Dimethyl phthalate is widely used as a diluent of hardener for an unsaturated polyester resin. It was investigated that the effect of dimethyl phthalate on corrosion behavior and its mechanism of isophthalic type unsaturated polyester resins. Four kinds of specimens with the different contents of dimethyl phthalate were used for a corrosion test which were performed by immersing them in 30wt% nitric acid solutions at 80°C, The more the dimethyl phthalate content, the less was the flexural strength and modulus of specimens. The corrosion behavior and its mechanism of these specimens changed in the following three steps; physical degradation by swelling, formation of pits, and hydrolytic corrosion. The corrosion depth of these specimens initially increased linearly with the square root of immersion time, then the following a rapid increase with the formation of blisters near the surface of specimens. The reaction of dimethyl phthalate with nitric acid was one of the causes of pit and blister formation. The higher the content of dimethyl phthalate, the lager corrosion rate of the resin. In conclusion, it was clarified that the corrosion behavior of the isophthalic type unsaturated polyester resin was strongly affected with the content of dimethyl phthalate used as a diluent of hardener.

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Aminotriazine novolak (ATN) has been used as a hardener of epoxy resins for copper-clad glass epoxy laminates. 1.0 of phenolic OH / epoxy mole ratio (equivalent ratio) has been recommended up to this time in the ATN / epoxy curing system. However, nitrogen (or amino group) content of ATN should be considered to be a functional group of the hardener. The curing behavior at 1.0 of OH / epoxy ratio, therefore, was examined; this ratio gave the highest glass transition temperature (Tg) and longer gelation time (GT). ATN was more unstable than conventional novolak in heating, and the chemical structure of ATN changed gradually for a longer time at 250°C while little for a short time. Breaking of the bond between aminotriazine structure and methylene group may occur and result in changing the chemical structure to finally generate a free aminotriazine compound. As ATN was more stable under lower temperature conditions, it should be cured with epoxy resins at a temperature below 200 °C within a few hours.

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Claisen rearrangement reactions are used for one of latent epoxy curing systems. In this work, the reaction mechanism and substituent effects for aromatic Claisen rearrangements are investigated by molecular orbital method in order to control those latent epoxy curing systems. A reaction for allyl phenyl ether is examined. First, on the allyl group rearrangement, a chair-type transition state is generated. From the intermediate detected, in the second step, a hydrogen atom is moved intermolecularly to form the product, o-allyl phenol. The N-allylaniline reaction is found to be less favorable than the allyl phenyl ether reaction, both kinetically and thermodynamically. For condensed-ring allyl ether compounds, it is supposed that more intensive orbital interaction between the condensed-rings and the allyl group gives a smaller activation energy.

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A Living anionic alternating copolymerization of ethylphenylketene (EPK) with 4-Allyloxybenzaldehide (ABA) was achieved. When n-butyllithium was added to a mixture of EPK and ABA in tetrahydrofuran at-40°C in the presence of excess amount of lithium chloride, the copolymerization of these monomers proceeded via complete 1 : 1 alternating manner to afford the polyester with a narrow polydispersity. A linear relationship was observed between the molecular weight and the monomer/initiator ratio keeping a narrow polydispersity. These observations along with the successful results in two-stage polymerization indicated that the present copolymerization proceeded through a living mechanism. The incorporated allyl group could be oxidized to afford the polyester having epoxy side chain.

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