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  • 1.
    Blomfeldt, Thomas O. J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Olsson, Richard T.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Menon, Mohan
    Plackett, David
    Johansson, Eva
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Novel Foams Based on Freeze-Dried Renewable Vital Wheat Gluten2010In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 295, no 9, p. 796-801Article in journal (Refereed)
    Abstract [en]

    A new way of producing rigid or semi-rigid foams from vital wheat gluten using a freeze-drying process is reported. Water/gluten-based mixtures were frozen and freeze-dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 mm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed that the foams rapidly soaked up the liquid. An especially interesting feature of the low-wheat-concentration foams was the "in situ'' created soft-top-rigid-bottom foams.

  • 2. Glauser, T.
    et al.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Kornmann, X.
    Berglund, Lars A.
    Toughening of electron-beam cured acrylate resins2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 280, no 08-jul, p. 20-25Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to improve the toughness of EB-cured acrylate thermost resins by using hyperbranched aliphatic polyesters as additives to obtain a liquid-liquid phase-separated resin. The hyperbranched polyester can be considered as a hydroxyl functional scaffold, on which functional groups were reacted by control phase separation and crosslinking. Alkyl chains of different lengths attached to the scaffold controlled phase separation. The amount of crosslinking within the rubbery particle and between the particles and the matrix was set by the percentage of methacrylate groups. A good phase separation was obtained; therefore, T-g decreased only slightly compared to the pure acrylate. The K-IC value of the cured resins was increased by 30%. The phase-separated resins showed stability with time and no significant increase in particle size was noticed after 18 months.

  • 3. Glauser, T.
    et al.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    A comparison of radiation and thermal curing of thick composites2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 274, no 1, p. 25-30Article in journal (Refereed)
    Abstract [en]

    This work aimed to compare three different techniques to cure thick composite matrices to see the effect of the process on the network and the thermomechanical properties of the polymer matrix. Two different thermoset resins. one acrylate and one methacrylate, have been free-radically cured with high-energy electron beam (EB), ultra-violet light (UV) ol heat (thermal). The differences in curing mechanisms as well as the thermomechanical properties of the cured resins have been investigated. For this type of resins, EB-cured samples showed the highest thermo-mechanical properties and the lowest residual unsaturation. Thermally cured resins showed similar properties, but with drawbacks such as long curing cycles and thermal degradation in the matrix. The cure did not proceed to the same extent in the UV-cured samples. But the simplicity of the curing equipment makes UV-curing an interesting complement to thermal or EB-curing.

  • 4. Glauser, T.
    et al.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Electron-beam curing of thick thermoset composites: Effect of temperature and fiber2000In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 274, no 1, p. 20-24Article in journal (Refereed)
    Abstract [en]

    Electron-beam curing of thermoset resins used in fiber-reinforced composites has been investigated. Two resins, a bisphenol-A acrylate and methacrylate, were used as model systems. The temperature was monitored during cure to know the thermal history of the composite during cure. The thermo-mechanical properties were measured on the cured samples. It could be seen that all these values were influenced by the nature (glass or carbon) and amount (0-50 wt.-%) of fiber. A linear correlation was found between the maximum temperature during cure and the glass transition temperature. It was shown that it is possible to compensate for alack of heat during dire in systems with too low exotherms. Some influence on the network homogeneity was also noticed when the thermal energy available during cure was too low.

  • 5.
    Khosravi, Sara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Khabbaz, F.
    Nordqvist, Petra
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Wheat-gluten-based adhesives for particle boards: Effect of crosslinking agents2014In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 299, no 1, p. 116-124Article in journal (Refereed)
    Abstract [en]

    WG proteins show potential as environmentally friendly replacements for amino/formaldehyde resins in particle boards. The performance of WG dispersions in combination with crosslinkers as adhesives for particle boards is studied. The WG dispersions are prepared with sodium hydroxide or citric acid as the dispersing agent. Polyamidoamine-epichlorohydrin (PAAE) and trimethylolpropane triacetoacetate (AATMP) are employed as crosslinkers. The performance of the WG dispersions and the crosslinkers are evaluated based on board properties, i.e., internal bond, thickness swelling, and water absorption. The results show an enhanced performance of WG using PAAE as crosslinker. The results reveal it is advantageous to disperse WG in sodium hydroxide compared to citric acid. The potential of crosslinked wheat-gluten-based adhesives for particle boards is demonstrated. The effect of parameters such as crosslinking type and pH is described. A formaldehyde-free particle board adhesive is thus obtained.

  • 6. Krupicka, A.
    et al.
    Johansson, Mats K. G.
    KTH, Superseded Departments, Polymer Technology.
    Hult, Anders
    KTH, Superseded Departments, Polymer Technology.
    Viscoelasticity in polymer films on rigid substrates2003In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 288, no 2, p. 108-116Article in journal (Refereed)
    Abstract [en]

    The viscoelasticity of two thermally crosslinked polymer coatings was examined in terms of relaxation of the applied stress after a sudden strain. Two different transient methods were utilized: flat-ended cylindrical indentation testing of polymer film on a rigid substrate and tensile testing of a corresponding free-standing polymer film. The correlation between tensile and indentation tests was studied. The mechanical response of a viscoelastic layer deposited on a rigid substrate was investigated as a function of indentation depth. there was good agreement between the results of the tensile and indentation tests for thick film layers at moderate indentation depths. The findings indicate that the substrate influences the coating performance by reducing the viscous contribution to the stress response hand amplifying the magnitude of the equilibrium modulus for large indentation depths. The indentation method utilized here was shown to be a potentially suitable tool for the determination of Poisson's ratio of polymer films.

  • 7. Liu, X. H.
    et al.
    Wu, Q. J.
    Berglund, Lars A.
    Qi, Z. N.
    Investigation on unusual crystallization behavior in polyamide 6/montmorillonite nanocomposites2002In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 287, no 8, p. 515-522Article in journal (Refereed)
    Abstract [en]

    The crystallization behavior and crystal structure of polyamide 6/montmorillonite (PA6/MMT) nanocomposites were investigated by differential scanning calorimetry and X-ray diffraction, and an interesting behavior was observed. The material was prepared via melt compounding using an organophilic clay obtained by co-intercalation of epoxy resin and quaternary ammonium into Na-montmorillonite. A maximum in degree of crystallinity was obtained at 5 wt.-% MMT and the reasons for this, based on the MMT layer distribution, were discussed. The degree of crystallinity showed a strong dependence on the cooling rates. In contrast with typical behavior, a higher cooling rate resulted in a higher degree of crystallinity. In nanocomposites, the gamma-crystalline phase was dominant.

  • 8. Meszynska, Anna
    et al.
    Pollet, Eric
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Averous, Luc
    Effect of Oligo-Hydroxyalkanoates on Poly(3-Hydroxybutyrate-co-4-Hydroxybutyrate)-Based Systems2015In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 300, no 6, p. 661-666Article in journal (Refereed)
    Abstract [en]

    This study presents the utilization of oligo-hydroxyalkanoates obtained from controlled degradation of poly(3-hydroxybutyrate) as additives in a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer matrix (P(3HB-co-4HB)). These oligomers are compared to a conventional biobased plasticizer, used as reference, based on a monoglyceride acetate obtained from hydrogenated castor oil. Different multiphase systems are elaborated with these additives and characterized. Thermal and mechanical properties demonstrate that the monoglyceride acetate is as an efficient plasticizer increasing the elongation of the P(3HB-co-4HB) films while decreasing their maximum strength and elastic modulus. On the contrary, the addition of oligo-PHB results in an increased crystallinity of the matrix, thus improving the maximum strength and elastic modulus of the corresponding films. The oligomers act as an efficient reinforcing agent. Mobility brought by the oligomers induces a rearrangement of the P(3HB-co-4HB) with an increase of the chain rearrangement. Interestingly, the simultaneous addition of both additives results in significantly reduced T-g and improved elongation at break, as expected from an efficient plasticizer, but it also leads to P(3HB-co-4HB) films retaining relatively high strength and modulus values, thanks to the reinforcement ability of the oligo-PHB additive. Thermal characterization finally demonstrated that such mixed additives system results in greatly improved thermal stability of the polyhydroxyalkanoate copolymer matrix.

  • 9. Sakai, Reika
    et al.
    Baiju, John
    Okamoto, Masami
    Seppälä, Jukka V
    Vaithilingam, Jayasheelan
    Hussein, Husnah
    Loughborough University, United Kingdom .
    Goodridge, Ruth
    Fabrication of Polylactide-Based Biodegradable Thermoset Scaffolds for Tissue Engineering Applications2013In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 298, no 1, p. 45-52Article in journal (Refereed)
    Abstract [en]

    The fabrication of tissue engineering scaffolds based on the polymerization of crosslinked polylactide using leaching and batch foaming to generate well-controlled and interconnected biodegradable polymer scaffolds is reported. The scaffold fabrication parameters are studied in relation to the interpore connectivity, pore morphology, and structural stability of the crosslinked PLA scaffold. In vitro cell culture and in vitro degradation are used to analyze the biocompatibility and biodegradability of the scaffolds. The new crosslinked PLA thermoset scaffolds are highly suitable for bone tissue engineering applications due to their complex internal architecture, thermal stability, and biocompatibility.

  • 10. Schmid, Daniel
    et al.
    Handge, Ulrich A.
    Gann, John P.
    Yan, Mingdi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Caseri, Walter
    Melt elongation of polymer nanocomposites: A method for the controlled production of dichroic films2008In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 293, no 6, p. 471-478Article in journal (Refereed)
    Abstract [en]

    A processing method based on stretching of molten polymer nanocomposites was applied to prepare dichroic films. First, dodecanethiol-capped gold particles were embedded in low density polyethylene. The resulting isotropic films were stretched in the melt under uniaxial loading using an elongational rheometer. The melt elongation technique resulted in reproducible characteristics of the optical properties and can be directly transferred to an industrial scale. The organic coating of the metal particles plays an important role in the generation of the dichroism. A reactive surface (adsorbed perfluorophenyl azide) led to strongly agglomerated particles which obviously did not lead to dichroic films.

  • 11.
    Ståhlberg, Daniel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Marklund, Erik
    Nordin, Lars-Olof
    Varna, Janis
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mechanical response of thermoset polymers under high compressive loads, 2: Modeling2005In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 290, no 11, p. 1073-1082Article in journal (Refereed)
    Abstract [en]

    A nonlinear viscoelastic material model was used to describe the experimental behaviour of thin vinyl ester specimens Subjected to compression in thickness direction. The stress-dependent material functions in the model were found in creep and strain recovery tests on thick cylindrical specimens. The elastic and creep response of thin thermoset polymer specimens subjected to compressive loads was simulated while varying the geometry of the test set samples. The calculated increase in the apparent elastic modulus and decrease of the creep-strain rate due to reduced thickness-to-width ratio is in a good qualitative correlation with experimental results for Corresponding geometries. The constraint due to friction and interaction with the material outside the loaded surface area were identified as the cause for high apparent stiffness, which converges with decreasing thickness to an asymptotic value dependent on the modulus and I Poisson's ratio of the material.

  • 12.
    Ståhlberg, Daniel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nordin, Lars-Olof
    Varna, Janis
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Mechanical response of thermoset polymers under high compressive loads, 12005In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 290, p. 1063-1072Article in journal (Refereed)
    Abstract [en]

    The present Study describes the mechanical response of thermoset polymers under high compressive loads. A well-defined free radically cured vinyl ester resin has been used and studied in six different geometries in order to determine the dependence of apparent mechanical properties on the particular size and shape of a sample. The mechanical response in compression has also been compared to the response in tensile tests. Variation of the film thickness, boundary conditions and loading conditions reveal that there is a significant effect on the mechanical performance (apparent properties) of the polymer. When the thickness-to-width ratio of the sample is reduced in a compression test, the friction between the sample and the compression plates proves to be I of great importance. The yield stress increases dramatically when the thickness of the sample is reduced, whereas it decreases when the friction between sample and the compression plate is reduced. The creep decreases when the thickness of the material is reduced and it decreases even more due to reaction of the material surrounding the compressed part of I! the sample. The described test conditions and observed I phenomena will be subject to simulation in Part 2 of this study.

  • 13.
    Sun, Yang
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Waag, Thilo
    Xing, Zhe
    Yassin, Mohamed
    Yamamoto, Akihito
    Mustafa, Kamal
    Steinmüller-Nethl, Doris
    Krueger, Anke
    Albertsson, Ann-Chrisine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Reinforced Degradable Biocomposite by Homogenously Distributed Functionalized Nanodiamond Particles2015In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 300, no 4, p. 436-447Article in journal (Refereed)
    Abstract [en]

    Severe phase separation was observed in blending nanodiamond particle (n-DP) in poly (L-lactide-co-e-caprolactone) (poly(LLA-co-CL)) scaffold. In this study we optimized the scaffold by the addition of 1-50% (w/w) polylactide modified n-DP (n-DP-PLA) or benzoquinone-modified n-DP (n-DP-BQ). Composed by 10% n-DP-PLA, composite had 6 times higher E-modulus in tensile test, whereas the maximum reinforcement can be higher than 15 times. However, n-DP-BQ composites conserved the mechanical properties, and thermal properties of the polymer substrate. The attachment, spreading and growth of UE7T13 cells on modified n-DP composites were similar to poly(LLA-co-CL), and independent to n-DP concentrations. In summary, a proper modified n-DP is the key to reinforce poly(LLA-co-CL) for tissue engineering.

  • 14.
    Träger, Andrea
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Carlmark, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Interpenetrated Networks of Nanocellulose and Polyacrylamide with Excellent Mechanical and Absorptive Properties2018In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 303, no 5, article id 1700594Article in journal (Refereed)
    Abstract [en]

    Composites based on interpenetrating networks (IPNs) of cellulose nanofibril (CNF) aerogels and polyacrylamide are prepared and exhibit robust mechanical, water retaining, and re-swelling capacities. Furthermore, their swelling behavior is not affected by an increased ionic strength of the aqueous phase. These unprecedented IPNs combine the water retaining capacity of the polyacrylamide with the mechanical strength provided by the CNF aerogel template. The CNF aerogel/polyacrylamide composites exhibit a compressive stress at break greater than 250% compared with a neat polyacrylamide hydrogel. Furthermore, the composites retain their wet compression properties after drying and re-swelling, whereas the neat polyacrylamide hydrogels fail at a significantly lower stress and strain after drying and re-swelling. These composite materials highlight the potential of CNF aerogels to strengthen the mechanical properties and reduce the number of fracture defects during the drying and re-swelling of a hydrogel. These composites show the potential of being optimized for a plethora of applications, especially in the hygiene field and for biomedical devices.

  • 15.
    Vilaplana, Francisco
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Quality concepts for the improved use of recycled polymeric materials: A review2008In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 293, no 4, p. 274-297Article, review/survey (Refereed)
    Abstract [en]

    Polymeric waste materials should be considered resources for the manufacture of new products through recycling processes, with a similar status to virgin fossil-based plastics and biopolymers from renewable resources. Several efforts can be made to achieve this qualitative quantum leap in plastics recycling, and consequently introduce recycled products, with competitive performance, to the market. Scientific knowledge about the degradation processes during the life cycle and the development of fast and reliable analytical methods for the quality assessment of reccycled plastics are fundamental to guarantee their performance in new applications. Different strategies - restabilisation, rebuilding, compatibilisation, and addition of elastomers and fillers can be used to upgrade the structure and properties of polymeric waste streams. This review discusses recent developments in the mechanical recycling of plastics, focusing on how to produce quality materials from waste streams and, thus, contribute to a sustainable management of resources and energy.

  • 16.
    Zhang, Shi-Li
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Zou, Qichao
    Wu, Limin
    Preparation and characterization of polyurethane hybrids from reactive polyhedral oligomeric silsesquioxanes2006In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 291, no 7, p. 895-901Article in journal (Refereed)
    Abstract [en]

    Hybrid polyester resins containing polyhedral oligomeric silsesquioxanes (POSS), and their polyurethanes were prepared using reactive POSS as a substitution for partial diol monomer. They were investigated by FT-IR, rheometry, dynamic mechanical analysis, wide-angle X-ray diffraction contact-angle measurement, atomic force microscopy, and thermogravimetric analysis, respectively. The results showed that the hybrid polyester-POSS resins had a shear thinning behaviour and the more the POSS was embedded, the stronger the shear thinning behaviour, and the higher the viscosity. Incorporation of POSS could increase the glass transition temperature and thermal stability and decrease the surface free energy of the polyurethanes. When the POSS content was relatively high, the POSS molecules in hybrid polyurethane-POSS had a strong self-assembling ability to form nanocrystalline domains.

1 - 16 of 16
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