography-mass spectrometry (GC-MS) were used for the analyses. The results clearly demonstrated different degradation profiles and susceptibilities towards hydrolysis depending on the macroscopic and macromolecular biomaterial design.

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