Synopsis: The bio-polyol for the flexible polyurethane foams with high degree of biomass content has been developed, which derived from inedible natural oil in order to prevent petroleum resources waste and carbon dioxide emissions cut. We were able to market in first generation bio-polyol suitable for the standard of the flexible polyurethane foam for seat cushion of a car, but it was difficult to satisfy the physical properties of polyurethane foams for seat cushion with increasing the high degree of the biomass content. We have developed the second generation bio-polyol for molded flexible polyurethane foams with high degree of biomass content by using high purity castor oil fatty acid. This paper describes the effect of purity of castor oil fatty acid and the compatibility with bio and fossil based polyols on the mechanical properties of flexible polyurethane foams.

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Synopsis: The focus of this paper is the dependence of polymerization behaviors of epoxides on initiators involving imidazole (Im), 4-aminopyridine (AP) and 4-dimethylaminopyridine (DMAP). Using these basic initiators, polymerization behaviors of bisphenol A diglycidyl ether were investigated by differential scanning calorimetry (DSC) analysis. Isoconversional method was applied to investigate a conversion-activation energy relationship during the polymerization. The analysis revealed a gradual increase of activation energy with progress of the DMAP-initiated polymerization, whereas a gradual decrease was observed in the Im-initiated and AP-initiated ones. Another remarkable finding in this investigation was the much lower activation energy in the AP-initiated polymerization throughout the polymerization process than in the Iminitiated polymerization, which suggested the advantage of AP as a highly efficient initiator for curing reaction of epoxy resins.

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Synopsis: Properties as thermally latent initiators of highly dissociative salts made of 4-hydroxyphenylbenzylmethylsulfon ium (4-HPBS) or 4-acetoxyphenylbenzylmethylsulfonium (4-APBS) as a cation and bis(trifluoromethanesulfonyl)imide (TFSI), tricyanomethanide (TCM), tetrakis(pentafluorophenyl)borate (TFPB), or hexafluoroantimonate (SbF6) as an anion were examined for cationic polymerization of various epoxides. The polymerization activity of the anion was in the order of TFPB > SbF6 > TFSI > TCM. The polymerization activity of the highly active salts using 4-HPBS as a cation, 4-HPBS・TFPB and 4-HPBS・SbF6, were compared with the salts having 4-APBS as a cation, 4-APBS・TFPB and 4-APBS・SbF6. Although the polymerization activity of the salts with 4-APBS as a cation was higher than that of those with 4-HPBS as a cation, the room temperature storage stability was much lower. Based on these results, 4-HPBS・TFPB is considered to be the most promising salt as a novel thermally latent polymerization initiator.

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Synopsis: Today higher electrical performance in Information and Communication Technology is getting required and also, of course, in printed circuit board (hereinafter referred to as “PCB”). PCB using Poly phenylene ether (PPE) is very effective for high data transfer rate and for reduction of transmission loss as PPE has lower D_k and D_f, whereas it had some issue of low process-ability and low solder heat resistance of PCB which attribute to high melt viscosity and low reactivity of PPE. We focused on low molecular weight PPE and were successful to apply PPE to PCB by changing thermoplastic resin PPE to unique thermosetting resin. Newly developed thermosetting resin system contains a large quantity of PPE as it is low melt viscosity. Furthermore, it was found out that hydroxyl terminated low molecular weight PPE has higher reactivity than high molecular weight PPE by this study. Moreover, copper clad laminate with this PPE and epoxy resin has higher glass transition temperature and lower dielectric property.

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Synopsis: A new class of polymer hydrogels, nanocomposite hydrogels (NC gels), consisting of a unique organic (polymer)/inorganic (clay) network structure, was synthesized by thermal-initiated and photoinitiated in-situ free-radical polymerization in the presence of exfoliated clay nanoparticles in an aqueous system. The resulting NC gels overcame most of the disadvantages associated with chemically cross-linked hydrogels, such as mechanical fragility, structural heterogeneity, and slow deswelling rate. By using thermo-sensitive poly(N-isopropylacrylamide), thermo-stable poly(N,N-dimethyl acrylamide) and their copolymers as a constituent polymer, NC gels with remarkable mechanical, optical, and swelling properties as well as thermo-sensitivity were obtained. All the excellent properties and new stimuli-responsive characteristics of NC gels are attributed to the unique polymer/clay network structure. In this review, on the basis of the proposed organic / inorganic network structure model, the polymer/clay network structure were discussed in detail from various points such as the molecular weight and thermo-sensitivity of constituent polymer, the network stability and its modification, the critical clay concentration for network structure formation, self-healing behavior, swelling as a polyelectrolyte gel, and chemically modified network structure.

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[in Japanese]

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[in Japanese]

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