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Time-dependent measurements of X-ray diffraction and infrared spectra have been performed to reveal the thermally induced phase-transition mechanisms about the ferroelectric transition of poly(vinylidene fluoride) form I crystal and the β-to-α transition of trans-1,4-polyisoprene. In both cases, the transitions were found to occur by the mechanism of the melt of the original phase followed by the recrystallization to the another new crystal phase. These findings request us to change our previous understandings of the phase-transition behaviors of these polymers. This time-dependent measurement technique will be helpful for the reinvestigation of the phase transitions of the other polymers also.
Linear ABA-type triblock copolymer with poly(tetrahydrofuran) (PTHF) and poly(2-ethyl-2-oxazoline) (PEOxz) was synthesized by a one-pot sequential copolymerization, utilizing the living cationic polymerization of both monomers. Films of the ABA-type copolymer configure PTHF pure phase and mixing phase of PTHF and PEOxz, which was attributed by differential scanning calorimetry thermograms and wide-angle X-ray diffraction profiles.
This paper deals with temperature-dependent conductivity for polymer-filler composites by using nonparabolic function as potential barrier. The good agreement between theoretical and experimental results indicates that the evaluation by the fluctuation-induced tunneling effect is important to analyze temperature dependence of the conductivity of the polymer-filler composite systems except in the temperature ranges associated with the β and the γ relaxations.
Transport of toluene or 2-methylnaphthalene through nanoporous syndiotactic polystyrene (sPS) film. The δe-sPS was used as a film for transport measurement of toluene or 2-methynaphthalene in hexane. These solutes basically transport in the non-crystalline regions of the polystyrene. The δe-sPS crystal is characterized by the nanopore in the unit cell, which is enough space for toluene to transport, but 2-methylnaphthalene is too large to transport in the pore. This results in low flux of 2-methylnaphthalene in the δe-sPS film.
We found that the tensile strength and modulus of the hydrogenated styrene-b-styrene-co-butadiene-b-styrene triblock copolymers distinctly increased with increasing the degrees of hydrogenation (DHs). The enhancement of the mechanical properties is attributed to the increase in the segregation of the microphase structure by increasing the DHs owing to the increase in the incompatibility of polystyrene and hydrogenated SB block segments predicted by the solubility parameter difference.
We synthesized the poly(N,N-dimethylacrylamide)-based resin R2 and the new TentaGel resins T3 and T4 obtained via immobilization of substrate-like inhibitors of copper amine oxidases (CAOs) onto commercial TentaGel S-Br. We used polyacrylamide gel electrophoresis experiments to determine the capability of the prepared resins to capture plasma amine oxidase (PAO) and diamine oxidase (DAO), members of the CAO family. The poly(N,N-dimethylacrylamide)-based resin R2 proved to be the first insoluble polymeric material capable of capturing enzymes of the CAO family such as PAO and DAO.
Donor–acceptor (D–A)-type alternate polymers were synthesized, with either dithienyldithienosilole or dithienosilole as the donor and pyridine as the acceptor, and they exhibited broad absorption peaks at approximately 520 nm. Complex formation of the polymers with B(C6F5)3 was examined, revealing even broader absorption peaks, with the edges red-shifted relative to the parent polymers. These polymers and complexes were applied to bulk heterojunction-type polymer solar cells and dye-sensitized solar cells.
The synthesis of a novel diol monomer containing phosphorylcholine (PC) unit was carried out, and PC-containing polyurethanes were prepared by polyaddition of the diol monomer and poly(carbonate diol) with 4,4′-diphenylmethane diisocyanate. According to the thermal analysis and the stress–strain measurements, it was found that polyurethane films exhibited the thermal stability up to 250 °C and the elastic properties with high tensile strength. It was also confirmed that the PC-containing polyurethane film efficiently reduced the protein adsorption on the surface.
UV irradiation cleaves chemical bonds and decomposes the silk chains into fragments. The effects of UV irradiation on spider silk were studied from the viewpoint of the quantity of silk proteins. The ratio of the uncleaved quantity to the initial quantity for the spider silk and silkworm silk is plotted as a function of the UV irradiation time. The silkworm silk decomposes more easily than the spider silk. The result indicates that Nephila clavata spider dragline was 1.7 times more resistant to UV irradiation than silkworm silk.
