Biodegradable polyester emulsions are generally hydrolyzed, the molecular weights are decreased, and their adhesive properties are deteriorated, even in indoor atmosphere. Therefore it is extensively required to estimate the life span of those adhesives by a simple but reliable method before their applications. Considering the fact that the threshold molecular weight at which adhesive property disappears is found to be different, depending on the cases, even if the same biodegradable emulsion is used, the following formula is derived to estimate the life span of those emulsion adhesives:Tx = (K1/Kx)T1where Tx is the life span of a particular specimen in the desired conditions, T1 the measured life span of the specimen in an accelerated condition, and K the apparent rate constant of the hydrolysis of the biodegradable polyester emulsion and the 1 and x mean the temperature in the accelerated condition and the desired condition, respectively. The estimated life span of polybutylene succinate-co-adipate emulsion is found to be similar to that determined experimentally and the other three specimens including heat-sealed paper, a piece of grindstone and the emulsion coated paper, are under way of testing.

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The interfacial structure and mechanical properties of polypropylene (PP)/talc (mean particle size of 3.2μm)　composite,　in　which　low　density　polyethylene-b-acrylate　copolymer　(PE-diblock), polypropylene-b-acrylate copolymer (PP-diblock), and maleic anhydride-polyethylene (MAh-PE) were added, were investigated. The influence of interfacial structure formed by PE-diblock, PP-diblock, and MAh-PE in matrix on mechanical properties of the composites were discussed. Talc was surface-treated with γ-glycidoxypropyltrimethoxysilane (GPMS). The composites were prepared by twin-screw extruder. The modulus and yield strength of PP/talc composites increased with the content of the PP-diblock and MAh-PP, but decreased with the content of PE-diblock. The impact strength of the composites remarkably decreased with with the content of the PP-diblock and MAh-PP. On the other hand, impact strength of PP/GMPS-treated talc composite improved markedly by addition of PE-diblock.. Dynamic mechanical properties of PP-diblock/talc composites suggest that interaction between talc surfaces and carboxy-groups of PP-diblock became furthermore steady by treatment of GPMS. Scanning electron micrograph observation of fractured surfaces of specimens suggests that PP-diblock and PE-diblock polymers are exisiting in the interface between PP matrix and talc particles by treatment of talc with GPMS. It was clear that the mechanical properties changed according to the interfacial structure from these result.

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A Tg-less epoxy resin was easily obtained by curing bisphenol A-type epoxy resin with ion-containing polymer as a catalyst. In this system, the storage modulus did not drop and maintained a high level as if the cured resin were in a glassy state even at an elevated temperature such as 300℃. The objective of this study is to make clear what are the requirements in the chemical structure of the ion-containing polymer to obtain Tg-less resins. First, various kinds of ion-containing polymer were synthesized, and epoxy resin was cured by using them as a catalyst. Then, the influences of chemical structure of each ion-containing polymer, such as backbone of main chain, kinds of acid group and cation species, on the Tg-disappearing phenomenon in the cured resin were discussed. It was revealed that both ion pair formed cation of alkaline metal with conjugated base which can initiate anion polymerization of epoxy groups and some aliphatic chain which can suppress the aggregation of ion-containing polymer in liquid epoxy resin were necessary in ion-containing polymer. On the other hand, there was no dependence of the chemical structure of backbone and kinds of acid group on Tg-disappearing effect.

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