The novel Epoxy resins with a high content of benzyl groups at meta-position were synthesized by the reaction of tetramethylbiphenol with benzyl alcohol. The merit of the substituents at meta-position has been proved by their excellent moisture reliability, dielectric properties and flame retardancy. The groups did not retard Epoxidation rate. The origin of the excellent properties were investigated by changing the content of benzyl groups.

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Phenolic resins are one of the oldest synthetic polymers and widely used in the industry due to their heat-resistance, chemical-resistance, dimensional stability and so on. However, the brittle limited to the application of phenolic resins. We attempt to add flexibility and sturdiness to phenolic resins by the formation of molecular composite with flexible linear polymers. In this work, molecular composites of phenolic resin were synthesized by the polycondensation of o-cresol, p-cresol and o-chlorophenol with paraformaldehyde under acidic condition in the presence of poly (ethylene glycol) (PEG). The characterization of the composites was carried out by ¹H, ¹³C NMR and FT-IR measurements. Thermal properties were determined by DSC and thermogravimetric analysis (TGA). The composition of o-cresol resin/PEG composites was affected by the amount of PEG in feed. The glass transition temperature (Tg) of composites became lower with increasing the PEG content in the composite. It was found that the composites showed good compatibility in the wide range of the composition.

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Silver nanorods have been synthesized with poly (vinylpyrrolidone)-assisted polyol reduction method. The observation by SEM and the measurement by EDS clearly showed that the surface of the obtained silver nanorods has been covered with the PVP layer (thickness 40~80nm). The growth of silver crystal appears to be suppressed with an increase in the thickness of covered PVP layer. Comparing with the shape of silver nanorods and the thickness of PVP layer, a possible growth mechanism of silver nanorods has been proposed.

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A novel over coating layer (OCL) was prepared by blending acrylic copolymer and epoxy compound. The OCL material showed a long shelf life at room temperature, but it clouded during post-baking process. The mechanism of the clouding was investigated by NIR, SEM, and AFM. NIR was the especially useful method to follow the reaction between acrylic copolymer and epoxy compound. Through these measurements, it was confirmed that the final reaction extent of the OCL containing palmitic acid was higher than that of the OCL without the acid. The carboxylic acids with a long alkyl group such as palmitic acid reduced the phase separation between the acrylic copolymer and epoxy compound at post-baking process, and resulted in a long shelf life and clear surface condition of the OCL.

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Alumina flake filler, which has a unique shape and high aspect ratio, were used to make epoxy resin composites, and the mechanical properties, thermal conductivity, fracture toughness and thermal shock resistance were investigated. Based on experimental analyses, alumina flake filled epoxy resin possesses excellent mechanical properties and high thermal conductivity in comparison to those of angular and spherical filled epoxy resins. Experiments were also conducted to establish the effects of adding various amounts of alumina filled content on the fracture toughness and thermal shock resistance. The results showed that the fracture toughness increases with increasing volume fraction of filler, and values for the flake filled epoxy resin are comparatively higher than those of angular filled epoxy resin. On the other hand, the thermal shock resistance decreases with the increase in volume fraction of filler, however, resistance for the flake filled epoxy resin was recovered at higher volume fraction values. Moreover, it was observed that the thermal shock resistance and fracture toughness of alumina flake filled epoxy resin is dependent on the mean diameter of the flake filler, and this improving effect is smaller at smaller diameter sizes. Therefore, it was confirmed that the thermal shock resistance and the fracture toughness of the flake filled epoxy resin are significantly dependent by the aspect ratio of the filler. Also, upon visual inspection of the fracture surface specimen after thermal shock treatment, it was observed that the crack propagated selectively according to the orientation and distribution of the plane surface of the alumina flake particles within the specimen; thus, the thermal shock resistance at lower volume fractions of the flake filled epoxy resin is generally decreasing; at higher volume fractions, however, the thermal shock resistance of flake filled epoxy resin is observed to be improving. This is because at higher volume fractions, the presence of fillers not only favors crack promotion but also crack resistance.

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Fiber reinforced plastics (FRP) are recycled to raw material and fuel in cement production. However, this technology is unable to recycle from FRP to FRP and has a problem of cost performance. In order to recycle from FRP to FRP, chemical recycling technologies are being developed by means of depolymerization of thermosets. Among them, the technologies which are expected to be used for commercial production are reviewed. The FRP recycling technology using depolymerization under ordinary pressure is also reviewed.

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The “tree-like model” proposed by Flory-Stockmayer is regarded as a standard statistics of polymer distribution and gelation. By the use of probability generating functions (pgf), “cascade theory” greatly reduces the burden of combinatorial calculation of the tree-like model; it allows the systematic formulation of simultaneous equation of polymer distribution and enable us to calculate the required statistical parameters without explicit expressions of the distribution. The interpretations of rudimentary knowledge of pgf, formulations, derivations, and calculations of cascade theory are shown. Some examples of formulation are illustrated, which include simultaneous equation of vectorial pgf and formulae concerning the average degree of polymerization, gelation point, and distribution of the degree of polymerization in the addition polymerization of diepoxides with diamines. The theoretical progresses of cascade theory are briefly reviewed. Cascade theory has the simplicity of use and possibilities of growing to the practical tool for experimental study.

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