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1.	Glauser, T., et al. (författare) Toughening of electron-beam cured acrylate resins 2000 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 280:08-jul, s. 20-25 Tidskriftsartikel (refereegranskat)abstract 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.
2.	Liu, X. H., et al. (författare) Investigation on unusual crystallization behavior in polyamide 6/montmorillonite nanocomposites 2002 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 287:8, s. 515-522 Tidskriftsartikel (refereegranskat)abstract 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.
3.	Liu, Xiaohui, et al. (författare) Polyamide 66/clay nanocomposites via melt intercalation 2002 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 287:3, s. 180-186 Tidskriftsartikel (refereegranskat)abstract Polyamide 66/clay nanocomposites (PA66CN) were prepared via a melt compounding method using a new kind of organophilic clay, which was obtained through co-intercalation of epoxy resin and quaternary ammonium into Na-montmorillonite. The dispersion effect of silicate layers in the matrix was studied by means of XRD and TEM. The silicate layers were dispersed homogeneously and nearly exfoliated in the matrix as a result of the strong interaction between epoxy groups and PA66. The mechanical properties and heat distortion temperature (HDT) of PA66CN increased dramatically. The notched Izod impact strength of PA66CN was 50% higher than that of PA66 when the clay loading was 5 wt.-%. Even at 10 wt.-% clay content, the impact strength was still higher than that of PA66. The finely dispersed silicate layers and the strong interaction between silicate layers and the matrix reduced the water absorption, at 10 wt.-% clay content; PA66CN only absorbs 60% water compared with PA66. The addition of silicate layers changed the crystal structure in PA66CN
4.	Glauser, T., et al. (författare) A comparison of radiation and thermal curing of thick composites 2000 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 274:1, s. 25-30 Tidskriftsartikel (refereegranskat)abstract 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.
5.	Glauser, T., et al. (författare) Electron-beam curing of thick thermoset composites : Effect of temperature and fiber 2000 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 274:1, s. 20-24 Tidskriftsartikel (refereegranskat)abstract 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.
6.	Abelow, Alexis, et al. (författare) Electroresponsive Nanoporous Membranes by Coating Anodized Alumina with Poly(3,4-ethylenedioxythiophone) and Polypyrrole 2014 Ingår i: Macromolecular materials and engineering. - : Wiley-VCH Verlagsgesellschaft. - 1438-7492 .- 1439-2054. ; 299:2, s. 190-197 Tidskriftsartikel (refereegranskat)abstract Electrically-active nanoporous membranes are prepared by coating the surface of anodized alumina with electroactive polymers using vapor phase polymerization with four combinations of conjugated polymers and doping ions: poly(3,4-ethylenedioxythiophone) and polypyrrole, FeCl3 and FeTs3. The permeability of the polymer-coated membranes is measured as a function of the applied electric potential. A reversible three-fold increase is found in molecular flux of a neutral dye for membranes in oxidized state compared to that in the reduced state. After analyzing various factors that may affect the molecular transport through these membranes, it is concluded that the observed behavior results mostly from swelling/deswelling of the polymers and from the confinement of the polymers inside the nanopores.
7.	Achtel, Christian, et al. (författare) Surprising Insensitivity of Homogeneous Acetylation of Cellulose Dissolved in Triethyl(n-octyl)ammonium Chloride/Molecular Solvent on the Solvent Polarity 2018 Ingår i: Macromolecular materials and engineering. - : Wiley-VCH Verlag. - 1438-7492 .- 1439-2054. ; 303:5 Tidskriftsartikel (refereegranskat)abstract The homogeneous acetylation of microcrystalline cellulose (MCC) by acetyl chloride and acetic anhydride in triethyl(n-octyl)ammonium chloride (N2228Cl)/molecular solvents (MSs) is investigated. The reaction with both acylating agents shows the expected increase of the degree of substitution (DS) on reaction temperature and time. Under comparable reaction conditions, however, DS is surprisingly little dependent on the MS employed, although the MSs differ in empirical polarity by 7 kcal molâˆ’1 as calculated by use of solvatochromic probes. The empirical polarities of (MCC + N2228Cl + MS) differ only by 0.8 kcal molâˆ’1. The formation a polar electrolyte sheath around cellulose chains presumably contributes to this â€œleveling-offâ€ of the dependence DS on the polarity of the parent MS employed. N2228Cl recovery and recycling is feasible. Â© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
8.	Aziz, Shazed, et al. (författare) Artificial Muscles from Hybrid Carbon Nanotube-Polypyrrole-Coated Twisted and Coiled Yarns 2020 Ingår i: Macromolecular materials and engineering. - : WILEY-V C H VERLAG GMBH. - 1438-7492 .- 1439-2054. ; 305:11 Tidskriftsartikel (refereegranskat)abstract Electrochemically or electrothermally driven twisted/coiled carbon nanotube (CNT) yarn actuators are interesting artificial muscles for wearables as they can sustain high stress. However, due to high fabrication costs, these yarns have limited their application in smart textiles. An alternative approach is to use off-the-shelf yarns and coat them with conductive polymers that deliver high actuation properties. Here, novel hybrid textile yarns are demonstrated that combine CNT and an electroactive polypyrrole coating to provide both high strength and good actuation properties. CNT-coated polyester yarns are twisted and coiled and subjected to electrochemical coating of polypyrrole to obtain the hierarchical soft actuators. When twisted without coiling, the polypyrrole-coated yarns produce fully reversible 25 degrees mm(-1)rotation, 8.3x higher than the non-reversible rotation from twisted CNT-coated yarns in a three-electrode electrochemical system operated between +0.4 and -1.0 V (vs Ag/AgCl). The coiled yarns generate fully reversible 10 degrees mm(-1)rotation and 0.22% contraction strain, 2.75x higher than coiled CNT-coated yarns, when operated within the same potential window. The twisted and coiled yarns exhibit high tensile strength with excellent abrasion resistance in wet and dry shearing conditions that can match the requirements for using them as soft actuators in wearables and textile exoskeletons.
9.	Blomfeldt, Thomas O. J., et al. (författare) Novel Foams Based on Freeze-Dried Renewable Vital Wheat Gluten 2010 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 295:9, s. 796-801 Tidskriftsartikel (refereegranskat)abstract 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.
10.	Brooke, Robert, 1989-, et al. (författare) All-Printed Electrochromic Stickers 2023 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:9 Tidskriftsartikel (refereegranskat)abstract Displays are one of the most mature technologies in the field of printed electronics. Their ability to be manufactured in large quantities and at low cost has led to their recent uptake into the consumer market. Within this article this technology is extended to electrochromic display stickers. This is achieved using a recent reverse display architecture screen printed on textile and paper sticker substrates. The electrochromic stickers are comparable to plastic control substrates and show little performance difference even when adhered to curved surfaces. The electrochromic display technology is extended to sticker labels for authentication applications by patterning either the dielectric or the graphical layer. A proof-of-concept prototype emulating a wax seal on an envelope is presented to show that other colors can be implemented in this technology. © 2023 The Authors.
11.	Brooke, Robert, 1989-, et al. (författare) All-Printed Multilayers and Blends of Poly(dioxythiophene) Derivatives Patterned into Flexible Electrochromic Displays 2023 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:2 Tidskriftsartikel (refereegranskat)abstract Low-cost, flexible and thin display technology is becoming an interesting field of research as it can accompany the wide range of sensors being developed. Here, the synthesis of poly(dimethylpropylene-dioxythiophene) (PProDOT-Me2) by combining vapor phase polymerization and screen printing is presented. A multilayer architecture using poly(3,4-ethylenedioxythiophene) (PEDOT) and PProDOT-Me2 to allow for electrochromic switching of PProDOT-Me2, thereby eliminating the need for a supporting transparent conductive (metal oxide) layer is introduced. Furthermore, the technology is adapted to a blended architecture, which removes the additional processing steps and results in improved color contrast (∆E* > 25). This blend architecture is extended to other conductive polymers, such as PEDOT and polypyrrole (PPy), to highlight the ability of the technique to adjust the color of all-printed electrochromic displays. As a result, a green color is obtained when combining the blue and yellow states of PEDOT and PPy, respectively. This technology has the potential to pave the way for all-printed multicolored electrochromic displays for further utilization in printed electronic systems in various Internet of Things applications. © 2022 The Authors.
12.	Dutta, Sujan, et al. (författare) Textile Actuators Comprising Reduced Graphene Oxide as the Current Collector 2023 Ingår i: Macromolecular materials and engineering. - : WILEY-V C H VERLAG GMBH. - 1438-7492 .- 1439-2054. Tidskriftsartikel (refereegranskat)abstract Electronic textiles (E-textiles) are made using various materials including carbon nanotubes, graphene, and graphene oxide. Among the materials here, e-textiles are fabricated with reduced graphene oxide (rGO) coating on commercial textiles. rGO-based yarns are prepared for e-textiles by a simple dip coating method with subsequent non-toxic reduction. To enhance the conductivity, the rGO yarns are coated with poly(3,4-ethylene dioxythiophene): poly(styrenesulfonic acid) (PEDOT) followed by electrochemical polymerization of polypyrrole (PPy) as the electromechanically active layer, resulting in textile actuators. The rGO-based yarn actuators are characterized in terms of both isotonic displacement and isometric developed forces, as well as electron microscopy and resistance measurements. Furthermore, it is demonstrated that both viscose rotor spun (VR) and viscose multifilament (VM) yarns can be used for yarn actuators. The resulting VM-based yarn actuators exhibit high strain (0.58%) in NaDBS electrolytes. These conducting yarns can also be integrated into textiles and fabrics of various forms to create smart e-textiles and wearable devices.
13.	El Seoud, Omar, et al. (författare) Cellulose Regeneration and Chemical Recycling : Closing the “Cellulose Gap” Using Environmentally Benign Solvents 2020 Ingår i: Macromolecular materials and engineering. - : Wiley-VCH Verlag. - 1438-7492 .- 1439-2054. ; 305:4 Tidskriftsartikel (refereegranskat)abstract Strategies to mitigate the expected “cellulose gap” include increased use of wood cellulose, fabric reuse, and recycling. Ionic liquids (ILs) are employed for cellulose physical dissolution and shaping in different forms. This review focuses on the regeneration of dissolved cellulose as nanoparticles, membranes, nonwoven materials, and fibers. The solvents employed in these applications include ILs and alkali solutions without and with additives. Cellulose fibers obtained via the carbonate and carbamate processes are included. Chemical recycling (CR) of polycotton (cellulose plus poly(ethylene terephthalate)) is addressed because depending on the recycling approach employed, this process is akin to regeneration. The strategies investigated in CR include preferential dissolution or depolymerization of one component of the blend, and separation of both components using ILs. It is hoped that this review focuses the attention on the potential applications of regenerated cellulose from its solutions and contributes to the important environmental issue of recycling of used materials.
14.	Floris, Paolo Sebastiano, et al. (författare) Anisotropic Lattice Thermal Conductivity in Highly Ordered PEDOT Fibers 2024 Ingår i: Macromolecular materials and engineering. - : WILEY-V C H VERLAG GMBH. - 1438-7492 .- 1439-2054. Tidskriftsartikel (refereegranskat)abstract When it comes to sustainable and efficient energy solutions, organic semiconductors can play an important role in thermoelectric applications, since they are non-toxic, cheap, made of abundant chemical species, and show intrinsically low thermal conductivities. Their electrical conductivity can be optimized via doping. Yet, thermal conduction should be as low as possible and, to this end, the atomic scale mechanisms behind heat transport -e.g. the correlation between morphology and thermal conductivity or the role of doping- should be understood in detail. Fully atomistic molecular dynamics calculations of the lattice thermal conductivity of doped poly(3,4-ethylenedioxythiophene) (PEDOT) highly ordered, quasi-crystalline nanofibers are presented here. It is found that the conductivity along the backbone direction is not necessarily the highest, but it depends on the length of the PEDOT chains, thus the degree of anisotropy depends on the the aspect ratio of the nanofiber. Indeed, transport along the lamellar direction can be of the same order or higher than that of the backbone if their lengths are comparable. These results challenge the usual expectation that thermal conduction along the backbone largely exceeds those along the lamellar and pi - pi direction and have the important consequence that the anisotropy could be leveraged in thermal management applications. Lattice thermal conduction in highly ordered PEDOT fibers is anisotropic, but not as anisotropic as one may expect. Indeed, these results challenge the usual expectation that thermal conduction along the backbone largely exceeds those along the lamellar and pi-pi direction, showing that anisotropy can be tuned by controlling the nanofiber aspect ratio. image
15.	Gabrielsson, Erik, et al. (författare) Spatiotemporal Control of Amyloid-Like A Plaque Formation Using a Multichannel Organic Electronic Device 2016 Ingår i: Macromolecular materials and engineering. - : WILEY-V C H VERLAG GMBH. - 1438-7492 .- 1439-2054. ; 301:4, s. 359-363 Tidskriftsartikel (refereegranskat)abstract We herein report on an iontronic device to drive and control A1-40 and A1-42 fibril formation. This system allows kinetic control of A aggregation by regulation of H+ flows. The formed aggregates show both nanometer-sized fibril structure and microscopic growth, thus mimicking senile plaques, at the H+-outlet. Mechanistically we observed initial accumulation of A1-40 likely driven by electrophoretic migration which preceded nucleation of amyloid structures in the accumulated peptide cluster.
16.	Georgantopoulos, Christos K., et al. (författare) Derivation of a qualitative model for the spatial characteristic wavelength of extrusion flow instabilities: Investigation of a polybutadiene rubber through capillary, slit and complex geometry extrusion dies 2022 Ingår i: Macromolecular Materials and Engineering. - : Wiley. - 1439-2054 .- 1438-7492. Tidskriftsartikel (refereegranskat)abstract The extrusion flow instabilities of a commercial polybutadiene (PBD) are investigated as a function of different extrusion die geometries, such as round capillary, slit, and complex cross-section profile slit dies via capillary rheology. Qualitative models are used to fit the experimental data for the spatial characteristic wavelength (λ) of the appearing extrusion flow instabilities. A new qualitative model for the slit die geometry, rectangular cross-section, is derived based on the theoretical concept of the “two layers” extrudate and the force balance at the die exit region. The proposed qualitative model for the slit die geometry is used to predict the spatial characteristic wavelength (λ) for extrudates obtained by complex cross-section profile slit die geometries similar to industrial manufacturing. Correlation between the ratio of the extensional ( ) and shear ( ) stress at the die exit area and the characteristic dimension, height H for slit dies and diameter D for round capillary dies, is presented. Moreover, a geometry-dependent model is used to predict the spatial characteristic wavelength (λ) of the extrusion flow instabilities from a round capillary die to a slit die and vice versa.
17.	Georgantopoulos, Christos K., et al. (författare) Mechano‐Optical Characterization of Extrusion Flow Instabilities in Styrene‐Butadiene Rubbers: Investigating the Influence of Molecular Properties and Die Geometry 2021 Ingår i: Macromolecular Materials and Engineering. - : Wiley. - 1439-2054 .- 1438-7492. ; 306:5 Tidskriftsartikel (refereegranskat)abstract The extrusion flow instabilities of two commercial styrene-butadiene rubbers are investigated as they vary in isomer content (1,4-cis, 1,4-trans, and 1,2 con- formation) of the butadiene monomer and the molecular architecture (linear, branched). The investigated samples have similar multimodal molecular weight distribution. Two geometries of extrusion dies, slit and round capillary, are compared in terms of the type and the spatial characteristics of the flow instabilities. The latter are quantified using three methods: a highly pressure sensitive slit die, online and offline optical analysis. The highly pressure- sensitive slit die has three piezoelectric pressure transducers (Δt ≈ 10−3 s and Δp ≈ 10−5 bar) placed along the die length. The characteristic frequency (fChar.) of the flow instabilities follows a power law behavior as a function of shear rate to a 0.5 power for both materials, f Char. ∝ γ app.. A qualitative model is used to predict the spatial characteristic wavelength (λ) of the flow instabilities from round capillary to slit dies and vice versa. Slip velocities (Vs) are used to quantify the slippage at slit and round capillary dies as well.
18.	Haubold, Thorben, et al. (författare) How Phosphorous Flame Retardant Additives Affect Benzoxazine-Based Monomer and Polymer Properties 2023 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:11 Tidskriftsartikel (refereegranskat)abstract The phosphorous-based flame retardant additives poly(m-phenylene methylphosphonate) (PMP) and resorcinol bis(diphenyl phosphate) (RDP) are reacted with bisphenol F and aniline–based benzoxazine (BF-a). DSC, rheological analysis, FT-IR, and soxhlet extraction reveal the covalent incorporation of both FR additives—initiating phenols in PMP structure as well as free phenols generated via transesterification reaction in the case of RDP. In contrast to PMP, RDP elongates the processing window but decreases the thermo–mechanical properties. Both additives increase the resistance in reactions against small flames with solely a phosphorous loading of 0.3 wt%, resulting in a V-0 rating and an improvement in the OI value by up to 2% for RDP and 4% for PMP. Both FRs reduce the heat release rate but increase the smoke production and the smoke toxicity in the case of RDP.
19.	Jedvert, Kerstin, et al. (författare) Adsorption Studies of Amino Cellulose on Cellulosics 2017 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 302:7 Tidskriftsartikel (refereegranskat)abstract Adsorption of a typical example of a new class of amino cellulose, namely 6-deoxy-6-(2-aminoethyl)amino cellulose at different pH-values and in the presence of electrolytes, onto cellulose model substrates is studied with surface plasmon resonance and quartz crystal microbalance with dissipation monitoring. Unexpectedly, adsorption is consistently higher at a higher pH-value of 10, indicating that solubility and interactions between amine moieties and cellulose are more important than electrostatic interactions. The findings are highly relevant for the process to modify material surfaces with amino cellulose in water-based systems as a universal tool for changing the surface properties and chemistry. Potential applications for an antimicrobial all biobased material could be found, e.g., as medical textiles or in the biotechnology sector.
20.	Kaur, Rajdeep, et al. (författare) Ion Track Formation and Nanopore Etching in Polyimide : Possibilities in the MeV Ion Energy Regime 2023 Ingår i: Macromolecular materials and engineering. - : Wiley-VCH Verlagsgesellschaft. - 1438-7492 .- 1439-2054. Tidskriftsartikel (refereegranskat)abstract Polyimide films of thickness 7.5 µm are irradiated by a wide range of ions (1H to 197Au) with energies between 1.05 and 48 MeV. Irradiated samples are then chemically etched in sodium hypochlorite solution to investigate nanopore formation due to ion track etching. A threshold in terms of electronic stopping power, Set, needs to be surpassed to preferentially etch the ion tracks. Close to Set, intermittent tracks are formed where only part of the track is etchable. The fraction of these etchable parts increases as we move away from Set, toward higher stopping powers, eventually yielding continuous etchable tracks. Both intermittent and continuous track formation thresholds are observed to be velocity-dependent, yielding a decrease of the thresholds in the present work compared to previously reported thresholds for swift heavy ions. This finding leads the authors to suggest that electrostatic ion accelerators with terminal voltages of several MV are applicable for the production of ion track membranes up to ≈10–20 µm in thickness. Suitable ions for nanopores in 7.5 µm polyimide films include 42 MeV 59Co and 48 MeV 197Au. The growth mechanism for the pores during etching is discussed, relating it to the properties of the original ion track.
21.	Khosravi, Sara, et al. (författare) Wheat-gluten-based adhesives for particle boards : Effect of crosslinking agents 2014 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 299:1, s. 116-124 Tidskriftsartikel (refereegranskat)abstract 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.
22.	Kim, Youngseok, et al. (författare) Robust PEDOT:PSS Wet‐Spun Fibers for Thermoelectric Textiles 2020 Ingår i: Macromolecular Materials and Engineering. - : Wiley. - 1439-2054 .- 1438-7492. ; 305:3, s. 1900749- Tidskriftsartikel (refereegranskat)abstract To realize thermoelectric textiles that can convert body heat to electricity, fibers with excellent mechanical and thermoelectric properties are needed. Although poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is among the most promising organic thermoelectric materials, reports that explore its use for thermoelectric fibers are all but absent. Herein, the mechanical and thermoelectric properties of wet‐spun PEDOT:PSS fibers are reported, and their use in energy‐harvesting textiles is discussed. Wet‐spinning into sulfuric acid results in water‐stable semicrystalline fibers with a Young's modulus of up to 1.9 GPa, an electrical conductivity of 830 S cm−1, and a thermoelectric power factor of 30 μV m−1 K−2. Stretching beyond the yield point as well as repeated tensile deformation and bending leave the electrical properties of these fibers almost unaffected. The mechanical robustness/durability and excellent underwater stability of semicrystalline PEDOT:PSS fibers, combined with a promising thermoelectric performance, opens up their use in practical energy‐harvesting textiles, as illustrated by an embroidered thermoelectric fabric module.
23.	Krupicka, A., et al. (författare) Viscoelasticity in polymer films on rigid substrates 2003 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 288:2, s. 108-116 Tidskriftsartikel (refereegranskat)abstract 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.
24.	Lin, Xiang, et al. (författare) Ionic Conjugated Microporous Polymers for Cycloaddition of Carbon Dioxide to Epoxides 2024 Ingår i: Macromolecular materials and engineering. - 1438-7492 .- 1439-2054. ; 309:2 Tidskriftsartikel (refereegranskat)abstract Along the development of ionic porous organic polymers, simple and efficient synthetic methods are actively pursued. Herein, the Debus–Radziszewski reaction is applied to synthesize ionic conjugated microporous polymers (iCMPs) in one step. A series of imidazolium-linked iCMP-X (X = 1, 2, 3) are developed for CO2 sorption and in situ conversion with epoxide into cyclic carbonates. The as-synthesized iCMPs are characterized in detail by scanning electron microscope, solid-state nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction analysis, N2/CO2 sorption, and more. Among all synthesized iCMPs, iCMP-1 possesses the highest specific surface area and in turn the strongest CO2 sorption capacity. Moreover, through a simple anion ion exchange reaction with halide, iCMP-1 is transformed to iCMP-1@Cl that embodies significant catalytic capability for converting CO2 into cyclic carbonates.
25.	Liu, Sirui, et al. (författare) Design of Hygroscopic Bioplastic Products Stable in Varying Humidities 2023 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 308:2 Tidskriftsartikel (refereegranskat)abstract Hygroscopic biopolymers like proteins and polysaccharides suffer from humidity-dependent mechanical properties. Because humidity can vary significantly over the year, or even within a day, these polymers will not generally have stable properties during their lifetimes. On wheat gluten, a model highly hygroscopic biopolymer material, it is observed that larger/thicker samples can be significantly more mechanically stable than thinner samples. It is shown here that this is due to slow water diffusion, which, in turn, is due to the rigid polymer structure caused by the double-bond character of the peptide bond, the many bulky peptide side groups, and the hydrogen bond network. More than a year is required to reach complete moisture saturation (≈10 wt.%) in a 1 cm thick plate of glycerol-plasticized wheat gluten, whereas this process takes only one day for a 0.5 mm thick plate. The overall moisture uptake is also retarded by swelling-induced mechanical effects. Hence, hygroscopic biopolymers are better suited for larger/thicker products, where the moisture-induced changes in mechanical properties are smeared out over time, to the extent that the product remains sufficiently tough over climate changes, for example, throughout the course of a year.
26.	Meszynska, Anna, et al. (författare) Effect of Oligo-Hydroxyalkanoates on Poly(3-Hydroxybutyrate-co-4-Hydroxybutyrate)-Based Systems 2015 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 300:6, s. 661-666 Tidskriftsartikel (refereegranskat)abstract 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.
27.	Naue, Ingo F. C., et al. (författare) A new high sensitivity system to detect instabilities during the extrusion of polymer melts 2015 Ingår i: Macromolecular Materials and Engineering. - : Wiley. - 1439-2054 .- 1438-7492. ; 300:11, s. 1141-1152 Tidskriftsartikel (refereegranskat)abstract This publication is concerned with the development of a novel high sensitivity instability detection die for a laboratory size extruder. The high sensitivity detection system consists of piezoelectric transducers placed along the die length to monitor local pressure fluctuations, having temporal and pressure resolutions of up to ∆t ~ 10−3 s and ∆p ~ 10−5 bar, at a nominal pressure of 500 bar. The system is tested on short chain branched polyethylenes, namely on the detection and characterization of the sharkskin instability. It is shown that the determined instabilities are related to characteristic peaks in the corresponding in-situ pressure Fourier-transform spectra and that other peaks are caused by different, but defined, sources. The in situ results obtained are validated through optical image analysis of the instabilities. The implementation of high sensitivity detection systems on industrial processing equipment could lead to new methods for online process optimization, specifically maximum processing throughput at minimum energy consumption, and additionally in quality control.
28.	Noè, C., et al. (författare) Frontal-Photopolymerization of Fully Biobased Epoxy Composites 2022 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 307:6, s. 2100864- Tidskriftsartikel (refereegranskat)abstract The radical-induced cationic frontal photopolymerization (RICFP) of fully biobased epoxy composites is successfully demonstrated. This curing strategy considerably reduces the curing time and improves the efficiency of the composite fabrication. Two different natural fiber fabrics made of cellulose and flax fibers are embedded in two epoxy matrices, one derived from vanillin (diglycidylether of vanillyl alcohol-DGEVA) and the other from petroleum (3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate-CE). After RICFP the composites are characterized by means of dynamic mechanical thermal analysis and tensile tests. The mechanical properties improved with increasing fiber content, confirming a strong adhesion between the matrix and the reinforcing fiber fabrics, which is further evidenced by scanning electron microscopy analyses of the fracture surfaces. Furthermore, these fully bio-based composites possess comparable or even higher mechanical strength compared with the corresponding epoxy composites fabricated with conventional CE resin. A promising facile route to high-performing natural fiber-biobased epoxy resin composites is presented.
29.	Nordin, Lars-Olof, et al. (författare) Mechanical response of thermoset polymers under high compressive loads, 2 2005 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 290:11, s. 1073-1082 Tidskriftsartikel (refereegranskat)abstract 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 Poisson's ratio of the material.
30.	Pashazadehgaznagh, Sajjad, 1994, et al. (författare) An Intriguing Array of Extrudate Patterns in Long-Chain Branched Polymers During Extrusion 2023 Ingår i: Macromolecular Materials and Engineering. - 1439-2054 .- 1438-7492. ; 308:8 Tidskriftsartikel (refereegranskat)abstract The present study highlights a range of surface and volume extrudate patterns that can be detected during the extrusion flow of long-chain branched polymers. Thus, four linear low-density polyethylenes (LDPEs) have been extruded using a single-screw extruder coupled to an inline optical imaging system. The selected LDPEs are selected to outline the influence of molecular weight and long-chain branching on the types of melt flow extrusion instabilities (MFEI). Through the inline imaging system, space–time diagrams are constructed and analyzed via Fourier-transformation using a custom moving window procedure. Based on the number of characteristic frequencies, peak broadness, and whether they are surface or volume distortions, three main MFEI types, distinct from those typically observed in linear and short-chain branched polymers, are identified. The higher molecular weight, low long-chain branching LDPEs exhibited all three instability types, including a special type volume instability. Independently of the molecular weight, higher long-chain branching appeared to have a stabilizing effect on the transition sequences by suppressing volume extrudate distortions or limiting surface patters to a form of weak intensity type.
31.	Piskounova, Sonya, et al. (författare) The Effect of Mixing on the Mechanical Properties of Hyaluronan-Based Injectable Hydrogels 2011 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 296:10, s. 944-951 Tidskriftsartikel (refereegranskat)abstract A method for determining the correlation between the mixing of two reactive polymers and the structural and mechanical properties of the formed hydrogels is presented. Rheological measurements show that insufficient mixing gives rise to soft and not fully crosslinked hydrogels while excessive mixing beyond gel point results in weaker hydrogels due to potential breakage of their 3D network. Furthermore, the hydrogels swell significantly more in cell culture medium than in phosphate-buffered saline, attributed to interactions with additional molecules such as proteins. Thus, moderate mixing gives rise to the most homogenous and mechanically stable hydrogels and the choice of medium e.g., for release experiments, should be consistent in order to avoid unnecessary variations in the data caused by different swelling profiles.
32.	Raja, Pradeep, et al. (författare) A Review of Sustainable Bio-Based Insulation Materials for Energy-Efficient Buildings 2023 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:10 Forskningsöversikt (refereegranskat)abstract The surge towards a sustainable future in the construction industry requires the use of bio-based insulation materials as an alternative to conventional ones for improving energy efficiency in structures. In this article, the features of bio-based insulation materials, including their thermal conductivities, moisture buffering value, fire performance, and life cycle evaluations are examined. It is clear from the review that pre- and post-treatment of the bio-based materials used for insulation materials optimize their properties. The life cycle analysis reveals a significant reduction in global warming potential (GWP) compared to conventional foams. In addition, it is envisaged that producing bio-based insulation materials on a larger scale will further decrease the net GWP. The article, therefore, proposes the implementation of policies that will promote the commercialization of bio-based insulation materials.
33.	Sakai, Reika, et al. (författare) Fabrication of Polylactide-Based Biodegradable Thermoset Scaffolds for Tissue Engineering Applications 2013 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 298:1, s. 45-52 Tidskriftsartikel (refereegranskat)abstract 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.
34.	Schmid, Daniel, et al. (författare) Melt elongation of polymer nanocomposites : A method for the controlled production of dichroic films 2008 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 293:6, s. 471-478 Tidskriftsartikel (refereegranskat)abstract 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.
35.	Sensi, Matteo, et al. (författare) Monitoring DNA Hybridization with Organic Electrochemical Transistors Functionalized with Polydopamine 2022 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 307:5 Tidskriftsartikel (refereegranskat)abstract Organic electrochemical transistors (OECTs) are finding widespread application in biosensing, thanks to their high sensitivity, broad dynamic range, and low limit of detection. An OECT biosensor requires the immobilization of a biorecognition probe on the gate, or else on the channel, through several, often lengthy, chemical steps. In this work, a fast and straightforward way to functionalize the carbon gate of a fully screen-printed OECT by means of a polydopamine (PDA) film is presented. By chemical immobilization of an amine-terminated single-stranded oligonucleotide, containing the HSP70 promoter CCAAT sequence, on the PDA film, the detection of the complementary DNA strand is demonstrated. Furthermore, the specificity of the developed genosensor is assessed by comparing its response to the fully complementary strand with the one to partially complementary and noncomplementary oligonucleotides. The developed sensor shows a theoretical limit of detection (LOD) of 100 × 10−15 m and a dynamic range over four orders of magnitude. © 2022 The Authors.
36.	Ståhlberg, Daniel, et al. (författare) Mechanical response of thermoset polymers under high compressive loads, 1 2005 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 290, s. 1063-1072 Tidskriftsartikel (refereegranskat)abstract 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.
37.	Ståhlberg, Daniel, et al. (författare) Mechanical response of thermoset polymers under high compressive loads, 2 : Modeling 2005 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 290:11, s. 1073-1082 Tidskriftsartikel (refereegranskat)abstract 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.
38.	Sun, Yang, et al. (författare) Reinforced Degradable Biocomposite by Homogenously Distributed Functionalized Nanodiamond Particles 2015 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 300:4, s. 436-447 Tidskriftsartikel (refereegranskat)abstract 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.
39.	Träger, Andrea, et al. (författare) Interpenetrated Networks of Nanocellulose and Polyacrylamide with Excellent Mechanical and Absorptive Properties 2018 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 303:5 Tidskriftsartikel (refereegranskat)abstract 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.
40.	Ulmefors, Hanna, et al. (författare) Solution-Spinning of a Collection of Micro- and Nanocarrier-Functionalized Polysaccharide Fibers 2022 Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 307:8 Tidskriftsartikel (refereegranskat)abstract Continuous polysaccharide fibers and nonwovens—based on cellulose, hydroxypropyl cellulose, chitosan, or alginate—containing biopolymeric microcapsules (MC) or mesoporous silica nanoparticles (MSN) are prepared using a wet-spinning or solution blowing technique. The MCs are homogeneously distributed in the fiber matrices whereas the MSNs form discrete micron-sized aggregates as demonstrated using scanning electron-, fluorescence-, and confocal microscopy. By encapsulating the model compound pyrene, it is shown that 95% of the substance remains in the fiber during the formation process as compared to only 7% for the nonencapsulated substance. The material comprising the MC has a strong impact on the release behavior of the encapsulated pyrene as investigated using methanol extraction. MCs based on poly(l-lactic acid) prove to be practically impermeable with no pyrene released in contrast to MCs based on poly(lactic-co-glycolic acid) which allow for diffusion of pyrene through the MC and fiber as visualized using fluorescence microscopy. © 2022 The Authors.
41.	Vijaybabu, T. R., et al. (författare) High Thermal Conductivity Polymer Composites Fabrication through Conventional and 3D Printing Processes: State-of-the-Art and Future Trends 2023 Ingår i: Macromolecular materials and engineering. - : John Wiley & Sons. - 1438-7492 .- 1439-2054. ; 308:7 Forskningsöversikt (refereegranskat)abstract The lifespan and the performance of flexible electronic devices and components are affected by the large accumulation of heat, and this problem must be addressed by thermally conductive polymer composite films. Therefore, the need for the development of high thermal conductivity nanocomposites has a strong role in various applications. In this article, the effect of different particle reinforcements such as single and hybrid form, coated and uncoated particles, and chemically treated particles on the thermal conductivity of various polymers are reviewed and the mechanism behind the improvement of the required properties are discussed. Furthermore, the role of manufacturing processes such as injection molding, compression molding, and 3D printing techniques in the production of high thermal conductivity polymer composites is detailed. Finally, the potential for future research is discussed, which can help researchers to work on the thermal properties enhancement for polymeric materials.
42.	Vilaplana, Francisco, et al. (författare) Quality concepts for the improved use of recycled polymeric materials : A review 2008 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 293:4, s. 274-297 Forskningsöversikt (refereegranskat)abstract 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.
43.	Vouyiouka, Stamatina N., et al. (författare) A green route for the preparation of aliphatic polyesters via lipase-catalyzed prepolymerization and low-temperature post polymerization 2013 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 298:6, s. 679-689 Tidskriftsartikel (refereegranskat)abstract Lipase-catalyzed polycondensation of two biobased diacids, 1,12-dodecanedioic acid and 1,14-tetradecanedioic acid, with 1,8-octanediol was achieved using immobilized Lipase B from Candida antarctica. The procedure resulted in partially renewable prepolymers, while poly(octylene adipate) from petroleum-based adipic acid was also synthesized for comparison reasons, revealing a dependence of the enzymatic polymerization degree on monomer composition. The prepolymers were further submitted to bulk postpolymerization at temperatures in the vicinity of their melting point under flowing nitrogen. The intrinsic viscosity increase was found up to 12%, with no significant impact on the polyesters thermal properties.
44.	Yadav, Nisha, et al. (författare) Degradation of Cellulose Acetate in Simulated Aqueous Environments : One-Year Study 2022 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 307:6, s. 2100951- Tidskriftsartikel (refereegranskat)abstract Cellulose acetate (CA) is subjected to different aqueous environments (e.g., lake water, seawater, artificial seawater) under controlled laboratory conditions to investigate the degradation potential in natural water systems. The main changes in the CA films are detected during the first months of the 12-month study. Approximately 5% and 10% weight losses are observed during the first month of aging at RT and at 60 °C, respectively. The temperature effect is rather negligible and the weight loss also does not significantly increase on prolonged aging. A quantitative high-performance liquid chromatography analysis shows that this weight loss is mainly caused by deacetylation and depending on the aging conditions, 10–30% of the acetate groups are lost during the first 1–3 months of aging. Fourier transform infrared and nuclear magnetic resonance analyses further support this. It is well established that a high degree of substitution (DS) is the bottleneck for biodegradation of CA and a significantly higher biodegradation rate has been demonstrated for CA materials with degree of substitution, DS<2, compared to those with DS>2. The degree of deacetylation observed here is enough to decrease the DS to below 2, which can therefore have a significant effect on the subsequent biodegradation.
45.	Zhang, Shi-Li, et al. (författare) Preparation and characterization of polyurethane hybrids from reactive polyhedral oligomeric silsesquioxanes 2006 Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 291:7, s. 895-901 Tidskriftsartikel (refereegranskat)abstract 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.
46.	Hajizadeh, Solmaz, et al. (författare) Flow-Through-Mediated Surface Immobilization of Sub-Micrometre Particles in Monolithic Cryogels 2014 Ingår i: Macromolecular Materials and Engineering. - : Wiley. - 1438-7492. ; 299:5, s. 631-638 Tidskriftsartikel (refereegranskat)abstract Particles with functional groups on their surface were immobilized on premade cryogels through covalent bonding to maximize the accessibility of the target molecules to the surface of the particles. The physical properties of the composite cryogel were characterized by SEM, texture analysis and nitrogen adsorption. Different key factors affecting immobilization were also investigated, e.g., recirculation time and the number of functional groups on the premade cryogels. It was found that the physical characteristics of the composite cryogels prepared in this way were very similar to those of the primary matrices, while their binding capacity increased in comparison with conventionally prepared composite cryogels. The binding capacities of two different types of composite cryogel were evaluated by studying the adsorption of small molecules (copper ions and Orange G) and a large molecule (thermostable His-tagged exoglucanase).

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