Hamaker constant between two solid surfaces is one important physical factor due to van der Waal's interaction. By measuring the adsorption force F[N] to the solid surface with a mico tip (curvature radius of tip apex R[m]). Hamaker constant A[J] can be obtained experimentally. Mean while, based on Lifshitz theory, Hamaker constant A between solid surfaces can be calculated with refractive index n and relative dielectric constant ε of the tip-sample materials. In this study, the positive correlation between two Hamaker constants obtained by these different methods is clearly confirmed. The validity and effectiveness of Hamaker constant analysis by the probe method can be confirmed. The possibility of identification of sample materials by this method is also discussed.

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Adhesion durability of polyethylene/adhesive polyethylene coated steel with and without epoxy primer in distiled water at 25~80℃ were investigated Temperature dependence of time to 20, 50, 100 Ncm-1 for 90 ° peel strength after immersion test shows Arrenius equation. The apparentactivation energy from the Arrenius equation is the almost same as that of diffusion coefficient for water through polyethylene coating. The adhesion durability at the lower temperature is predicted by using Arrenius equation.

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We tried to improve the fracture toughness by using an aromatic polyamide resin as a high molecular weight curing agent. With the addition of the aromatic polyamide, the heat stability of the cured epoxy resin increased beyond the additive low and fracture toughness simultaneously increased. It was considered that the improvement of the heat stability was due to the increase in the crosslinking density and the introduction of stiff aramid segment into epoxy networks.The fracture toughness was improved by an increase in the homogeneity of the micro-structure and the pinning effect of the rigid polyamide molecules introduced in the networks as an high molecular weight curing agent.

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