Impact energy absorbability of carbon fiber reinforced composites (CFRPs), in which carboxyl terminated butadiene acrylonitrile rubber (CTBN)/ epoxy reactive blend resins were used as the matrix resins, was evaluated. As the matrix resins, 2 types of CTBN/epoxy blends, in which microphase separated morphologies composed of epoxy-rich phase and rubber-rich phase exist, and 1 type of CTBN/epoxy blend, in which no phase separation was observed by electron microscopy, were compared. The rank order of energy absorbabilily of the resins was consistent with the rank order of that of the CF fabric composite laminates. However, the elastic moduli of the resins decreased with the increase of the energy absorbability. The trade-off relationship between the modulus of elasticity and the energy absorbability was also shown in the CF fabric composite laminates. Then, hybrid composite laminates which consist of the CF fabric prepregs impregnated with CTBN/epoxy blends and uni-directional CF reinforced prepregs impregnated with conventional rigid epoxy resin were fabricated. The hybrid laminated composites indicated improved balance on the modulus of elasticity and the energy absorbability.

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A simple visualization technique to observe stereoscopic structures inside thin adhesive films was developed, and the relationship between the interfacial debonding process and the cavitation behavior in the probe- tack testing was studied. We found that as we decrease the cross-linking density we get more adhesion energy, and also found that this tendency is related to the blunting of the edge of the cavities.

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Polysilsesquioxane having chloromethylphenyl groups was employed for the grafting of the copolymer of butyl acrylate (BA) and methyl methacrylate (MMA) by ATRP process. Through the examinations concerning the conditions of the grafting of BA, the combination of copper (I) bromide and ( - ) - sparteine was found to be effective for the graftation. This polymerization system was applicable to the successful introduction of the block copolymers of BA and MMA, in which the sequence of the corresponding polymers was changed. The adhesive properties of the grafted polysilsesquioxanes such as peel strength and holding power were evaluated and were found to be affected by the sequence of the polymers in the graft chain. The both properties were improved by the presence of the polymer of MMA located near the polysilsesquioxane main chain. On the other hand, when the polymeric MMA was placed in the end of the graft chain, adhesion force was decreased but the holding power was increased markedly.

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