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Melt blending of polylactide (PLA) and biodegradable polyamide elastomer (PAE) has been performed in an effort to toughen the PLA. DMA tests showed good compatibility between PAE and PLA blends, and the PAE were dispersed in PLA matrix uniformly shown in SEM photos. Mechanical properties of blends with different PAE concentrations were observed. With the PAE contents increasing, the elongation at...
The surface and interfacial properties of different high performance fibers of current interest have been analyzed. The pyridobisimidazole fiber M5 shows a markedly higher polar contribution to its surface free energy than the rest of the organic fibers under study. Interfacial shear strength (IFSS) values measured by means of the microdroplet test indicate that M5 fiber has an IFSS that doubles that...
The synthesis of ethylene-co-5,7-dimethylocta-1,6-diene copolymers (CEDMO) with different molar DMO contents has been performed to incorporate double bonds in the lateral and make easier the development of crosslinkings in the resulting polymer material after application of electron-beam irradiation. The gel content as well as a comprehensive evaluation of the changes in the crystalline characteristics...
A series of amphiphilic graft polyphosphazenes with hydrophilic weight fraction ranging from 0.40 to 0.55 were synthesized. These copolymers could self-assemble into distinct aggregates in aqueous solutions. Spherical micelles were observed for the copolymer sample with higher hydrophilic weight fraction. However, when the hydrophilic weight fractions decreased to less than 0.50, vesicle-like polymersomes...
Cyclization reaction products by the end-to-end ring closure of telechelic polystyrenes (PSs) with molecular weight of 47k and 380k in THF (good solvent) and also in cyclohexane (poor solvent) were characterized by SEC connected with multi-angle light scattering (MALS). By comparison of the SEC peaks of the monomeric rings from 47k-PSs in THF and cyclohexane, there is no essential difference both...
A random poly(lactic acid), PLA, based ionomer was synthesized by copolymerizing a methacrylate-terminated PLA macromonomer and methyl methacrylate. The copolymerization kinetics were studied using 1 H NMR spectroscopy and the copolymer composition was characterized by 13 C NMR spectroscopy. Carboxylic acid groups were introduced into the copolymer by reacting the hydroxyl end groups...
Electrospinning is known to produce nanofiber nonwovens with lateral dimensions in 10cm up to the meter range meeting thus requirements characteristic of filter, textile or even tissue engineering applications. For particular applications other types of deposition pattern are of benefit (i) in which the deposition area is strongly limited in the lateral dimension, (ii) in which a linear deposition...
Copolymers of poly(ethyl cyanoacrylate-co-methyl methacrylate) (PECA-co-PMMA) with various compositions were synthesized by free radical bulk polymerization in an effort to control degradation and stability as well as glass transition temperature to overcome intrinsic poor processability of the poly(ethyl cyanoacrylate) (PECA) homopolymer. The copolymers were found to have an alternating random tendency,...
An “in situ” method for the production of akaganeite polymer nanocomposites is described. A controlled precipitation is achieved by using a polymer matrix, polyvinylpyridine, containing N-base functional groups that form coordination bonds with iron ions. The resulting materials have permitted the observation of two sources of magnetic moment in akaganeite nanoparticles: (1) finite size effects with...
The phase behaviors of aqueous polymer solutions are known to be affected by the presence of ions even if the polymer itself does not have any charges. We studied the effect of salt (sodium chloride) on the eutectic phase behavior of non-ionic polymer, poly(ethylene glycol) (PEG) in aqueous solutions using differential scanning calorimetry. We observed that the addition of NaCl increased the liquidus...
A facile method to the synthesis of polymer cryogels employing the UV irradiation technique and hydrogen peroxide as initiator is presented. Various cryogels composed of either biocompatible, biodegradable and/or temperature-responsive polymers are synthesized from polymer or monomer precursors. It is found that due to the macroporous structure, the cryogels exhibit a very rapid water uptake and,...
A series of poly(ether ketone sulfone)s were synthesized from 1,4-di(fluorobenzoyl)cyclohexane, difluorodiphenylsulfone and bisphenol A. These polymers were characterized by NMR, IR, SEC, DSC, TGA, tensile tests and DMA. The results from NMR, IR, and SEC indicated that essentially no side reactions, such as cross-linking, associated with enolate chemistry take place during the polymerizations although...
This feature article summarizes recent advances in an emerging three-dimensional (3D) imaging technique, transmission electron microtomography (TEMT), and its applications to polymer-related materials, such as nanocomposites and block copolymer morphologies. With the recent developments made in TEMT, it is now possible to obtain truly quantitative 3D data with sub-nanometer resolution. A great deal...
Several liquid crystalline polysiloxanes (Pa–Pf) bearing fluorinated mesogenic units were synthesized using poly(methylhydrogeno)siloxane, 4′-(4-undec-10-enoyloxy-benzoyloxy)-biphenyl-4-yl 4-fluoro-benzoate and 4′-propionyloxy-biphenyl-4-yl 4-allyloxy-benzoate, and effect of fluorinated mesogenic units on phase behaviors of the fluorinated LC polysiloxanes was studied as well. The samples Pa and Pb...
A macroporous amphoteric membrane was successfully prepared by solution blending of a natural polymer chitosan (CS) and its derivative carboxymethylchitosan (CMCS). The adsorption of two model proteins (ovalbumin and lysozyme) with very different pI values on this CS/CMCS blend membrane was investigated in batch systems. The results showed that both proteins could be effectively adsorbed on the membrane,...
A basic problem with many promising solid electrolyte materials for battery applications is that crystallization in these materials at room temperature makes ionic mobilities plummet, thus compromising battery function. In the present work, we consider the use of a polymer additive (polyethylene oxide, PEO) to inhibit the crystallization of a promising battery electrolyte material, the organic crystal...
The interface structure of the poly(ethylene terephthalate) (PET)/silica nanocomposites was characterized by Fourier transform infrared and solid-state nuclear magnetic resonance. Our study reveals that PET chains are grafted onto the surface of silica nanoparticles, and they form branched and lightly crosslinking structures during the polycondensation. Gel permeation chromatography measurements indicate...
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