The epoxy resin derived from pyrogallol (1,2,3-trihydroxybenzene) was synthesized and investigated for its physical properties. Pyrogallol tends to have byproducts with cyclic structures due to three adjacent phenolic hydroxyl groups, which differs from conventional epoxidation process. For suppressing these byproducts, an epoxy resin (PyTGE) exhibiting a liquid form was obtained industrially, by separating the addition reaction and the ring closure reaction. Cured materials of PyTGE and 4,4’-diaminodiphenylsulfone showed both high modulus and high strength. In the PyTGE cured product, the free volume corresponding to the void part was small, and it is assumed that a denser (condensed) network structure was formed by the adjacent epoxy units. In addition, in verification using model compounds, the catechol-type epoxy might form a 11-membered cyclic structure consisting of an amino group, and the cyclic molecules affected the properties of the cured products.

Formation mechanism of phase-separated structure of compounded composition of vinylsilyl group-terminated polyphenylene ether (VS-970) and hydrogenated styrene-butadiene block copolymer (SEBS) developed for high-speed communication multi-layer laminate applications was investigated. A mechanism was suggested in which nano-scale of dispersion consisted from butadiene-derived blocks of SEBS (P(E-B) blocks) present in the VS-970/SEBS composition grow during the curing process to form isolated phases. Whereas the polystyrene blocks (PS blocks) in SEBS dissolve in the polyphenylene ether (PPE) phase and located around the P(E-B) block dispersion, affecting the aggregation behavior of the P(E-B) blocks dispersion during the curing process. When SEBS with a low PS content is used, aggregation of P(E-B) blocks proceeds and a morphology containing a large elastomer phase of 100 nm size is formed. The cured product with a large elastomer phase exhibits a low dielectric loss tangent (D_f) value, and this phenomenon was also confirmed in additive formulation systems such as reactive diluents. Laminates using VS-970 show a D_f value (0.0029@10 GHz) that is 20% lower than the current technology, and every property such as T_g, solder heat resistance, and copper foil peel strength also satisfies the preliminary required properties.

Poly(4-ethynylaniline) [poly(1)] coordinated to palladium nanoclusters (Pd NCs) were prepared. The coordination of Pd NCs was confirmed by X-ray photoelectron spectroscopy and scanning transmission electron microscopy. Pd NCs were coordinated with the benzene rings as well as amino groups of poly(1). Pd NCs were partly coordinated with the polymers, maintaining their original size to form the aggregates with sizes of several tens to hundreds nanometers. Pd NCs coordinated with poly(1) efficiently served as catalysts for the Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions.

Although all the isotopes of bismuth are radioactive, the most abundant ²⁰⁹Bi can serve as a stable isotope owing to its very long half-life. Bismuth is an attractive heavy element for inorganic components of organic–inorganic hybrid materials. As an element, bismuth exhibits unique features such as high atomic refractivity, X-ray shielding property, and heavy atom effect. Furthermore, typical bismuth compounds are less toxic and inexpensive. However, appropriate molecular designs are necessary for the synthesis of bismuth-containing polymers with sufficient stability, since typical Bi–C bonds are weak. In this comprehensive, we survey research on the synthesis of functional bismuth-containing network polymer films by radical polymerizations of bismuth (III) methacrylate and styrylbismuthines. These bismuth-containing polymers exhibit excellent and unique properties such as high refractive index, X-ray shielding property, and photochromism.

We have studied thermal conductivity of polymer composite in focusing on the influence factor of thermal contact resistance between fillers, which didn't attract much attention. At first, thermal conductivity of the composite in a dual phase structure was estimated by a finite element method, then it was predicted that the thermal conductivity increased exponentially in the range of phase inversion.Further, we prepared the composite by the SPS molding method in order to form a dual phase structure, and succeeded in creating a percolation phenomenon in the thermal conductivity of polymer composite. We also discovered the method to obtain polymer composite with electrically conductive or insulating fillers, where the thermal contact resistance between fillers was greatly reduced, by using conventional polymer processing (injection and compression molding etc.).