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  • 1. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Degradation of enhanced environmentally degradable polyethylene in biological aqueous media: mechanisms during the first stages1994Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 51, nr 6, s. 1097-1105Artikkel i tidsskrift (Fagfellevurdert)
  • 2.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    The three stages in the degradation of polymers- polyethylene as a model substance1988Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 35, s. 1289-1302Artikkel i tidsskrift (Fagfellevurdert)
  • 3. Albertsson, Ann-Christine
    et al.
    Renstad, Rasmus
    Erlandsson, Bengt
    Eldsäter, Carina
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Effect of processing additives on (bio)degradability of film-blown poly(ε-caprolactone)1998Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 70, nr 1, s. 61-74Artikkel i tidsskrift (Fagfellevurdert)
  • 4.
    Alin, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Type of Polypropylene Material Significantly Influences the Migration of Antioxidants from Polymer Packaging to Food Simulants During Microwave Heating2010Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 118, nr 2, s. 1084-1093Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three different polypropylene materials, polypropylene homopolymer (PP), propylene-ethylene random copolymer (PP-R), and propylene-ethylene copolymer (PP-C) are commonly used in plastic containers designed for microwave heating of food. Migration of antioxidants, Irganox 1010 and Irgafos 168, from PP. PP-R, and PP-C during microwave heating in contact with different food simulants was investigated by utilizing microwave assisted extraction (MAE) and high performance liquid chromatography (HPLC). The polypropylene material significantly influenced the migration rate, which decreased in the order of increasing degree of crystallinity in the materials. PP homopolymer was the most migration resistant of the studied materials especially in contact with fatty food simulants. The use of isooctane as fatty food simulant resulted in rapid depletion of antioxidants, while migration to another fatty food simulant, 96% ethanol, was much more limited. Migration to aqueous and acidic food simulants was in most cases under the detection limits irrespective of microwaving time and temperature. The diffusion coefficients were similar to what have been found previously under similar conditions but without microwaves. The effect of swelling was shown by the large increase in the calculated diffusion coefficients when isooctane was used as food simulant instead of 96% ethanol. (C) 2010 Wiley Periodicals, Inc. I Appl Polym Sci 118: 1084-1093,2010

  • 5.
    Arias, Veluska
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Höglund, Anders
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Polylactides with "green" plasticizers: Influence of isomer composition2013Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 130, nr 4, s. 2962-2970Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Synthesized polylactides (PLA) with different D-isomer contents in the polymer chain were melt-blended with a series of green plasticizers by extrusion. Mechanical and thermal properties as well as the morphology of the plasticized materials were characterized to demonstrate how the combination of PLA with different D-contents and plasticizer controls the material properties. After addition of acetyl tributyl citrate (ATC), the elongation at break for PLA with a low D-isomer content was twice as high as that for PLAs with high D-isomer contents. Similar variations in the plasticization effect on the PLAs were also observed with the other plasticizers used, glyceryl triacetate (GTA), glycerol trihexanoate (GTH) and polyethylene glycol (PEG). In order to continue with the development of renewable polymers in packaging applications, the interrelation between a plasticizer and a specific polymer needs to be understood.

  • 6. Berthold, F
    et al.
    Gustafsson, K
    Berggren, R
    Sjoholm, E
    Lindström, Mikael
    Swed. Pulp/Paper Research Institute.
    Dissolution of softwood kraft pulps by direct derivatization in lithium chloride/N,N-dimethylacetamide2004Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 94, nr 2, s. 424-431Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method for the characterization of the molar mass distributions (MMDs) of softwood kraft pulps dissolved in 0.5% lithium chloride (LiCl)/N,N-dimethylacetamide (DMAc) by size exclusion chromatography is presented. The method is based on derivatization with ethyl isocyanate and the dissolution of samples in 8% LiCl/DMAc. In this study, the derivatization of hardwood kraft pulps did not influence the MMD. In the case of softwood pulps, however, the derivatization decreased the proportion of the high-molecular-mass material and increased the proportion of the low-molecular-mass material, which resulted in a distribution similar to the MMD of a hardwood kraft pulp. The results suggest that associations between hemicellulose and cellulose in the softwood kraft pulp were ruptured during derivatization. This led to a more correct estimation of the MMD of derivatized softwood kraft pulps than obtained by the dissolution of nonderivatized samples. This new method offers several advantages over derivatization with phenyl isocyanate: a precipitation step is not necessary, it is possible to follow the lignin distribution in the samples, and the method allows very high levels of dissolution of softwood kraft pulps up to a kappa number of around 50.

  • 7.
    Bruce, Carl
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Nilsson, Camilla
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Fogelström, Linda
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Paper-sheet biocomposites based on wood pulp grafted with poly(epsilon-caprolactone)2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 23, artikkel-id 42039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Kraft pulp fibers were used as substrates for the grafting of poly(epsilon-caprolactone) (PCL) from available hydroxyl groups through ring-opening polymerization, targeting three different chain lengths (degree of polymerization): 120, 240, and 480. In a paper-making process, paper-sheet biocomposites composed of grafted fibers and neat pulp fibers were prepared. The paper sheets possessed both the appearance and the tactility of ordinary paper sheets. Additionally, the sheets were homogenous, suggesting that PCL-grafted fibers and neat fibers were compatible, as demonstrated by both Fourier transform infrared spectroscopy microscopy and through dye-labeling of the PCL-grafted fibers. Finally, it was shown that the paper-sheet biocomposites could be hot-pressed into laminate structures without the addition of any matrix polymer; the adhesive joint produced could even be stronger than the papers themselves. This apparent and sufficient adhesion between the layers was thought to be due to chain entanglements and/or co-crystallization of adjacent grafted PCL chains within the different paper sheets. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42039.

  • 8. Camacho, W.
    et al.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Simultaneous determination of molecular weight and crystallinity of recycled HDPE by infrared spectroscopy and multivariate calibration2002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 85, nr 2, s. 321-327Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An attempt of correlating molecular weight (M,) of recycled high-density polyethylene (HDPE) as measured by size-exclusion chromatography (SEC) with diffuse reflectance near and mid-infrared spectroscopy (NIR/MIR) was made by means of multivariate calibration. The spectral data obtained was also used to extract information about the degree of crystallinity of the recycled resin. Differential scanning calorimetry (DSC) was used as the reference method. Partial leastsquares (PLS) calibration was performed on the MIR and NIR spectral data for prediction of Af, Four PC factors described fully the PLS models. The root-meansquare error of prediction (RMSEP) obtained with MIR data was 360, whereas a RMSEP of 470 was achieved when calibration was carried out on the diffuse reflectance NIR data. A PLS calibration for prediction of degree of crystallinity was performed on the NIR data in the 1100-1900-nm region, but the ability of prediction of this model was poor. However a PLS calibration in the region 2000-2500 nm yield better results. Four PC factors explained the most of the variance in the spectra and the RMSEP was 0.4 wt %.

  • 9. Camacho, W.
    et al.
    Valles-Lluch, A.
    Ribes-Greus, A.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Determination of moisture content in nylon 6,6 by near-infrared spectroscopy and chemometrics2003Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 87, nr 13, s. 2165-2170Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of moisture on the morphology and mechanical properties of polyamides have been extensively studied by a number of researchers. However, the assessment of water content in the resins has been carried out by thermal or thermogravimetric methods, which are destructive. In the present work partial least-squares (PLS) calibration models based on near-infrared (NIR) spectroscopy were produced in order to predict the moisture content of nylon 6,6. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and the loss-on-drying (LOD) method were used as reference methods. TGA, LOD, DSC, and NIR analysis were performed in parallel, and the obtained data were used for multivariate calibration purposes. Data pretreatment techniques such as derivation and multiplicative scattering correction (MSC) successfully eliminated the baseline offset present in the raw spectra and compensated for differences in thickness and light scattering of the analyzed samples. Calibration models were validated by full cross validation with the help of a test set. A comparison of the prediction ability of PLS models based on pretreated data was also done. NIR spectroscopy is a rapid and nondestructive method for the determination of moisture in recycled nylon. The moisture content can be predicted with a RMSEP = 0.05 wt %.

  • 10. Camacho, Walker
    et al.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Simultaneous determination of molecular weight and crystallinity of recycled HDPE by infrared spectroscopy and multivariate calibration2002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 85, nr 2, s. 321-327Artikkel i tidsskrift (Fagfellevurdert)
  • 11. Cardoso, Marcos R.
    et al.
    Martins, Renato J.
    Dev, Apurba
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF.
    Voss, Tobias
    Mendonca, Cleber R.
    Highly hydrophobic hierarchical nanomicro roughness polymer surface created by stamping and laser micromachining2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 24, artikkel-id 42082Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article describes the design and fabrication of hierarchical nanomicrostructured polymer surfaces with high hydrophobicity. The nanoscale roughness is achieved by stamping a ZnO nanowire film into PDMS. Subsequently, microstructures with different periodicities are created in the stamped PDMS sample by direct laser writing using femtosecond pulses. With this approach, we were able to produce hierarchical surface morphologies, composed of nano and microscale structures that exhibit water contact angles larger than 160 degrees.

  • 12.
    Cho, Sung-Woo
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Gällstedt, Mikael
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymera material.
    Effects of glycerol content and film thickness on the properties of vital wheat gluten films cast at pH 4 and 12010Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 117, nr 6, s. 3506-3514Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study deals with the optical properties and plasticizer migration properties of vital wheat gluten (WG) films cast at pH 4 and 11. The films contained initially 8, 16, and 25 wt % glycerol and were aged at 23 degrees C and 50% relative humidity for at least 17 weeks on a paper support to simulate a situation where a paper packaging is laminated with an oxygen barrier film of WG. The films, having target thicknesses of 50 and 250 mu m, were characterized visually and with ultraviolet/visible and infrared spectroscopy; the mass loss was measured by gravimetry or by a glycerol-specific gas chromatography method. The thin films produced at pH 4 were, in general, more heterogeneous than those produced at pH 11. The thin pH 4 films consisted of transparent regions surrounding beige glycerol-rich regions, the former probably rich in gliadin and the latter rich in glutenin. This, together with less Maillard browning, meant that the thin pH 4 films, in contrast to the more homogeneous (beige) thin pH 11 films, showed good contact clarity. The variations in glycerol content did not significantly change the optical properties of the films. All the films showed a significant loss of glycerol to the paper support but, after almost 9 months, the thick pH 11 film containing initially 25 wt % glycerol was still very flexible and, despite a better contact to the paper, had a higher residual glycerol content than the pH 4 film, which was also more brittle.

  • 13. Contat-Rodrigo, L.
    et al.
    Haider, N.
    Ribes-Greus, A.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Ultrasonication and microwave assisted extraction of degradation products from degradable polyolefin blends aged in soil2001Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 79, nr 6, s. 1101-1112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two nonconventional extraction techniques, microwave assisted extraction (MAE) and ultrasonication, were used to extract degradation products from polyolefins with enhanced degradability. High-density polyethylene/polypropylene blends with two different biodegradable additives (a granular starch/iron oxide mixture and Mater-Bi AF05H) were subjected to outdoor soil burial tests and removed at different periods of time between 0 and 21 months. The extracted products were analyzed by gas chromatography mass spectrometry (GC-MS). Ultrasonication was found to be a more suitable technique than MAE because of better reproducibility. In addition, higher amounts of certain products (e.g., carboxylic acids) were extracted by ultrasonication than by MAE. The degradation products extracted from the two blends were basically a homologous series of alkanes, alkenes, carboxylic acids, and alcohols. The amount of hydrocarbons (saturated and unsaturated) and alcohols remained basically the same as the degradation times increased. However, carboxylic acids tended to decrease slightly with the exposure time. Their concentration remained practically unchanged until 12 months of soil burial when a more significant decrease was noted. The quantitative analysis of the degradation products revealed for both samples a decrease in the amount of carboxylic acids with the exposure time, although the trend was different according to the additive used in each sample. For blends with Mater-Bi the amount of carboxylic acids was at a minimum after 12-month exposure in soil, which coincided with a minimum in the molecular weight distribution. After blends with granular starch/iron oxide were exposed to 3 months in soil, tetradecanoic acid was no longer detectable and the amount of hexadecanoic and octadecanoic acids decreased significantly. Solid-phase microextraction, a solvent-free extraction technique, was used to extract the degradation products that could have migrated to the soil from blends with Mater-Bi. Small amounts of tetradecanoic acid and dodecanol were identified by GC-MS in the soil surrounding the sample. The degradation patterns observed here correlate with our previous results from mechanical and morphological characterization of these samples.

  • 14.
    Edlund, Ulrica
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Copolymerization and polymer blending of trimethylene carbonate and adipic anhydride for tailored drug delivery1999Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 72, nr 2, s. 227-239Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The copolymerization in bulk and solution of trimethylene carbonate (TMC) with adipic anhydride (AA) as well as the blending of homopolymers are described. We show experimentally that the components are not copolymerizable but partially miscible, forming a microscopic dispersion without any visible signs of phase separation. Poly(adipic anhydride) (PAA) functions as a plasticizer, permitting an increase in the erosion rate by increasing the porosity and hydration. Drug delivery from the blends was evaluated. A statistical factorial model was designed to explore the influence of three important blend parameters and their interactions, making it possible to predict the erosion and drug-release behavior of the blend matrices. The PAA:poly(trimethylene carbonate) (PTMC) ratio and molecular weight of the polycarbonate component significantly influence the drug-release performance, mass loss, and degree of plasticization. The interaction among these factors also influences the blend properties. Plasticization of PTMC enhances the drug release to an extent that is dependent on the amount of PAA used. We demonstrate that blending offers a convenient alternative to copolymerization for the preparation of polymer matrices with predictable drug delivery.

  • 15.
    Espert, Ana
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Camacho, Walker
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Thermal and thermomechanical properties of biocomposites made from modified recycled cellulose and recycled polypropylene2003Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 89, nr 9, s. 2353-2360Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Residual cellulose fibers from the paper industry have been used as reinforcements in recycled polypropylene (PP) composites. The main obstacle to obtaining good properties with this biocomposite is deficiencies in the compatibility between the nonpolar matrices and the polar cellulose fibers used as reinforcements. The aim of this work was to improve the compatibilization between these cellulose fibers and the PP matrix with four different methods: modification by the addition of polypropylene-maleic anhydride copolymer (PPgMA) during the process of blending, preblending modification of the cellulose with a solution of PPgMA, modification of cellulose by silanes (vinyltrimethoxysilane), and acetylation of cellulose. Blends with all of the differently modified celluloses were prepared with the cellulose content varied up to 40%, and then all of the blends were subjected to thermal (differential scanning calorimetry and thermogravimetric analysis) and thermomechanical (dynamic mechanical thermal analysis) analyses. The results showed that the addition of cellulose fibers improved the thermomechanical behavior of the PP, increasing the value of the log of the dynamic modulus, and affected the thermal and thermooxidative behavior. Moreover, an advantage of the use of a recycled PP containing a small quantity of ethyl vinyl acetate (EVA) as a prime material in the composition was the enhancement of mechanical properties. The use of these methods for the modification of cellulose led to more desirable thermal and thermooxidative stabilities.

  • 16.
    Ezekiel Mushi, Ngesa
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer.
    Butchosa, Núria
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer.
    Zhou, Qi
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Nanopaper membranes from chitin-protein composite nanofibers: Structure and mechanical properties2014Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, nr 7, s. 40121-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chitin nanofibers may be of interest as a component for nanocomposites. Composite nanofibers are therefore isolated from crab shells in order to characterize structure and analyze property potential. The mechanical properties of the porous nanopaper structures are much superior to regenerated chitin membranes. The nanofiber filtration-processing route is much more environmentally friendly than for regenerated chitin. Minerals and extractives are removed using HCl and ethanol, respectively, followed by mild NaOH treatment and mechanical homogenization to maintain chitin-protein structure in the nanofibers produced. Atomic force microscope (AFM) and scanning transmission electron microscope (STEM) reveal the structure of chitin-protein composite nanofibers. The presence of protein is confirmed by colorimetric method. Porous nanopaper membranes are prepared by simple filtration in such a way that different nanofiber volume fractions are obtained: 43%, 52%, 68%, and 78%. Moisture sorption isotherms, structural properties, and mechanical properties of membranes are measured and analyzed. The current material is environmentally friendly, the techniques employed for both individualization and membrane preparation are simple and green, and the results are of interest for development of nanomaterials and biocomposites.

  • 17.
    Fateh-Alavi, Kamyar
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Gedde, Ulf W.
    KTH, Tidigare Institutioner, Polymerteknologi.
    A rapid microwave-assisted solvent extraction method for assessment of stabilizer concentration in crosslinked polydimethylsiloxane2004Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 93, nr 5, s. 2185-2192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Crosslinked polyclimethylsiloxanes were prepared containing 0.05 to 0.2 wt % of either a phenolic antioxidant (Irganox(R) 1010) or a hindered amine stabilizer (Tinuvin(R) 144). The stabilizer concentration was assessed by HPLC and UV-Vis spectroscopy of Soxhlet and microwave-assisted solvent extracts. Almost complete recovery of stabilizer was achieved with Soxhlet extraction. High stabilizer recovery was achieved when acetone was used as the solvent in the microwave-assisted extraction. HPLC was shown to be an efficient method for determining the concentration of Irganox 1010. For Tinuvin 144 the selectivity of both UV-Vis spectroscopy and HPLC was poor, leading to imprecise evaluation of the antioxidant concentration. The loss of stabilizer by migration from polymer to hot water (75 and 95degreesC) was monitored for the systems stabilized with Irganox 1010 and the diffusion coefficient of the antioxidant in the polymer was determined.

  • 18. Ferrari, Elena
    et al.
    Ranucci, Elisabetta
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Design of renewable poly(amidoamine)/hemicellulose hydrogels for heavy metal adsorption2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 12, s. 41695-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Renewable poly(amidoamine)/hemicellulose hydrogels were prepared from O-acetylated galactoglucomannan (AcGGM)-rich biomass and shown to display a significantly high adsorption capacity for Cu2+, Cd2+, Pb-2+,Pb- Zn2+, Ni2+, Co2+, and . Two different acrylamido end-capped poly(amidoamine) oligomers (PAA) were prepared and covalently immobilized onto an in situ formed polysaccharide network via water-based free radical graft copolymerization and cross-linking. The synthetic approach was shown to be viable when using a highly purified AcGGM or a crude spruce hydrolysate, an AcGGM and lignin containing biomass fraction as a reactant. Homogeneous reaction mixtures were obtained in both cases with polysaccharide contents up to 20% by weight. Oscillatory shear measurements indicated a predominantly solid-like behavior of the hydrogels with an increase in shear storage modulus with increasing cross-link density. The mechanical integrity of the PAA/hemicellulose hydrogels showed higher water swelling capacity and less fragility than the parent PAA hydrogels and they retained the heavy metal ion absorption ability of the PAA component, even in the presence of the least purified hemicellulose fraction.

  • 19.
    Galland, Sylvain
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Leterrier, Yves
    Nardi, Tommaso
    Plummer, Christopher J. G.
    Manson, Jan Anders E.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    UV-Cured Cellulose Nanofiber Composites with Moisture Durable Oxygen Barrier Properties2014Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, nr 16, s. 40604-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanocomposites based on 10 to 60 vol % cellulose nanofibers (NFC) in a photopolymerizable hyperbranched acrylate matrix were prepared. Unmodified NFC and NFC chemically modified with a silane coupling agent and with ceric ammonium nitrate for direct polymer grafting from the cellulose surface were used. A homogeneous dispersion of NFC in the matrix was obtained in each case, leading to a marked improvement in oxygen barrier (up to nine times) and thermomechanical properties (storage modulus increased up to seven times). The mechanisms involved in the permeability reduction were investigated, revealing non-monotonic trends in the evolution of the solubility and diffusion coefficients with NFC content. Most significantly, the inherent moisture sensitivity of the oxygen permeability of the NFC was found to be drastically reduced when it was dispersed in the polymer matrix, particularly after chemical modification, underlining the promise of the present approach for the production of robust, high barrier organic films.

  • 20. Gallstedt, M.
    et al.
    Hedenqvist, Mikael S.
    KTH, Tidigare Institutioner, Polymerteknologi.
    Packaging-related properties of alkyd-coated, wax-coated, and buffered chitosan and whey protein films2004Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 91, nr 1, s. 60-67Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Packaging-related properties of coated films of chitosan-acetic acid salt and whey protein concentrate (WPC) were studied. Chitosan (84.7% degree of deacetylation) and WPC (65-67% protein) were solution cast to films. These films are potential oxygen barriers for use in packaging. Coatings of wax or alkyds were used to enhance the water-barrier properties. The packaging-related properties of chitosan films treated in a buffering solution, with a pH of 7.8, were also investigated. The coated films were characterized with respect to Cobb absorbency, overall migration to water, water vapor transmission rate, and oxygen permeability. The creasability and bending toughness were determined. The wax was a more efficient barrier to liquid water and 90-95% relative humidity than the alkyd. However, the alkyd-coated material had superior packaging-converting properties. The alkyd-coated WPC and chitosan-salt films were readily folded through 180degrees without any visible cracks or delamination. The overall migration from the alkyd-coated materials was below the safety limit, provided the coat weight was higher than 7.5 mg/cm(2) on WPC and 2.1 mg/cm(2) on chitosan-salt. The barrier properties of chitosan film under moist conditions were improved by the buffer treatment. However, the buffering also resulted in shrinkage of the film.

  • 21. Gamstedt, E. Kristofer
    Effects of debonding and fiber strength distribution on fatigue-damage propagation in carbon fiber-reinforced epoxy2000Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 76, nr 4, s. 457-474Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to design new fatigue-resistant composites, the underlying fatigue damage mechanisms must be characterized and the controlling microstructural properties should be identified. The fatigue-damage mechanisms of a unidirectional carbon fiber-reinforced epoxy has been studied under tension-tension loading. A ubiquitous form of damage was one or a few planar fiber breaks from which debonds or shear yield zones grew in the longitudinal direction during fatigue cycling. This leads to a change in stress profile of the neighboring fibers, and an increase in failure probability of these fibers. The breakage of fibers in the composite is controlled by the fiber strength distribution. The interaction between the fiber strength distribution and debond propagation leading to further fiber breakage was investigated by a numerical simulation. It was found that a wider distribution of fiber strength and a higher debond rate lead to more distributed damage and a higher fracture toughness. Implications to fatigue life behavior are discussed, with reference to constituent microstructure.

  • 22. Groning, M.
    et al.
    Hakkarainen, Minna
    KTH, Tidigare Institutioner, Polymerteknologi.
    Headspace solid-phase microextraction with gas chromatography/mass spectrometry reveals a correlation between the degradation product pattern and changes in the mechanical properties during the thermooxidation of in-plant recycled polyamide 6,62002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 86, nr 13, s. 3396-3407Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The increased susceptibility of in-plant recycled polyamide 6,6 toward thermooxidation was shown by headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME/GC-MS), tensile testing, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). A correlation between the deterioration in mechanical properties and the formation of degradation products due to thermooxidation was found, and the most prominent decrease in mechanical properties coincided with the largest increase in the abundance of degradation products. The recycled materials had a shorter induction period toward oxidation, and their mechanical properties deteriorated faster than the mechanical properties of virgin material. The same trend was observed with HS-SPME/GC-MS because degradation products were found for recycled materials after oxidation times shorter than those for virgin material. Furthermore, larger amounts of degradation products were formed in the recycled materials. The high sensitivity of HS-SPME/GC-MS as an analytical tool was demonstrated because it was able to detect changes caused by oxidation considerably earlier than the other methods. Unlike DSC and FTIR, it could also show differences between samples recycled for different times. Four groups of degradation products-cyclic imides, pyridines, chain fragments, and cyclopentanones-were identified in thermooxidized polyamide 6,6. After 1200 h of thermooxidation, 1-pentyl-2,5-pyrrolidinedione was the most abundant degradation product. Approximately four times more 1-pentyl-2,5-pyrrolidinedione was formed in polyamide recycled three times than in virgin polyamide. Pyridines and chain fragments behaved toward oxidation and repeated processing like cyclic imides; that is, their amounts increased during oxidation, and larger amounts were formed in recycled materials than in virgin material. The cyclopentanone derivatives were present already in unaged material, and their amounts decreased during oxidation. Cyclopentanones were not formed because of the thermooxidation of polyamide 6,6.

  • 23. Haider, N.
    et al.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Loss and transformation products of the aromatic antioxidants in MDPE film under long-term exposure to biotic and abiotic conditions2002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 85, nr 5, s. 974-988Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The loss of a primary phenolic antioxidant Irganox 1010 and of a secondary phosphite antioxidant Irgafos 168 from a medium density polyethylene film (MDPE) was investigated after exposure of the film for 4 years to different environments such as aqueous media at pH5 and 7, open air, and compost, with an exposure of exposition of 25degreesC. An ultrasonic extraction technique using chloroform as extraction solvent was applied to recover the residual antioxidants from the polymeric matrix, and this was followed by High-Performance Liquid Chromatography (HPLC) with acetonitrile as mobile phase and a quantitative analysis at a wavelength of 280 run of the extracted antioxidants. The amount of antioxidant lost varied remarkably depending on the testing medium. The fastest loss of antioxidant was found on exposure to open air and sunlight while the slowest loss was observed in compost. Thermo-analytical measurements were made to characterize the residual thermo-oxidative stability of MDPE film in terms of oxidation temperature and oxidation induction time, to provide a greater insight into the underlying mechanisms of ageing in the different environments. Analysis by Gas chromatography-Mass Spectrometry (GC-MS) revealed that degradation of the polymeric matrix resulted in the formation of hydrocarbons and oxygen-containing compounds such as alcohols, carboxylic acids, aldehydes, and esters. The transformation products of the antioxidants formed as result of processing or exposure to the tested media were also identified. The transformation of the phenoxy radical of the Irganox 1010 produced the ester, acid, dealkylated cinnamate, and quinone products, whereas Irgafos 168 yielded oxidation products and the phenolic hydrolysis byproduct 2,4-ditert-butylphenol.

  • 24.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Susceptibility of starch-filled and starch-based LDPE to oxygen in water and air1997Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 66, s. 959-967Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    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.

  • 26.
    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.

  • 27.
    Hansson, Susanne
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Fogelström, Linda
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Toward Industrial Grafting of Cellulosic Substrates via ARGET ATRP2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 6, s. 41434-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For the past decade, the interest in controlled grafting of cellulose has increased immensely. Surface-Initiated Atom Transfer Radical Polymerization (SI-ATRP) has attracted the most interest; however, the sensitivity of this system has so far hindered its utilization in industry. In this study, filter paper, dissolving pulp, bleached and unbleached Kraft-pulp, and chemi-thermomechanical pulp papers were grafted with methyl methacrylate, employing activators regenerated by electron transfer (ARGET) ATRP. The reactions were performed in bulk or with small amounts of aqueous solutions, with no deoxygenation performed. To further demonstrate the robustness of this method towards simpler and more industry-friendly processes, the polymerizations were conducted in glass jars with screw lids. The possibility of recycling the reaction solution was also explored. We believe his thorough study to be an important step towards industrializing the "grafting-from" concept, and the results herein can most likely be extended to other surfaces and monomers.

  • 28.
    Hartman, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Söderqvist Lindblad, Margaretha
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Sjöberg, John
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Oxygen barrier materials from renewable sources: materials properties of softwood hemicellulose-based films2006Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 100, nr 4, s. 2985-2991Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to investigate the film-forming ability of the hemicellulose O-acetyl-galactoglucomannan (AcGGM) and to evaluate its potential as a barrier material. The polymer film was evaluated by measurement of its oxygen permeability (Ox-Tran® Mocon), thermal properties (differential scanning calorimetry), and dynamic mechanical properties under a humidity scan (humidity-scan DMA). The AcGGM was isolated from industrial process water obtained from mechanical wood pulping. The self-supporting films were formed by solution-casting from water. As expected, a plasticizer was needed to avoid brittleness, and glycerol, sorbitol, and xylitol were compared. However, these additives resulted in higher sensitivity to moisture, which might be less beneficial for some applications. Interesting oxygen barrier and mechanical strength properties were achieved in a film obtained from a physical blend of AcGGM and either alginate or carboxymethylcellulose, both having a substantially higher molecular weight than AcGGM. No phase separation was observed, since all the components used were rich in hydroxyl functionalities. When a plasticizer was also added to the binary mixture, a compromise between (1) low O2 permeability, (2) high mechanical toughness, and (3) flexibility of an AcGGM-based film was obtained.

  • 29.
    Hedenqvist, Mikael S.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Merveille, A.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Bergman, G.
    Adhesion of microwave-plasma-treated fluoropolymers to thermoset vinylester2005Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 98, nr 2, s. 838-842Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Poly(tetrafluoroethylene) and a fluoroethylene copolymer were surface treated with a 2.45-GHz microwave plasma to enhance their adhesion to a vinylester thermoset. The plasmas were generated with an inert gas (Ar) and with reactive gases (H-2, O-2, and N-2). The lap-joint shear stress was measured on fluoropolymer samples glued with the vinylester. In general, the stress at failure increased with increasing plasma-energy dose. The H, plasma yielded the best adhesion, and X-ray photoelectron spectroscopy revealed that it yielded the highest degree of defluorination of the fluoropolymer surface. The defluorination efficiency declined in the order H-2, Ar, O-2, and N-2. Contact angle measurements and scanning electron microscopy revealed that the surface roughness of the fluoropolymer depended on the rate of achieving the target energy dose. High power led to a smoother surface, probably because of a greater increase in temperature and partial melting.

  • 30.
    Hedenqvist, Mikael S.
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Ritums, J. E.
    Conde-Brana, M.
    Bergman, G.
    Sorption and desorption of tetrachloroethylene in fluoropolymers: Effects of the chemical structure and crystallinity2003Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 87, nr 9, s. 1474-1483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In 18 fluoropolymers with different repeating-unit structures and crystallinities, the solubility, diffusivity, and permeability at 70degreesC of a polarizable nonpolar solute (tetrachloroethylene) were studied. The transport properties were mostly controlled by the polarity of the polymer and to a lesser degree by the polymer crystallinity. The highest permeability was observed in the dipole-containing ethylene-chlorotrifluoroethylenes because of their high tetra chloroethylene solubility. The lowest permeability was observed in the hydrogen-bonding poly(vinylidene fluoride) polymers because of the combination of low solute solubility and solute diffusivity. The tetrachloroethylene diffusivity was solute-concentration-dependent, and sorption curves were S-shaped, indicating that the solute surface concentration was time-dependent. The rate at which the surface concentration approached the saturation level was proportional to the product of Young's modulus, the square of the thickness of the dry polymer, and the logarithm of the solute diffusivity. Data for the water-hyperbranched polymer and limonene-polyethylene conformed to the same relationship. Therefore, this provides a new tool for predicting the solute-surface-concentration time dependence from data obtained by independent measurements.

  • 31.
    Henriksson, Marielle
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Structure and Properties of Cellulose Nanocomposite Films Containing Melamine Formaldehyde2007Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 106, nr 4, s. 2817-2824Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Films of high Young's modulus and low density are of interest for application as loudspeaker membranes. In the present study nanocomposite films were prepared from microfibrillated cellulose (MFC) and from MFC in combination with melamine formaldehyde (MF). The prepared materials were Studied with respect to structure as well as physical and mechanical properties. Studies in SEM and calculation of porosity showed that these materials have a dense paper-like structure. The moisture sorption isotherms were measured and showed that Moisture content decreased in the presence of ME Mechanical properties were studied by dynamical mechanical thermal measurements as well as by tensile tests. Cellulose films showed an average Young's modulus of 14 GPa while the nanocomposites showed an average Young's modulus as high as 16.6 GPa and average tensile strength as high as 142 M.Pa. By controlling composition and structure, the range of properties of these materials can extend the property range available for existing materials. The combination of comparatively high mechanical damping and high sound propagation velocity is of technical interest.

  • 32.
    Ihrner, Niklas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Johansson, Mats
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Improved performance of solid polymer electrolytes for structural batteries utilizing plasticizing co-solvents2017Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 134, nr 23, artikkel-id 44917Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study describes the formulation, curing, and characterization of solid polymer electrolytes (SPE) based on plasticized poly(ethylene glycol)-methacrylate, intended for use in structural batteries that utilizes carbon fibers as electrodes. The effect of crosslink density, salt concentration, and amount of plasticizer has been investigated. Adding a plasticizing solvent increases the overall performance of the SPE. Increased ionic conductivity and mechanical performance can be attained compared to similar systems without plasticizer. At ambient temperature, ionic conductivity (sigma) of 3.3 x 10(-5) Scm(-1), with a corresponding storage modulus (E) of 20 MPa are reached.

  • 33. Jebrane, Mohamed
    et al.
    Cai, Shengzhen
    Panov, Dmitri
    Yang, Xi
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Terziev, Nasko
    Synthesis and characterization of new vinyl acetate grafting onto epoxidized linseed oil in aqueous media2015Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 132, nr 24, artikkel-id 42089Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modified poly (vinyl acetate) copolymers with epoxidized linseed oil (ELO) as co-monomer have been prepared. The polymerization was performed in aqueous medium without any additional protective colloid in the presence of sodium persulfate as catalyst. The effect of vinyl acetate (VAc)/ELO feed ratio, reaction temperature, reaction time, and catalyst amount has been studied. FTIR spectroscopy showed that the reaction between ELO and VAc resulted in slight decrease and shift in ELO characteristic bands of oxirane groups; and new bands were detected in the copolymer spectra attributed to PVAc and ELO functional groups. Moreover, new signals attributable to the copolymer were observed in the H-1 NMR spectra ( 4.07 and 1.62 ppm) and in the C-13 NMR spectra ( 15.29 and 31.0 ppm). Analysis by differential scanning calorimetry (DSC) showed a single T-g for the copolymerization product of VAc and ELO and two T-g for the PVAc/ELO blend, indicating the chemical reaction between VAc and ELO.

  • 34.
    Jerpdal, Lars
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. Volkswagen AG, Grp Res, D-38440 Wolfsburg, Germany..
    Schuette, Philipp
    Volkswagen AG, Grp Res, D-38440 Wolfsburg, Germany..
    Stahlberg, Daniel
    Scania CV AB, SE-15187 Sodertalje, Sweden..
    Åkermo, Malin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Dept Aeronaut & Vehicle Engn, SE-10044 Stockholm, Sweden..
    Influence of temperature during overmolding on the tensile modulus of self-reinforced poly(ethylene terephthalate) insert2019Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, artikkel-id 48334Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-reinforced polymer composites are thermoplastic materials for design of recyclable lightweight components. The combination of sheet forming and subsequent overmolding from these materials allows an efficient manufacturing process with function integration. This article investigates how temperature exposure during an overmolding cycle influences the tensile modulus, shrinkage, and warpage for an insert made from self-reinforced poly(ethylene terephthalate) (PET) when it is overmolded with polycarbonate (PC)/PET material. The temperature gradient that is induced by overmolding is simulated, and the results are validated through experiments. The results show that the insert reaches a temperature above the glass-transition temperature for the matrix material in the main part of the insert, which leads to relaxation of residual stresses and thereby a reduction of the tensile modulus up to 18% for the insert after overmolding. Even though overmolding is an efficient process, it requires thorough knowledge of how temperature influences the material when applied to self-reinforced composite materials. The study shows very interesting results, which can lead to new areas of applications for self-reinforced PET. 

  • 35.
    Johansson, Mats K. G.
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Glauser, T.
    Rospo, G.
    Hult, Anders
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Radiation curing of hyperbranched polyester resins2000Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 75, nr 5, s. 612-618Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A research area that has obtained increasing interest during the last decade concerns improvement of macromolecular properties by changes in the macromolecular architecture. One group of these materials is dendritic polymers, which are highly branched structures exhibiting very different properties compared with linear polymers. One potential application for these polymers is as radiation curable thermoset resins. This article describes a study where the use of an aliphatic hyperbranched polyester as a base for new radiation curable thermoset resins. The hyperbranched polyesters have been characterized with respect to cure rate and final mechanical properties compared with conventional resins. It is shown that hyperbranched polyesters can be used as versatile scaffolds for various radiation curable resin structures.

  • 36.
    Jonsson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Nordin, Ove
    Larsson Kron, Anna
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Increased Onset Temperature of Expansion in Thermally Expandable Microspheres from Combination of Crosslinking Agents2011Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 121, nr 1, s. 369-375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Free-radical suspension polymerization was used to synthesize thermally expandable microspheres (TEMS) in which a poly(acrylonitrile-co-methacrylonitrile) shell encapsulates isooctane. TEMS were prepared with 1,4-butanediol dimethacrylate (BDDMA), in combination with 1,4-butanediol divinyl ether (BDDVE), diallyl carbonate (DAC), or allyl methacrylate, as crosslinkers. It was found that a significant increase in the onset temperature of expansion (T-start) could be obtained when a combination of BDDMA and BDDVE or DAC was used, compared to when only BDDMA was used as crosslinker. The expansion capacity of the TEMS was excellent when BDDMA and DAC were combined. One benefit of the increased T-start was demonstrated when poly(vinyl chloride)-plastisols containing TEMS could be cured at higher temperatures without premature expansion. The differences in expansion obtained with different combinations of crosslinkers originate from the difference in reactivity of the vinyl-functionalities of the crosslinkers, which regulate the incorporation of the crosslinker into the polymer and thereby, the mechanical properties of the microsphere shell.

  • 37.
    Jonsson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Nordin, Ove
    Larsson Kron, Anna
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Influence of Crosslinking on the Characteristics of Thermally Expandable Microspheres Expanding at High Temperature2010Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 118, nr 2, s. 1219-1229Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Free-radical suspension polymerization was used to synthesize thermally expandable microspheres (TEMS); in this process, a poly(acrylonitrile-co-methacrylonitrile) shell encapsulated isooctane. Different amounts of dimethacrylate, diacrylate, or divinyl ether functional crosslinker were added to investigate the effects on the crosslinking density of the polymer and the expansion properties of the TEMS. The optimum amount of crosslinker was found to be approximately 0.05-0.1 mol %. However, a significantly better expansion could be obtained with 1,4-butanediol dimethacrylate as a crosslinker, compared to 1,4-butanediol divinyl ether or 1,4-butanediol diacrylate. From monitoring the conversion of monofunctional analogues by gas chromatography, we suggest that the differences in expansion obtained with different crosslinkers, originated from the difference in the reactivity of the radicals in the system toward the vinyl functionalities of the crosslinkers. This regulated the incorporation of the crosslinker into the polymer and, thereby, the mechanical properties of the microsphere shell.

  • 38.
    Jonsson, Magnus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Nordin, Ove
    Larsson Kron, Anna
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Thermally Expandable Microspheres with Excellent Expansion Characteristics at High Temperature2010Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 117, nr 1, s. 384-392Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermally expandable core/shell particles with a poly(acrylonitrile-co- methacrylonitrile) shell and a hydrocarbon core (blowing agent) have been prepared by suspension polymerization. The objective of this study was to gain a deeper understanding of the parameters determining the expansion properties of these microspheres. It was found that the amount, the boiling point, and the structure of the blowing agent are important parameters for the expansion properties. For example, a higher maximum expansion was reached when using bulkier blowing agents and thus a lower diffusion rate through the polymer shell. Further, the amount and structure of the crosslinker were also found to be essential for the expansion properties. For this particular system, it was found that a dimethacrylate-functional crosslinker gave significantly better expansion when compared with diacrylate-or divinylether-based crosslinkers. Beside these parameters, it was also observed that the particle-size distribution influence the expansion properties of the microspheres.

  • 39.
    Kaali, Peter
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Momcilovic, Dane
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Markstrom, Agneta
    Aune, Ragnhild E.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Czel, Gyorgy
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Degradation of Biomedical Polydimethylsiloxanes During Exposure to In Vivo Biofilm Environment Monitored by FE-SEM, ATR-FTIR, and MALDI-TOF MS2010Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, nr 2, s. 802-810Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymers used for biomedical purposes in medical devices are usually requested to be inert to degradation. This article describes that slow irreversible changes were observed in silicone surfaces exposed to in vivo biofilms even if silicone, in general, is supposed to have excellent long-term properties. Tracheostomy tubes made of silicone rubber were exposed to in vivo biofilm environments in clinical tests for periods of 7, 3, and 6 months. The chemical degradation was monitored by MALDI-TOF MS, ATR-FTI.R, and FE-SEM. In addition, the physical changes were monitored by contact angle and hardness measurements. Cyclic polydimethylsiloxane (PDMS) was detected on the surfaces of new (unaged) silicones. On the surfaces of the in vivo samples new compounds, presumably linear methyl-hydroxyl-terminated PDMS, were detected in addition to cyclic PDMS. These compounds may be formed as a result of the hydrolysis of linear dimethyl terminated PDMS, which is also present in the silicone rubber. ATR-FTIR spectroscopy confirmed that hydrolysis had indeed occurred during the in vivo exposure, since Si-OH groups were detected. Furthermore, significant changes in the topography were detected by FE-SEM, indicating the initiation of degradation. No significant changes in the contact angle of the in vivo used samples were observed, but this information may be shielded by the fact that biofilm may remain on the surface, despite the thorough cleaning before the analysis. It is also possible that the surface hydrophobicity was recovered by the diffusion of linear low-molecular-weight compounds from the bulk.

  • 40. Karlsson, A.
    et al.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    A new method for the determination of a hydrosilanization inhibitor applied to measurements during curing of a silicone elastomer2001Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 79, nr 13, s. 2349-2353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new method for the quantitative determination of the hydrosilylation inhibitor 1-ethynyl-1-cyclohexanol in a poly(dimethyl siloxane) matrix is presented. The method is based on headspace gas chromatography directly from the semisolid sample without solvent addition. The method was found to be both selective and sensitive. The relative standard deviation of the method was estimated to be 6%. The semisolid silicone sample was weighed directly in a headspace autosampler vial. After sample equilibration at 90 degreesC for 1 h, the gas phase was injected into a gas chromatography system with a nonpolar methyl silicone capillary column. The inhibitor was detected with a flame ionization detector. The standard addition procedure was used for quantification. Recovery data on the inhibitor from the silicone during curing suggests that the inhibitor reacts with the silicone hydride crosslinker in the presence of the platinum catalyst to become part of the polymer network. This implies that the inhibitor will not migrate out from the silicone elastomer, which is a great advantage particularly for silicone elastomers used for medical devices or controlled drug release applications.

  • 41. Karlsson, A.
    et al.
    Singh, S. K.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Controlled destruction of residual crosslinker in a silicone elastomer for drug delivery2002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 84, nr 12, s. 2254-2264Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In drug delivery systems that use silicone elastomers as a diffusion matrix for the active drug, it is common to crosslink the material by the hydrosilylation reaction. In this platinum-catalyzed reaction, vinyl groups on a polymer add to the methyl siloxane hydride (MHS) groups on a low molecular mass crosslinker. With an excess of crosslinker, a fast curing is achieved and a fully crosslinked material is formed. Unreacted MHS groups were shown to remain in the elastomer after curing because of the excess crosslinker. In this work, a simple procedure was developed to eliminate the unreacted MHS groups from the final product. We found that storage of the product at +40degrees and 75% relative humidity for a few weeks will effectively destroy the residual MHS groups in the elastomer. The effects of varying levels of humidity, oxygen, and temperature on this postcuring procedure were studied. The amount of MHS groups was measured with NMR and IR spectroscopy. We also found that the hardness of the material increased by approximately 25% as a consequence of this postcuring treatment. This increase is probably due to a secondary crosslinking reaction between MHS and silanol groups. Heat treatment at higher temperatures led to an even further increase in the hardness and compression modulus. Because no MHS groups remained in the elastomer when this heat treatment was started, it is apparent that another secondary crosslinking reaction is occurring, probably silanol condensation.

  • 42. Khabbaz, F.
    et al.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Rapid test methods for analyzing degradable polyolefins with a pro-oxidant system2001Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 79, nr 12, s. 2309-2316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemiluminescence, size exclusion chromatography, differential scanning calorimetry, thermogravimetry, and Fourier transform infrared spectroscopy were used to assess differences in oxidation rate between two different pro-oxidant systems in degradable low-density polyethylene. The pro-oxidant formulation used consisted of manganese stearate and natural rubber or manganese stearate and a synthetic, styrene-butadiene copolymer rubber. The low-density polyethylene containing the prooxidant with natural rubber showed the highest degradation rate. Chemiluminescence and thermogravimetry were found to be the most effective techniques for establishing the differences between different pro-oxidant systems.

  • 43. Khabbaz, F.
    et al.
    Karlsson, Sigbritt
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Py-GC/MS an effective technique to characterizing of degradation mechanism of poly (L-lactide) in the different environment2000Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 78, nr 13, s. 2369-2378Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The biotic and abiotic degradation of poly (L-lactide) (PLLA) has been studied with pyrolysis gas chromatography mass spectrometry (Py-GC-MS). A mixed culture of compost micro-organisms was used as the biotic medium. Size-exclusion chromatography (SEC), gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were utilized to monitor the degradation and degradation mechanism. Differences in pH, molecular weight, surface structure, and degradation mechanisms were noted between sample aged in biotic and abiotic medium. Using fractionated Py-GC-MS at 400 and 500 degreesC, acetaldehyde, acrylic acid, lactoyl acrylic acid, two lactide isomers, and cyclic oligomers up to the pentamer were identified as thermal decomposition products of PLA as well as some other not completely identified products. The ratio of meso-lactide to L-lactide was lower in the sample aged in the biotic media than the abiotic media. This is a result of the preference of the micro-organisms for L-form of lactic acid and lactoyl lactic acid rather than the D-form that in turn influences the formation and the amounts of meso and D,L-lactide during the pyrolysis. Based on SEM micrographs, it was shown that degradation in the biotic medium proceeded mainly via a surface erosion mechanism, whereas bulk erosion was the predominant degradation mechanism in the abiotic medium. The SEC and Py-GC-MS data indicate that degradation was faster in the biotic than in the abiotic sample.

  • 44. Kikionis, Stefanos
    et al.
    Ioannou, Efstathia
    Andrén, Oliver C. J.
    Chronakis, Ioannis S.
    Fahmi, Amir
    Malkoch, Michael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Toskas, Georgios
    Roussis, Vassilios
    Nanofibrous nonwovens based on dendritic-linear-dendritic poly(ethylene glycol) hybrids2018Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 135, nr 10, artikkel-id 45949Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dendritic-linear-dendritic (DLD) hybrids are highly functional materials combining the properties of linear and dendritic polymers. Attempts to electrospin DLD polymers composed of hyperbranched dendritic blocks of 2,2-bis(hydroxymethyl) propionic acid on a linear poly(ethylene glycol) core proved unsuccessful. Nevertheless, when these DLD hybrids were blended with an array of different biodegradable polymers as entanglement enhancers, nanofibrous nonwovens were successfully prepared by electrospinning. The pseudogeneration degree of the DLDs, the nature of the co-electrospun polymer and the solvent systems used for the preparation of the electrospinning solutions exerted a significant effect on the diameter and morphology of the electrospun fibers. It is worth-noting that aqueous solutions of the DLD polymers and only 1% (w/v) poly(ethylene oxide) resulted in the production of smoother and thinner nanofibers. Such dendritic nanofibrous scaffolds can be promising materials for biomedical applications due to their bio-compatibility, biodegradability, multifunctionality, and advanced structural architecture.

  • 45. Kornmann, X.
    et al.
    Thomann, R.
    Mulhaupt, R.
    Finter, J.
    Berglund, Lars A.
    Synthesis of amine-cured, epoxy-layered silicate nanocomposites: The influence of the silicate surface modification on the properties2002Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 86, nr 10, s. 2643-2652Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fluorohectorites were rendered organophilic through the cation exchange of sodium intergallery cations for protonated monoamine, diamine, and triamine oligopropyleneoxides and octadecylamine, benzylamine, and adducts of octadecylamine and benzylamine with diglycidyl ether of bisphenol A (DGEBA). The influence of the silicate surface modification and compatibility on the morphology and thermal and mechanical properties was examined. Surface modification with protonated octadecylamine and its adduct with DGEBA promoted the formation of microscale domains of silicate layers separated by more than 50 Angstrom, as evidenced by transmission electron microscopy and wide-angle X-ray scattering. Young's modulus of these two nanocomposites increased parabolically with the true silicate content, whereas conventionally filled composites exhibited a linear relationship. The highest fracture toughness was observed for conventionally filled composites.

  • 46. Larsson, Karolina
    et al.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Ankerfors, Mikael
    Lindström, Tom
    Polylactide latex/nanofibrillated cellulose bionanocomposites of high nanofibrillated cellulose content and nanopaper network structure prepared by a papermaking route2012Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 125, nr 3, s. 2460-2466Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous attempts to use polylactide (PLA) latex particles and nanofibrillated cellulose (NFC) in papermaking processing have been limited to low NFC content. In the present study, a bionanocomposite material was successfully produced using a PLA latex and NFC. The components were mixed using a wet mixing method and bionanocomposite films were made by filtration followed by hot pressing. In composite materials, the dispersion of the reinforcing component in the matrix is critical for the material properties. Biopolymers such as PLA are non-polar and soluble only in organic solvents; NFC is, however, highly hydrophilic. By utilizing latex, i.e., an aqueous dispersion of biopolymer micro-particles, wet mixing is possible and the problem of aggregation of the hydrophilic nanocellulose in organic solvent is avoided. The properties of the resulting NFC/PLA latex bionanocomposite films were analyzed. Thorough blending resulted in good dispersion of the reinforcing component within the matrix. Adding increasing amounts of NFC improved the Young's modulus, tensile strength, and strain at break of the bionanocomposite material. The increase in the tensile properties was linear with increasing NFC content as a result of the good dispersion. The NFC also improved the thermal stability of the bionanocomposite material.

  • 47. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Eklund, Patrik
    Lucenius, Jessica
    Österberg, Monika
    Willför, Stefan
    Targeted functionalization of spruce O-acetyl galactoglucomannans-2,2,6,6-tetramethylpiperidin-1-oxyl-oxidation and carbodiimide-mediated amidation2013Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 130, nr 5, s. 3122-3129Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modified spruce O-acetyl galactoglucomannans (GGMs) can be used as molecular anchors to alter the surface properties or to activate the surface of cellulose. To selectively introduce functionalities, GGMs were oxidized on C-6 of hexoses by 2,2,6,6-tetramethylpiperidin-1-oxyl-mediated oxidation. Different degrees of oxidation were successfully obtained by varying the reaction parameters. Low degrees could be obtained by performing the oxidations in bromide-free conditions. The formed uronic acids were further modified by a carbodiimide-mediated amidation reaction, which opens a window for introducing various functionalities selectively on hexoses. The adsorption of the modified GGMs to various cellulose samples was investigated. Indirect bulk sorption to fibers was compared to direct adsorption to nanofibrillated cellulose ultrathin films. GGMs with low degrees of oxidation showed high affinity to cellulose surfaces and could be sorbed onto cellulose in pure water. Moderate amounts of GGMs with high degree of oxidation could be sorbed onto cellulose in the presence of salts.

  • 48.
    Lindqvist, Josefina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Surface Modification of Natural Substrates by Atom Transfer Radical Polymerization2006Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 100, nr 5, s. 4155-4162Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surface modification of various solid polysaccharide substrates was conducted by grafting methyl acrylate (NU,) and styrene via atom transfer radical polymerization (ATRP) to produce well-defined polymer grafts. The hydroxyl groups on the surfaces of the substrates were reacted with 2-bromoisobutyryl bromide followed by graft copolymerization under ATRP conditions. The studied substrates were filter paper, microcrystalline cellulose, Lyocell fibers, dialysis tubing, and chitosan films. The modified Substrates were analyzed by FT-IR, water contact angle measurements, TGA, and SEM. FT-IR characterization of the grafted substrates showed significant differences between the different substrates in the amount of grafted polymer. Higher amounts of polymer seem to be possible to graft from native cellulose substrates than from regenerated cellulose substrates. To investigate whether the grafted polymers were "living" after a longer time period, a second layer of polystyrene was grafted from a filter paper modified with PMA one year ago. FT-IR characterization of the filter paper showed a peak corresponding to styrene, indicating that a block copolymer had been formed on the surface. Graft copolymerization can be used to change and tailor the surface properties of the polysaccharide substrates.

  • 49.
    Lindström, Annika
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Environmentally friendly plasticizers for poly(vinyl chloride)- Improved mechanical properties and compatibility by using branched poly(butylene adipate) as a polymeric plasticizer2006Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 100, nr 3, s. 2180-2188Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Linear and branched poly(butylene adipate)s (PBA) with molecular weights ranging from 2000 to 10,000 g/mol, and a branching agent content between 0 and 1.8%, were solution cast with poly(vinyl chloride) (PVC) to form 50- to 60-mu m thick flexible films. Dry films were analyzed by tensile testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and optical microscopy (OM) to study the effects of molecular weight and branching on the plasticizing efficiency of the polyester. PBA formed a semimiscible two-phase system with PVC, where the amorphous part exhibited a single glass transition temperature. The degree of crystallinity for the polyester, Surface composition, and mechanical properties of the films depended on the blend composition, molecular weight, and degree of branching of the polyester. Plasticizing efficiency was improved by higher degree of branching.

  • 50.
    Lindström, Annika
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Migration-resistant polymeric plasticizer for poly(vinyl chloride)2007Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 104, nr 4, s. 2458-2467Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Flexible films of poly(vinyl chloride) (PVC) and linear or branched poly(butylene adipate) (PBA), synthesized from 1,4-butanediol and adipic acid or dimethyl ester of adipic acid, were aged in an aqueous environment for 10 weeks to study how branching, molar mass, and end-group functionality affect the leaching of polyester plasticizer from thin films. Principal component analysis was applied to reveal patterns and correlations between mechanical properties, material characteristics, and aging behavior. Introduction of branches in the polyester structure increased the miscibility between PVC and the polyester, resulting in improved mechanical properties and lower water absorption. Methyl ester end-group in PBA polyester stabilized the polymeric plasticizer toward hydrolysis, and reduced the formation and migration of monomeric degradation products from the blends during aging in water. The combination of branched structure with methyl ester end-groups resulted in a migration resistant polymeric plasticizer.

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