Seikei-Kakou

As biodegradable plastics have been receiving a great deal of attention from industry from an ecological view point, a number of plastics with biodegradability have been developed over the years. Biodegradable aliphatic polyesters of high molecular weight, consisting of dihydric alcohols and dicarboxylic acids (Bionolle), have been developed by Showa High Polymer Co. They show excellent biodegradability and mechanical properties. In this study, two types of Bionolle were selected: poly (butylene succinate) homopolymer (PBS) and poly (butylene succinate-co-butylene adipate) copolymer (PBSA). Intrinsic viscosity [η] as a function of molecular weight of PBS and PBSA were evaluated by means of low angle laser light scattering with size exclusion chromatography (SEC-LALLS) and viscometry with SEC (SEC-VISCO). The relationships between [η] and M_w for PBS and PBSA in chloroform at 40°C were: [η]_(PBS)=2.75×10^-4M^0.75 and [η]_(PBSA)=7.12×10^-4M^0.68 respectively, where [η] is obtained in dl/g

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Our previous report proposed a gradual adhesion model for the interface of epoxy resin used as an electric insulator. The model can deal with the flow and gelling of epoxy resin but it cannot deal with the fracture of the interface. In order to solve the fracture problem, two new fracture models are proposed for the epoxy resin interface.
1) One model proposes that partial adhesion remains after the fracture of the interface of epoxy resin occurs. The calculated strain change using this model does not give good agreement with experimental values.
2) Another model proposes that partial adhesion remains after the shrinkage strain from the curing reaction is released by the fracture of the interface. The calculated strain change from this model gives good agreement with experimental values.
These results indicate that the weak adhesion region breaks away when the fracture of the epoxy resin interface occurs. The temperature distribution of the epoxy resin during the curing reaction does not change with the fracture of the interface. The internal stress of the epoxy resin goes up with the adhesion and goes down with the fracture of the epoxy resin interface.

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Self-assembly by full scale phase separation (FSPS) of a polymer blend was investigated as a means of creating a graded structure across the thickness of a film for a polymer blend containing the conductive polymer poly (aniline) (PANT). A graded structure was easily obtained by casting a solution of a polymer blend of PANT and poly (styrene) (PS). After doping the cast films with HCL, the electrical conductivity of the top of the films was found to increase significantly with a very small PANT content while the bottom of the film retained its high resistivity.

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