It has been found that a crystalline cured polymer is obtained by the reaction of 4,4'-oxybis(glycidyloxybenzene) (OBGB) having a diphenylene ether structure and 4,4'-oxybisphenol (OBP). As a result of examining the combined use of OBP and 4,4'-diaminodiphenyl sulfone (DDS) as a curing agent, it was confirmed that crystalline cured polymers were obtained up to DDS ratio of 30 wt% in the curing agent. The use of DDS improved the glass transition temperature and the thermal conductivity, and reduced the coefficient of liner thermal expansion and water absorption due to the crystallinity.

This article represents the synthesis and characterization of polyamic acids and polyimides derived from several bifunctional amines with ethylenediaminetetraacetic acid (EDTA) anhydride using polyaddition followed by chemical/thermal imidization methods. The structural and thermal properties of the obtained polyamic acids and their six-membered cyclic polyimides were determined in detail by using FT-IR, TGA, and DSC analysis. Additionally, this method was also extended to synthesis of networked polyamic acid and polyimide using trifunctional amine and EDTA anhydride.

The purpose of this study was to convert petroleum-derived phenolic resins as an organic binder of mold to natural polymer substances obtained from renewable resources. Starch as natural polymer was thermally decomposed with acid or hydrolyzed with enzyme to afford dextrin. We attempted to use the dextrin dissolved in cold water as a binder of core mold for casting. The binder was uniformly coated on the refractory aggregate to obtain a fluid mold material. The binder is only baked without generation of adhesive strength when the mold material is filled into a heated mold. Condensation of steam occurs by supplying superheated steam to the particle voids of the mold material filled in the molding. The binder gives adhesive strength by swelling and gelatinizing with the condensed water, and the ambient temperature instantly reaches around 100℃ due to the heat of condensation. Subsequently, we found that a core mold can be formed by drying and solidifying or curing the binder though evaporation of the condensed water with the sensible heat of dry steam of 100℃ or higher.

Anionic hydrogen-transfer homopolymerization of N-isopropylacrylamide (NIPAAm) or copolymerization of NIPAAm and acrylamide (AAm) was performed with t-BuOK in DMF at 140℃ for 1 h under 100 W microwave irradiation. Subsequently, 1-chlorobenzylethyl-3,5,7,9,11,13,15-heptaisobutylpentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane (POSS-BnCl) was added to the resulting polymer solution with stirring. After 100 W microwave was irradiated to the reaction mixture at 140℃ for 6 h, POSS units were introduced onto the polymer chain, thus, corresponding hybrid polymer was obtained. It was revealed that the obtained hybrid polymer has not only water repellency but also good adhesiveness. By conventional heating with an oil bath instead of microwave irradiation, however, objective hybrid polymers having POSS units linked to the side chain was not obtained.