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1.	Oksman, Kristiina, et al. (author) Influence of thermoplastic elastomers on adhesion in polyethylene-wood flour composites 1998 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 68:11, s. 1845-1855 Journal article (peer-reviewed)abstract The mechanical properties of recycled low-density polyethylene/wood flour (LDPE/WF) composites are improved when a maleated triblock copolymer styrene-ethylene/butylene-styrene (SEBS-MA) is added as a compatibilizer. The composites' tensile strength reached a maximum level with 4 wt % SEBS-MA content. The compatibilizer had a positive effect on the impact strength and elongation at break but decreased the composites' stiffness. Dynamic mechanical thermal analysis (DMTA), a lap shear adhesion test, and a scanning electron microscope (SEM) were used to investigate the nature of the interfacial adhesion between the WF/SEBS and between the WF/ SEBS-MA. Tan δ peak temperatures for the various combinations showed interaction between the ethylene/butylene (EB) part of the copolymer and the wood flour in the maleated system. The shear lap test showed that adhesion between the wood and SEBS-MA is better than between the wood and SEBS. The electron microscopy study of the fracture surfaces confirmed good adhesion between the wood particles and the LDPE/SEBS-MA matrix. © 1998 John Wiley & Sons, Inc.
2.	Contat-Rodrigo, L., et al. (author) Ultrasonication and microwave assisted extraction of degradation products from degradable polyolefin blends aged in soil 2001 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 79:6, s. 1101-1112 Journal article (peer-reviewed)abstract 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.
3.	Karlsson, A., et al. (author) A new method for the determination of a hydrosilanization inhibitor applied to measurements during curing of a silicone elastomer 2001 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 79:13, s. 2349-2353 Journal article (peer-reviewed)abstract 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.
4.	Khabbaz, F., et al. (author) Py-GC/MS an effective technique to characterizing of degradation mechanism of poly (L-lactide) in the different environment 2000 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 78:13, s. 2369-2378 Journal article (peer-reviewed)abstract 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.
5.	Khabbaz, F., et al. (author) Rapid test methods for analyzing degradable polyolefins with a pro-oxidant system 2001 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 79:12, s. 2309-2316 Journal article (peer-reviewed)abstract 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.
6.	Edlund, Ulrica, et al. (author) Copolymerization and polymer blending of trimethylene carbonate and adipic anhydride for tailored drug delivery 1999 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 72:2, s. 227-239 Journal article (peer-reviewed)abstract 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.
7.	Gamstedt, E. Kristofer (author) Effects of debonding and fiber strength distribution on fatigue-damage propagation in carbon fiber-reinforced epoxy 2000 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 76:4, s. 457-474 Journal article (peer-reviewed)abstract 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.
8.	Hakkarainen, Minna, et al. (author) Influence of low molecular weight lactic acid derivatives on degradability of polylactide 2000 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 76:2, s. 228-239 Journal article (peer-reviewed)abstract 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.
9.	Johansson, Mats K. G., et al. (author) Radiation curing of hyperbranched polyester resins 2000 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 75:5, s. 612-618 Journal article (peer-reviewed)abstract 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.
10.	Lindhagen, Johan, et al. (author) Microscopical damage mechanisms in glass fiber reinforced polypropylene 1998 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 69:7, s. 1319-1327 Journal article (peer-reviewed)abstract The damage mechanisms in two structurally different glass mat reinforced polypropylene materials were studied. In situ microscopy was applied during the tensile testing of thin notched sheets. Micrographs of the damage processes in the two materials are presented. The major points of damage initiation were transversely oriented fibers and fiber bundles. In the swirled mat material, cracks grew along the fiber bundles; crack formation and growth was relatively unaffected by macroscopical stress concentration. In the short fiber material, crack growth occurred at the notch. In both materials the maximum load was determined by the fibers oriented in the longitudinal direction. The different damage mechanisms were interpreted in terms of damage zone size
11.	Oksman, Kristiina, et al. (author) Mechanical properties and morphology of impact modified polypropylene-wood flour composites 1998 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 67:9, s. 1503-1513 Journal article (peer-reviewed)abstract The mechanical properties and morphology of polypropylene/wood flour (PP/WF) composites with different impact modifiers and maleated polypropylene (MAPP) as a compatibilizer have been studied. Two different ethylene/propylene/diene terpolymers (EPDM) and one maleated styrene-ethylene/butylene-styrene triblock copolymer (SEBS-MA) have been used as impact modifiers in the PP/WF systems. All three elastomers increased the impact strength of the PP/WF composites but the addition of maleated EPDM and SEBS gave the greatest improvements in impact strength. Addition of MAPP did not affect the impact properties of the composites but had a positive effect on the composite unnotched impact strength when used together with elastomers. Tensile tests showed that MAPP had a negative effect on the elongation at break and a positive effect on tensile strength. The impact modifiers were found to decrease the stiffness of the composites. Scanning electron microscopy showed that maleated EPDM and SEBS had a stronger affinity for the wood surfaces than did the unmodified EPDM. The maleated elastomers are, therefore, expected to form a flexible interphase around the wood particles giving the composites better impact strength. MAPP further enhanced adhesion between WF and impact-modified PP systems. EPDM and EPDM-MA rubber domains were homogeneously dispersed in the PP matrix, the diameter of domains being between 0.1-1 m.
12.	Oksman, Kristiina, et al. (author) The nature and location of SEBS-MA compatibilizer in polyethylene-wood flour composites 1998 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 69:1, s. 201-209 Journal article (peer-reviewed)abstract A maleic-anhydride-grafted styrene-ethylene - butylene-styrene (SEBS-MA) triblock copolymer has been used as a compatibilizer in low-density polyethylene-wood flour (LDPE-WF) composite system. The location of compatibilizer was studied using transmission electron microscopy (TEM). The unsaturated parts of the copolymer were stained with osmium tetraoxide (OsO4) to enhance contrast between the different phases. TEM micrographs indicated that part of the compatibilizer was located at the interface between the wood particles and PE matrix and that wood was also stained by the OsO4. The nature of the interface between the wood surface and the SEBS-MA was studied using Fourier transform infrared spectroscopy (FTIR). The results indicated that MA reacts with wood through esterification and hydrogen bonding and also possibly through interaction between the styrene and wood.
13.	Skrifvars, Mikael, et al. (author) Microscopy of the morphology in low styrene emission glass fiber/unsaturated polyester laminates 1999 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 71:10, s. 1555-1562 Journal article (peer-reviewed)abstract Low styrene emission (LSE) unsaturated polyester resins are of interest in the context of increasing environmental concerns in the society. LSE resins have been developed to decrease styrene emission during the processing of composites based on unsaturated polyesters. In this article we applied a microscopy methodology to study morphology effects in laminates based on LSE polyesters. The study connects to the longer term objective to improve the understanding of how additives reduce styrene emission without imparting delamination resistance in composite laminates based on LSE polyesters. The major morphology differences between laminates made from different polyesters are discussed, including birefringent layers present as an interphase between different layers
14.	Adekunle, Kayode, et al. (author) Biobased Composites Prepared by Compression Molding with a Novel Thermoset Resin from Soybean Oil and a Natural-Fiber Reinforcement 2010 In: Journal of Applied Polymer Science. - : John Wiley & Sons, Inc.. - 0021-8995 .- 1097-4628. ; 116:3, s. 1759-1765 Journal article (peer-reviewed)abstract Biobased composites were manufactured with a compression-molding technique. Novel thermoset resins from soybean oil were used as a matrix, and flax fibers were used as reinforcements. The air-laid fibers were stacked randomly, the woven fabrics were stacked crosswise (0/90 ), and impregnation was performed manually. The fiber/resin ratio was 60 : 40. The prepared biobased composites were characterized by impact and flexural testing. Scanning electron microscopy of knife-cut cross sections of the specimens was also done to investigate the fiber–matrix interface. Thermogravimetric analysis of the composites was carried out to provide indications of thermal stability. Three resins from soybean oil [methacrylated soybean oil, methacrylic anhydride modified soybean oil (MMSO), and acetic anhydride modified soybean oil] were used as matrices. The impact strength of the composites with MMSO resin reinforced with air-laid flax fibers was 24 kJ/m2, whereas that of the MMSO resin reinforced with woven flax fabric was between 24 and 29 kJ/m2. The flexural strength of the MMSO resin reinforced with air-laid flax fibers was between 83 and 118 MPa, and the flexural modulus was between 4 and 6 GPa, whereas the flexural strength of the MMSO resin reinforced with woven fabric was between 90 and 110 MPa, and the flexural modulus was between 4.87 and 6.1 GPa.
15.	Adekunle, Kayode, et al. (author) Mechanical and Viscoelastic Properties of Soybean Oil Thermoset Reinforced with Jute Fabrics and Carded Lyocell Fiber 2011 In: Journal of Applied Polymer Science. - : John Wiley & Sons, Inc.. - 0021-8995 .- 1097-4628. ; 122:5, s. 2855-2863 Journal article (peer-reviewed)abstract Composites and hybrid composites were manufactured from renewable materials based on jute fibers, regenerated cellulose fibers (Lyocell), and thermosetting polymer from soybean oil. Three different types of jute fabrics with biaxial weave architecture but different surface weights, and carded Lyocell fiber were used as reinforcements. Hybrid composites were also manufactured by combining the jute reinforcements with the Lyocell. The Lyocell composite was found to have better mechanical properties than other composites. It has tensile strength and modulus of about 144 MPa and 18 GPa, respectively. The jute composites also have relatively good mechanical properties, as their tensile strengths and moduli were found to be between 65 and 84 MPa, and between 14 and 19 GPa, respectively. The Lyocell-reinforced composite showed the highest flexural strength and modulus, of about 217 MPa and 13 GPa, respectively. In all cases, the hybrid composites in this study showed improved mechanical properties but lower storage modulus. The Lyocell fiber gave the highest impact strength of about 35 kJ/m2, which could be a result of its morphology. Dynamic mechanical analysis showed that the Lyocell reinforced composite has the best viscoelastic properties.
16.	Adekunle, Kayode, 1970, et al. (author) Mechanical properties of natural fiber hybrid composites based on renewable thermoset resins derived from soybean oil, for use in technical applications 2012 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 124:6, s. 4530-4541 Journal article (peer-reviewed)abstract Natural fiber composites are known to have lower mechanical properties than glass or carbon fiber reinforced composites. The hybrid natural fiber composites prepared in this study have relatively good mechanical properties. Different combinations of woven and non-woven flax fibers were used. The stacking sequence of the fibers was in different orientations, such as 0 degrees, +45 degrees, and 90 degrees. The composites manufactured had good mechanical properties. A tensile strength of about 119 MPa and Young's modulus of about 14 GPa was achieved, with flexural strength and modulus of about 201 MPa and 24 GPa, respectively. For the purposes of comparison, composites were made with a combination of woven fabrics and glass fibers. One ply of a glass fiber mat was sandwiched in the mid-plane and this increased the tensile strength considerably to 168 MPa. Dynamic mechanical analysis was performed in order to determine the storage and loss modulus and the glass transition temperature of the composites. Microstructural analysis was done with scanning electron microscopy.
17.	Adekunle, Kayode, et al. (author) Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites 2009 In: Journal of Applied Polymer Science. - : John Wiley & Sons Inc.. - 0021-8995 .- 1097-4628. ; 115:6, s. 3137-3145 Journal article (peer-reviewed)abstract Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H-NMR, and 13C-NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross-linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H-NMR. The 13C-NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process.
18.	Adhikari, Arindam, et al. (author) Dopant induced effect on electrocatalytic reduction of nitrobenzene using conducting polypyrrole thin film electrodes 2011 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 120:2, s. 719-724 Journal article (peer-reviewed)abstract Conducting polypyrrole electrodes were prepared by electrochemical polymerization of pyrrole on vacuum-metallized glass substrates. These electrodes were modified by doping with a range of metal halides as dopant ions having different electronegativity. Electrochemical reduction of nitrobenzene using these electrodes was studied by means of cyclic voltammetry technique in acetonitrile medium containing aqueous HClO4 (0.1M) as supporting electrolyte. It was found that the electronegativity of the dopant ion played a very important role in the electrocatalytic activity. Polypyrrole doped with nickel chloride gave the highest anodic current at the reduction potential of nitrobenzene. The results were explained on the basis of charge transfer efficiency at the electrode-electrolyte interface, which was associated with the acceptor state created by the dopant in the semi-conducting polymer.
19.	Ahlinder, Astrid, et al. (author) Nondegradative additive manufacturing of medical grade copolyesters of high molecular weight and with varied elastic response 2020 In: Journal of Applied Polymer Science. - : WILEY. - 0021-8995 .- 1097-4628. ; 137:15 Journal article (peer-reviewed)abstract Although additive manufacturing through melt extrusion has become increasingly popular as a route to design scaffolds with complex geometries the technique if often limited by the reduction in molecular weight and the viscoelastic response when degradable aliphatic polyesters of high molecular weight are used. Here we use a melt extruder and fused filament fabrication printer to produce a reliable nondegradative route for scaffold fabrication of medical grade copolymers of L-lactide, poly(epsilon-caprolactone-co-L-lactide), and poly(L-lactide-co-trimethylene carbonate). We show that degradation is avoided using filament extrusion and fused filament fabrication if the process parameters are deliberately chosen based upon the rheological behavior, mechanical properties, and polymer composition. Structural, mechanical, and thermal properties were assessed throughout the process to obtain comprehension of the relationship between the rheological properties and the behavior of the medical grade copolymers in the extruder and printer. Scaffolds with a controlled architecture were achieved using high-molecular-weight polyesters exhibiting a large range in the elastic response causing negligible degradation of the polymers.
20.	Al-Maqdasi, Zainab, 1986-, et al. (author) Time-dependent properties of graphene nanoplatelets reinforced high-density polyethylene 2021 In: Journal of Applied Polymer Science. - : John Wiley and Sons Inc. - 0021-8995 .- 1097-4628. ; 138:30 Journal article (peer-reviewed)abstract The deformation of polymers at constant applied stress is one of their major drawbacks, limiting their use in advanced applications. The study of this property using classical techniques requires extensive testing over long periods of time. It is well known that reinforced polymers show improved behavior over time compared to their neat counterparts. In this study, the effect of adding different amounts of graphene nanoplatelets (GNPs) on the time-dependent properties of high-density polyethylene (HDPE) is investigated using short-term creep tests and load/unload recovery tests. The results are discussed in terms of the test profile and the influence of loading history. Viscoplasticity/viscoelasticity analysis is performed using Zapas model and by comparing creep, creep compliance and pure viscoelasticity curves. The results show that the reinforcement of 15 wt% GNP have the most significant effect on the time-dependent behavior, reducing the strain by more than 50%. The creep compliance curves show that nano-reinforced HDPE behaves nonlinearly viscoelastically even at very low stresses. In addition to demonstrating the effect of nano-reinforcement, the discussion of the results concludes that the influence of loading history can be quite significant and should not be neglected in the design and evaluation of material behavior. © 2021 The Authors.
21.	Albertsson, A-C., et al. (author) Degradation of enhanced environmentally degradable polyethylene in biological aqueous media: mechanisms during the first stages 1994 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 51:6, s. 1097-1105 Journal article (peer-reviewed)
22.	Albertsson, Ann-Christine, et al. (author) Effect of processing additives on (bio)degradability of film-blown poly(ε-caprolactone) 1998 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 70:1, s. 61-74 Journal article (peer-reviewed)
23.	Albertsson, Ann-Christine, et al. (author) The three stages in the degradation of polymers- polyethylene as a model substance 1988 In: Journal of Applied Polymer Science. - 0021-8995 .- 1097-4628. ; 35, s. 1289-1302 Journal article (peer-reviewed)
24.	Alin, Jonas, et al. (author) Type of Polypropylene Material Significantly Influences the Migration of Antioxidants from Polymer Packaging to Food Simulants During Microwave Heating 2010 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 118:2, s. 1084-1093 Journal article (peer-reviewed)abstract 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
25.	Andersson, Anna, et al. (author) Evaluation and characterization of ammoniumpolyphosphate-pentaerythritol-based systems for intumescent coatings 2007 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 104:2, s. 748-753 Journal article (peer-reviewed)abstract Intumescent coatings are increasingly used as a method of passive fire protection on steel constructions. By forming a carbon network and releasing a blowing agent, the thin intumescent film swells 100-fold at elevated temperatures. The highly insulating foam effectively prevents the load bearing steel from reaching its critical temperature at which it looses its mechanical properties and collapses. The role of the carbon donor in intumescent coatings has been studied. Comparison in temperature development, foaming ratios, and rheological behavior has been performed between formulations containing pentaerythritol (penta), di-penta, and tri-penta. A simulated fire test, in which the temperature development during intumescence was studied, showed that the formulations containing penta were considerably more efficient in keeping a low temperature throughout the process. A more rapid temperature development was displayed when using di-penta and tripenta as the carbon donor. Rheometer tests indicate that penta formulations enter the inturnescent process at a lower temperature and stays in it for a longer time than di-penta and tri-penta formulations. Furthermore, the crossover temperature and maximum phase angle are shifted towards higher temperatures by replacing penta with di-penta and with tri-penta in the formulations, respectively.
26.	Andersson, Anna, et al. (author) Intumescent foams - A novel flame retardant system for flexible polyurethane foams 2008 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 109:4, s. 2269-2274 Journal article (peer-reviewed)abstract A combination of intumescent components was evaluated as a novel flame retardant system in a flexible polyurethane foam, and the incorporation of these components gave rise to a significant enhancement of the flame retardant properties of the foam. The heat release rate was lowered at an early stage as well as throughout the fire, the total heat production was decreased and the time to ignition was prolonged. Mechanical measurements of the foam revealed enhanced properties in terms of stiffness accompanied by a large decrease in elongation at break as compared with a reference foam. (c) 2008 Wiley Periodicals, Inc.
27.	Andersson, Anna, et al. (author) Shear Behavior of Flexible Polyurethane Foams Under Uniaxial Compression 2009 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 111:5, s. 2290-2298 Journal article (peer-reviewed)abstract The mechanisms behind the load building capabilities of a hyperbranched polymer (HBP) in polyurethane (PU) foams have been investigated, using microscopy techniques and mechanical analyses. By broadening the traditional uniaxial compression characterization of PU foams to include combined shear deformations and compression behavior, an apparent Poisson ratio of the foam could be obtained in situ. The Poisson ratio as function of uniaxial compression ratio of the foam was thus studied for foams filled with Styrene Acrylonitrile (SAN) and foams containing HBP. Generally a window of deformation ratios could be defined in which the Poisson ratio was negative. The width of this window varied systematically with the SAN loading, where an increase in SAN particle loading resulted in a broadening of the negative Poisson ratio window. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2290-2298, 2009
28.	Andersson, M, et al. (author) Acetylation of jute: Effects on strength, rot resistance, and hydrophobicity 1989 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 37:12, s. 3437-3447 Journal article (peer-reviewed)
29.	Andersson, Thorbjörn, et al. (author) Degradation of low density polyethylene during extrusion. : IV. Off-flavor compounds in extruded films of stabilized LDPE 2005 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 95:3, s. 583-595 Journal article (peer-reviewed)abstract This study was aimed at finding a correlation between the experienced off-flavor in packed foods and the presence of specific degradation products in LDPE pack-aging films. The possibility to trap degradation products by chemical reactions with scavengers, i.e., a zeolite additive or antioxidants, was investigated This would prevent degradation products from migrating to the polymer film surface and further into food in contact with the film. It was found that off-flavor noted in water packed in LDPE films depended on extrusion temperature and exposure time for the melt to oxygen, that is, the parameters that influence the contents of oxidation products that are able to migrate from the polymer film. It was also found that adsorption of oxidative degradation products in a zeolite additive or protection of LDPE by using antioxidants could prevent off-flavor in the packed product (water). However, the antioxidant should be selected with regard to extrusion temperature because thermal instability in the additive might jeopardize the intended effect. Multifunctional antioxidants seem to provide improved protection, the most effective one evaluated in this work being Irganox E201, i.e., vitamin E. Concentrations of oxidized degradation products are well correlated to the perceived off-flavor in the packed water. The highest correlation between off-flavor and oxidized components was found for ketones in the range of C 7 to C9 and aldehydes in the range of C6 to C9.
30.	Andersson, Thorbjörn, et al. (author) Degradation of low density polyethylene during extrusion : III. Volatile compounds in extruded films creating off-flavor 2005 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 95:4, s. 847-858 Journal article (peer-reviewed)abstract This study was aimed at finding a correlation between the experienced off-flavor in packaged foods and the presence of specific degradation products in PE packaging films. The possibility to trap degradation products by chemical reactions with scavengers, that is, zeolites and maleic anhydride grafted LLDPE, were investigated. This trapping would prevent the degradation products from migrating to the polymer film surface and further into food in contact with the film. This work concludes that off-flavor in water packed in LDPE-films depends on extrusion temperature and the content of oxidation products in the polymer film. At lower extrusion temperatures, reactive additives to the LDPE material could control the release of off-flavor giving compo nents. Adsorbents, such as zeolites, which are able to adsorb degradation products, are effective also at higher extrusion temperatures. The amount of oxidized degradation products in the films correlated well to the perceived off-flavor in the packed water. The presence of aldehydes and ketones have a clear impact on the off-flavor. The best correlation between off-flavor and oxidized components were found for C7-C9 ketones, and aldehydes in the range of C5 to C8.
31.	Andersson, T, et al. (author) Degradation of low density polyethylene during extrusion. I. Volatile compounds in smoke from extruded films 2002 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 86:7, s. 1580-1586 Journal article (peer-reviewed)abstract Many problems with odor and taste in food packaging can be traced to degradation of the packaging materials during processing. From this starting point, the degradation of polyethylene in a commercial extrusion coating process was studied by analyzing degradation products present in smoke sampled at the extruder die orifice. Two low-density polyethylenes, A and B, with similar melt flow indexes and densities and obtained from different producers, were investigated. A third polymer, C, consisting of recycled material B, was also investigated. More than 40 aliphatic aldehydes and ketones, together with 14 different carboxylic acids, were identified in the smoke. The highest concentration was found for acetaldehyde, regardless of polymer and processing conditions. Increasing the extrusion temperatures in the range 280-325 degreesC increased the amounts of the oxidized products in the smoke. The extruded film thickness, 12 and 25 mum, influenced the concentrations of degradation products, With the thicker film giving higher amounts of product. The recycled polymer C generally gave lower concentrations of degradation products compared with the virgin polymer B. Difference ill the product spectrum between the two virgin polymers may be related to differences in the manufacturing process, Many of the identified compounds have very characteristic taste and smell and are consequently of interest fron on odor and taste point of view in food packaging applications. (C) 2002 Wiley Periodicals, Inc.
32.	Andersson, T, et al. (author) Degradation of low-density polyethylene during extrusion. VI. Effects of oxygen content in air gap 2005 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 96:5, s. 1767-1775 Journal article (peer-reviewed)abstract In our previous papers polyethylene degradation during extrusion coating has been studied and the type of degradation products that are formed and from which step they originate have been discussed. A trained sensory panel has rated the off-flavor intensities in water samples that have been in contact with various extruded films. Encouraged by the results from these investigations and the documented synergism between aldehydes and ketones and aldehydes and carboxylic acids in off-flavor intensity, the present study was aimed at confirming the belief that the off-flavor depends on the presence of oxidative degradation products that have migrated from the film into the water. By decreasing the oxygen concentration in the atmosphere surrounding the extruded melt presence of the highly oxidized species (i.e., carbonyl compounds and carboxylic acids) would decrease and thus the off-flavor in the water should decline. From this study it could be concluded that the extrusion temperature and the oxygen content in the atmosphere nearest the molten film before quenching are the most important parameters for oxidative degradation and residence time in the air gap influence the amount of oxidative degradation products formed. Furthermore we concluded that the off-flavor intensity is strongly correlated to the surface oxidation index of the film. Carboxylic acids are present in the water extracts of extruded films and are related to the off-flavor intensities. (c) 2005 Wiley Periodicals, Inc.
33.	Andersson, T, et al. (author) Degradation of polyethylene during extrusion. II. Degradation of low-density polyethylene, linear low-density polyethylene, and high-density polyethylene in film extrusion 2004 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 91:3, s. 1525-1537 Journal article (peer-reviewed)abstract The degradation of different polyethylenes-low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE)-with and without antioxidants and at different oxygen concentrations in the polymer granulates, have been studied in extrusion coating processing. The degradation was followed by online rheometry, size exclusion chromatography, surface oxidation index measurements, and gas chromatography-mass spectrometry. The degradations start in the extruder where primary radicals are formed, which are subject to the auto-oxidation when oxygen is present. In the extruder, crosslinking or chain scissions reactions are dominating at low and high melt temperatures, respectively, for LDPE, and chain scission is overall dominating for the more linear LLDPE and HDPE resins. Additives such as antioxidants react with primary radicals formed in the melt. Degradation taking place in the film between the die orifice, and the quenching point is mainly related to the exposure time to air oxygen. Melt temperatures above 280degreesC give a dominating surface oxidation, which increases with the exposure time to air between die orifice and quenching too. A number of degradation products were identified-for example, alclehydes and organic acids-which were present in homologous series. The total amount of aldehydes and acids for each number of chain carbon atoms were appeared in the order of C5>C4>C6>C7much greater thanC2 for LDPE, C5>C6>C4> C7much greater thanC2 for LLDPE, and C5>C6>C7>C4much greater thanC2 for HDPE. The total amounts of oxidized compounds presented in the films were related to the processing conditions. Polymer melts exposed to oxygen at the highest temperatures and longest times showed the presence dialdehydes, in addition to the aldehydes and acids. (C) 2003 Wiley Periodicals, Inc. J Appl Polyrn Sci 91: 1525-1537, 2004.
34.	Andersson, T, et al. (author) Degradation of polyethylene during extrusion. II. Degradation of low-density polyethylene, linear low-density polyethylene, and high-density polyethylene in film extrusion (vol 91, pg 1525, 2004) 2004 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 92:1, s. 684-685 Journal article (peer-reviewed)
35.	Ara, Behisht, et al. (author) Preparation and characterization of uniform molecularly imprinted polymer beads for separation of triazine herbicides 2012 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 126:1, s. 315-321 Journal article (peer-reviewed)abstract Uniform molecularly imprinted polymer beads were synthesized by precipitation polymerization for separation of triazine herbicides. A series of imprinted polymers were prepared using ametryn as template and divinylbenzene as crosslinking monomer, in combination with three different functional monomers under different solvent conditions. Under optimized reaction conditions, we obtained uniform molecularly imprinted polymer microspheres that display favorable molecular binding selectivity for triazine herbicides. The imprinted polymer beads synthesized using methacrylic acid as functional monomer in a mixture of methyl ethyl ketone and heptane showed the best results in terms of particle size distribution and molecular selectivity. Compared with nonimprinted polymer microspheres, the imprinted microspheres displayed significantly higher binding for a group of triazine herbicides including atrazine, simazine, propazine, ametryn, prometryn, and terbutryn. For the first time, precipitation polymerization has been used to produce highly uniform imprinted microspheres suitable for affinity separation of triazine herbicides. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
36.	Arias, Veluska, et al. (author) Polylactides with "green" plasticizers : Influence of isomer composition 2013 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 130:4, s. 2962-2970 Journal article (peer-reviewed)abstract 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.
37.	Arino Marine, Ruth, 1980, et al. (author) Enhancing the electrical conductivity of carbon black/graphite nanoplatelets: Poly(ethylene-butyl acrylate) composites by melt extrusion 2016 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 133:3 Journal article (peer-reviewed)abstract The influence of processing parameters such as screw geometry, temperature profile, and screw speed on the electrical properties of hybrid composites consisting of graphite nanoplatelets and carbon black in ethyl butyl acrylate was studied. Two different screws were used to compound the hybrid composites at two different temperatures and two different screw speeds. A beneficial effect was noted with regard to the electrical properties when adding nanoplatelets to the filler system. The cause could be a synergistic effect due to the difference in particle shape of the two fillers. Lower percolation thresholds were obtained with the conventional screw due to less breakage of the graphite nanoplatelets compared to the barrier screw. No significant changes of the electrical properties were observed when changing the temperature profiles or the screw speeds. Furthermore, the melt viscosity of the compounds was not appreciably affected at the rather low filler contents used here.
38.	Ayalew, Bahiru Tsegaye, 1986, et al. (author) Thermal and rheological properties and processability of thermoplastic lignocellulose 2024 In: Journal of Applied Polymer Science. - 1097-4628 .- 0021-8995. ; In Press Journal article (peer-reviewed)abstract Fossil-free biobased materials like thermoplastic lignocellulose are gaining attention because of climate issues. However, there is a challenge to make these as thermoplastic as commonly used thermoplastics. Arboform® is one of today's commercially available thermoplastic lignocellulose materials. In this work, the processability of this material was studied in detail and the effects of plasticizers on its processability, rheological, and mechanical properties were determined. Thermal/calorimetry analysis indicated that the processing temperature window was shifted to lower temperature with the use of tributyl citrate (TBC) and poly(ethylene glycol) (PEG 400) plasticizers, thus enabling extrusion at lower temperature. TBC and PEG 400 decreased both the glass transition temperature and melting point of the polylactide component. Surprisingly, they also affected the lignin component, as observed by the decreasing lignin decomposition temperature. It is observed that TBC and PEG400 lowered the stiffness of the compression molded material in the temperature range investigated (−30–180°C), and tensile tests in the presence of TBC revealed a decrease in ductility. Notable is that, in contrast to most thermoplastics, the Arboform® melt increases in viscosity and elastic moduli when the processing temperature was increased (from 180 to 200°C) or when processing time was increased.
39.	Ayyachi, Thayanithi, et al. (author) Defining the role of linoleic acid in acrylic bone cement 2022 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 139:25 Journal article (peer-reviewed)abstract Polymethylmethacrylate is clinically used as a bone cement in various orthopedic and trauma surgeries. Post the surgery, such conventional acrylic bone cement has been reported to cause adjacent vertebral fractures; modifying it by adding linoleic acid in the formulation has shown potential in averting such fractures thanks to bone-compliant mechanical properties, besides providing convenient handling properties. Although the resulting properties are attractive, the understanding of how linoleic acid imparts such advantageous properties remain unclear. Linoleic acid is typically sterilized in an autoclave before being used in the bone cement formulation; however, there are apprehensions whether the sterilization causes degradation. In this research, sterilized and unsterilized linoleic acid were evaluated alone and with different components of bone cement, such as activator, initiator, monomer, and inhibitor, and the ensuing structural changes in linoleic acid were monitored through 1H NMR and UV–Vis. The results reveal that linoleic acid degrade due to sterilization. In addition, evidence for reactions of sterilized/unsterilized linoleic acid with activator and initiator have been collected. We hypothesize that these reactions can reduce the availability of the components for the in situ polymerization of methyl methacrylate monomer and cause the improvement in handling properties and decrease in mechanical properties.
40.	Aziz, Shazed, et al. (author) Thermomechanical effects in the torsional actuation of twisted nylon 6 fiber 2017 In: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 134:47 Journal article (peer-reviewed)abstract Thermally induced torsional and tensile actuators based on twisted polymeric fibers have opened new opportunities for the application of artificial muscles. These newly developed actuators show significant torsional deformations when subjected to temperature changes, and this torsional actuation is the defining mechanism for tensile actuation of twisted and coiled fibers. To date it has been found that these actuators require multiple heat/cool cycles (referred to as “training” cycles) prior to obtaining a fully reversible actuation response. Herein, the effect of annealing conditions applied to twisted nylon 6 monofilament is investigated and it is shown that annealing at 200 °C eliminates the need for the training cycles. Furthermore, the effect of an applied external torque on the torsional actuation is also investigated and torsional creep is shown to be affected by the temperature and load
41.	Babu, NB Karthik, et al. (author) Self‐reinforced polymer composites: An opportunity to recycle plastic wastes and their future trends 2022 In: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 139:46 Research review (peer-reviewed)abstract Polymers and their composites have played an important role in industrial development. Polymer composites are becoming much stronger and more competitive than other materials as a result of ongoing research and development. This was made possible by newly developed techniques that could alter the physical and chemical properties of constituents. One of them is the self-reinforcement technique, which allows for the fabrication of high-strength thermoplastic polymer composites with reserved degradability, which is not possible with glass fiber/carbon fiber reinforcement. A self-reinforced polymer composite is made of a single polymeric material, which serves as both the matrix and the reinforcement. This review article discusses the use of self-reinforcement in various polymers and its impact on mechanical, thermal, and fire properties. Furthermore, the effects of process parameters (such as temperature and time, an), reinforcement structure, and mechanical property variation on the structure of self-reinforced composites are reviewed and presented in detail. In addition, the effect of foreign filler addition (such as flame retardants, inorganic particles, natural fibers, etc.) on self-reinforced composites is highlighted. In the end, the need for future research and its scope is presented.
42.	Bachinger, Angelika, et al. (author) Systematic evaluation of bromine-free flame-retardant systems in acrylonitrile-butadiene-styrene 2022 In: Journal of Applied Polymer Science. - : John Wiley & Sons, Ltd. - 0021-8995 .- 1097-4628. ; 139:13 Journal article (peer-reviewed)abstract A systematic investigation of phosphorus-based flame-retardant (PFR) systems in acrylonitrile-butadiene-styrene (ABS) is presented. The effect of various PFRs, combinations thereof and influence of different synergists is studied in terms of fire and mechanical performance, as well as toxicity of resulting ABS. Sustainable flame-retardant systems with a promising effect on the fire-retardant properties of ABS are identified: A combination of aluminum diethylphosphinate and ammonium polyphosphate is shown to exhibit superior flame-retardant properties in ABS compared to other studied PFRs and PFR combinations. Among a variety of studied potential synergists for this system, a grade of expandable graphite with a high-initiation temperature and a molybdenum-based smoke suppressant show the most promising effect, leading to a significant reduction of the peak heat release rate as well as the smoke production rate. Compared to current state-of-the-art brominated flame-retardant for ABS, the identified flame-retardant systems reduce the maximum smoke production rate by 70% and the peak heat release rate by 40%. However, a significant reduction of the impact performance of the resulting ABS is identified, which requires further investigation.
43.	Backman, A.C., et al. (author) Interaction between wood and polyurethane-alkyd lacquer resulting in a decrease in the glass transition temperature 2002 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 85:2, s. 595-605 Journal article (peer-reviewed)abstract The long-term properties of paint and glue are of great interest to both manufacturers and users of these materials. If a good bond is achieved, the surface between the wood and the paint or glue will be less susceptible to degradation. Thus, the wood and polymer must be compatible and develop some kind of bonding force between them. A high degree of interaction between wood and commercial polyurethane-alkyd lacquer was shown as a decrease by 10°C of the glass transition temperature (Tg) for the lacquer on wood compared to the pure lacquer. The lacquer also demonstrated good adhesion to wood at a microscale. The interaction was investigated with dynamic mechanical thermal analysis and scanning electron microscopy fractography. The reason for the decrease in Tg is probably because of the lacquer having a higher free volume when applied to the wood, most likely due to it being subjected to tensile forces developed during the drying of the lacquer. Results from investigations of wood impregnated with two different acrylates, a polymethylmethacrylate and a more hydrophilic acrylate, support the suggestion that a decrease in Tg will occur if the polymer adheres to wood, but that poor interaction with little or no adhesion will result in no decrease in Tg. This article also presents results of the dynamic mechanical behavior of Scots Pine in the tangential direction
44.	Backman, A.C., et al. (author) Interaction between wood and polyvinyl acetate glue studied with dynamic mechanical analysis and scanning electron microscopy 2004 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 91:5, s. 3009-3015 Journal article (peer-reviewed)abstract The long-term properties of bonds are those that are of special interest. To achieve good bonds, the wood polymers and the adhering polymers must be compatible. This paper describes studies of the interaction of wood (Pinus sylvestris) with commercial polyvinyl acetate (PVAc) glue, polymethylmethacrylate (PMMA), and a more hydrophilic acrylate. Interaction was studied with a dynamic mechanical thermal analyzer (DMTA) operating in tensile mode in the tangential direction of wood. DMTA results were correlated with scanning electron microscopy (SEM) fractography studies of adhesion between polymers and wood on a cell wall level. The hypothesis put forward is that a good adhesion on the cell wall level results in a decrease in the glass transition temperature (Tg) measured with DMTA. A decrease in Tg for the hydrophilic acrylate was shown when it was impregnated in wood. The decrease of Tg was correlated with good adhesion to wood on the cell wall level. For PVAc and PMMA no decrease in Tg was measured when glued or impregnated in wood. SEM study also showed that the adhesion on a cell wall level was poor. The results show that DMTA can be a useful technique to study adhesion between wood and glue on a molecular level.
45.	Badria, Adel, et al. (author) Acrylate-free tough 3D printable thiol-ene thermosets and composites for biomedical applications 2022 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 139:43 Journal article (peer-reviewed)abstract Polymer thermosets and composites based on rigid trizaine-trione (TATO) alkene and thiol monomers show great promise as bone fixation materials and dental composites due to their ability to efficiently crosslink via thiol-ene coupling chemistry into stiff and strong materials. In order to broaden the scope of these materials, a TATO thermoset was optimized for sterolithography (SLA) 3D printing through the addition of either a diluent (PETMP) and photo-absorber (Sudan I), or the addition of a free radical inhibitor (pyrogallol). A 3D printable hydroxyapatite (HA) composite was also formulated by adding a combination of nano-HA and micro-HA particles, which were found to increase the thermal stability and modulus of the material, respectively. The modulus of the printed thermosets containing Sudan I and pyrogallol exceeded any previously published acrylate-free thiol-ene SLA resins, at 1.6 (0.1) and 1.85 (0.06) GPa, respectively. The printed HA composite formulation had a modulus of 2.4 (0.2) GPa. All three formulations showed a comparable resolution to a commercially available SLA resin and were non-toxic toward Raw 264.7 and human dermal fibroblast cells. These results demonstrate the potential of TATO based SLA resins for the construction of strong, fully-customizable, printed implants for biomedical applications.
46.	Bakare, Fatimat Oluwatoyin, et al. (author) Synthesis and Characterization of Bio-Based Thermosetting Resins from Lactic Acid and Glycerol 2014 In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 131:12, s. 1-9 Journal article (peer-reviewed)abstract A bio-based thermoset resin has been synthesized from glycerol reacted with lactic acid oligomers of three different chain lengths: n=3, 7 and 10. Lactic acid was first reacted with glycerol by direct condensation and the resulted branched molecule was then end-functionalized with methacrylic anhydride. The resins were characterized using FTIR, 13C-NMR spectroscopy to confirm the resins chemical structure and by DSC and DMTA to obtain the thermal properties. The resin flow viscosities were also measured using a Rheometer with different stress levels for each temperature used, as this is an important characteristic for resins which are intended to be used as a matrix in composite applications. The results showed that the resin with chain length n=3 have a better mechanical, thermal and rheological properties than resin with n=7 and 10. Also with its biobased content of 78% and glass transition temperature at 97°C makes it comparable with the commercial unsaturated polyester resins.
47.	Bashir, Tariq, et al. (author) Electrical Resistance Measurement Methods and Electrical Characterization of Poly(3,4-ethylenedioxythiophene)- Coated Conductive Fibers 2012 In: Journal of Applied Polymer Science. - : John Wiley & Sons, Inc.. - 0021-8995 .- 1097-4628. ; 124:4, s. 2954-2961 Journal article (peer-reviewed)abstract Textile fibers and yarns of high conductivity, and their integration into wearable textiles for different electronic applications, have become an important research field for many research groups throughout the world. We have produced novel electrically conductive textile yarns by vapor-phase polymerization (VPP) of a conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), on the surface of commercially available textile yarns (viscose). In this article, we have presented a novel setup for electrical resistance measurements, which can be used not only for fibrous structures but also for woven structures of specific dimensions. We have reported a two-point resistance- measuring method using an already manufactured setup and also a comparison with the conventionally used method (so-called crocodile clip method). We found that the electrical properties of PEDOT-coated viscose fibers strongly depend on the concentration of oxidant (FeCl3)and the doping (oxidation) process of PEDOT. To evaluate the results, we used mass specific resistance values of PEDOT-coated viscose yarns instead of normal surface resistance values. The voltage–current (V–I) characteristics support the ohmic behavior of coated fibers to some extent. Monitoring of the charging effect of the flow of current through conductive fibers for prolonged periods of time showed that conductivity remains constant. The change in electrical resistance values with increase in the length of coated fibers was also reported. The resistance measuring setup employed could also be used for continuous measurement of resistance in the production of conductive fibers, as well as for four-point resistance measurement.
48.	Bengtsson, Jenny, et al. (author) Identifying breach mechanism during air-gap spinning of lignin–cellulose ionic-liquid solutions 2019 In: Journal of Applied Polymer Science. - : John Wiley and Sons Inc.. - 0021-8995 .- 1097-4628. Journal article (peer-reviewed)abstract To be able to produce highly oriented and strong fibers from polymer solutions, a high elongational rate during the fiber-forming process is necessary. In the air-gap spinning process, a high elongational rate is realized by employing a high draw ratio, the ratio between take-up and extrusion velocity. Air-gap spinning of lignin–cellulose ionic-liquid solutions renders fibers that are promising to use as carbon fiber precursors. To further improve their mechanical properties, the polymer orientation should be maximized. However, achieving high draw ratios is limited by spinning instabilities that occur at high elongational rates. The aim of this experimental study is to understand the link between solution properties and the critical draw ratio during air-gap spinning. A maximum critical draw ratio with respect to temperature is found. Two mechanisms that limit the critical draw ratio are proposed, cohesive breach and draw resonance, the latter identified from high-speed videos. The two mechanisms clearly correlate with different temperature regions. The results from this work are not only of value for future work within the studied system but also for the design of air-gap spinning processes in general.
49.	Bengtsson, Jenny, et al. (author) The challenge of predicting spinnability : Investigating benefits of adding lignin to cellulose solutions in air-gap spinning 2021 In: Journal of Applied Polymer Science. - : John Wiley and Sons Inc. - 0021-8995 .- 1097-4628. ; 138:26 Journal article (peer-reviewed)abstract In this study, the underlying mechanism for improved spinnability when mixing lignin and cellulose in solution was investigated. Co-processing of lignin and cellulose has previously been identified as a potential route for production of inexpensive and bio-based carbon fibers. The molecular order of cellulose contributes to the strength of the fibers and the high carbon content of lignin improves the yield during conversion to carbon fibers. The current work presents an additional benefit of combining lignin and cellulose; solutions that contain both lignin and cellulose could be air-gap spun at substantially higher draw ratios than pure cellulose solutions, that is, lignin improved the spinnability. Fibers were spun from solutions containing different ratios of lignin, from 0 to 70 wt%, and the critical draw ratio was determined at various temperatures of solution. The observations were followed by characterization of the solutions with shear and elongational viscosity and surface tension, but none of these methods could explain the beneficial effect of lignin on the spinnability. However, by measuring the take-up force it was found that lignin seems to stabilize against diameter fluctuations during spinning, and plausible explanations are discussed
50.	Bergman, Gunnar, et al. (author) Antiplasticization and transition to marked nonlinear viscoelasticity in poly(vinyl chloride)/acrylonitrile–butadiene copolymer blends 1977 In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 21:11, s. 2953-2961 Journal article (peer-reviewed)abstract A series of PVC/NBR blends with varying acrylonitrile (AN) content in the NBR has been studied in uniaxial tension creep tests. The tests have been carried out at 21.5 ± 0.5°C covering creep times from 10 to 1000 sec. NBR with low AN content, having poor compatibility with PVC, gives the blends with higher compliance and increased time dependence of the compliance. A higher AN content in the NBR gives the blends with the opposite properties when the NBR is added in small amounts. NBR with 40 wt‐% AN is found to act as an antiplasticizer giving minimal creep compliance when 7 wt‐% NBR is added. The antiplasticization reveals a considerably increased stress level at which the transition from approximatively linear to marked nonlinear viscoelasticity occurs and a decreased stress dependence of the creep compliance in the nonlinear viscoelastic range. Since the antiplasticization is also associated with a suppression of the β‐transition mechanism, the results provide a demonstration of the importance of β‐mechanism in the stress activated processes responsible for the appearance of nonlinear viscoelasticity in solid polymers.

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