Relation between impact properties and filler diameter of polypropylene(PP)/elastomer/filler ternary composite was investigated. Calcium carbonate(CaCO3) particles with a diameter in the range from 120 to 1200 nm were used as filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer(SEBS) was used as elastomer. In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. When SEBS volume fraction is below 0.12, the impact strength increased gradually with the decrease of the CaCO3 particle size. When SEBS volume fraction is above 0.17, the addition of CaCO3 particles with a diameter in the range from 120 to 900 nm was more effective than the addition of those of 1200 nm to improve the impact strength.

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Cured epoxide resins with mesogenic structure are known to relax an internal stress caused by an external thermal stress, in which the stacking structure contributes to bring about a higher mobility of segments. The orientation in the epoxy resin network seems to be affected by π-π interaction. From the speculation, we designed the epoxy resin prepared by the use of [1,1'-Biphenyl] -4,4'-diol as a curing agent, which should have a high π electron density. The resin was thought to contain polydomain structure consist of liquid crystalline phase and show a low internal stress, which led to an excellent adhesive strength to metal frame. The results of our investigation showed that the kneading process influenced on the phase structure and the mechanical and adhesive properties of the resulting material. In the observations by polarization microscope and X-ray diffractometer, no difference on the structure of the liquid crystalline domain except for its size was found. Consequently, the interaction between the domains seemed to mainly affected on the mechanical property of the epoxy resin composition as an adhesive.

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A method for evaluating the interfacial adhesion strength between paint layer and chromate-coated steel sheet were proposed. The adhesion strength was evaluated by the critical strain energy release rate at interfacial crack initiation. To measure the critical strain energy release rate, an End Notched Flexure specimen was used, where an interfacial pre-crack was induced between the paint layer and steel sheet. Two kinds of the steel sheets modified with chromic acid which contained colloidal silica or not were used to measure the critical strain energy release rate. Cohesive interfacial fracture was hardly observed for the both steel sheets. It was observed that the energy release rate increased with the colloidal silica included in the chromate-coated steel sheet. Similar dependency of the silica content on the adhesion strength had been also confirmed in the cross cut tests. This signifies that the interfacial adhesion strength can be evaluated quantitatively by the critical energy release rate.

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