Charging behavior of adhesive tapes on peeling was investigated for various adherends. In order to measure amounts of charges accurately, a newly designed pre-amplifier was connected between a Faraday cage and an electrometer. The accurate observation process of charging of adhesive tapes was established. Five types of adhesive tapes were used including rubber-type, acrylic-typeand UV polymerization adhesives, and as adherends 11 different polymers, three metals and a silicon wafer were used. The charge amount of adhesives on peeling is correlated to the tribo-electric series of adherends. The plus charge of adhesive tapes on peeling was maximum at the minus end of tribo-electric series of adherends as PTFE or silicone rubber, and the minus charge maximum of adhesive tapes was at PMMA or PC which are plus end in tribo-electric series. Exceptions such as an acrylic adhesive with PC can be attributed to the contact charging between adherends and additive chemicals in adhesive tapes such as tackifier with low molecular weight. Flat charge distributions on adherends were observed in case of UV adhesive tape after UV irradiation, and this flat distribution can be attributed to no electric discharge of UV adhesive tape.

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Recently, benzoxazine has been reported as a new class of high performance thermosetting resin with ring-opening reactivity, which has superior properties such as high heat-resistance, high glass transition temperature (Tg) and small volumetric shrinkage. Various poly-functionalized benzoxazines are prepared from corresponding phenol resins for studies of their properties - exothermic hardening behavior, thermal decomposition and thermo-mechanical properties after thermal curing. The benzoxazines exhibit exothermic hardening at the temperature from 230℃ to 250℃, from the results of differential scanning calorimetric analysis. Thermal decomposition of any cured benzoxazines commence in the vicinity of 300℃, despite their different structures in spacers. Benzoxazine with methylene substituent in phenol-spacers, reveal high residual weight over 50wt% at 700℃. In addition, the benzoxazine with metylene-spacer showed higher glass transition temperature (Tg). The crosslinking densities (ρ) were calculated from the results of dynamic mechanical analysis. Then, relationship between cross-linking density and thermo-mechanical properties were studied. Tg of benzoxazines were risen with increase of cross-linking density, in spite of their similar property on coefficient of thermal expansion. Storage modulus of Benzoxazines at temperature less than Tg was lowered with decrease of crosslinking density. The spacer constituted of benzoxazine structure which affected the modulus and glass transition temperature on the basis of results of dynamic mechanical analysis.

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In order to investigate the tendency to interfacial fracture of adhesion systems in high humidity, three types of experiments were carried out for the adhesion systems which were composed of stainless steel (SUS304) and epoxy resin: the tests in which the water uptake was measured on the adhesion systems, the single-lap shear tests and the observations using fluorescent microscope on the metal/resin interphase. Bisphenol A type epoxy resin was chosen as a resin and ATU amine or DDM (p.p'-methylene dianiline) was used as a hardener. Firstly, stainless steel plates were coated with the epoxy resin, were immersed into water and were measured the time evolution of the water accumulation. From the tests, water uptake of the specimens made from epoxy resin hardened with DDM and stainless steel was found to be greater than that of the epoxy resin bulk. The single-lap shear tests were also conducted to measure the water degradations of the adhesion systems. Finally, new method to visualize the water diffusion and distribution on the interphase was proposed. We used rhodamine B as a tracer. Epoxy resin coated metals were immersed into the solution of rhodamine B. After the immersion, cut profiles of the specimens were observed using fluorescence microscope. Peak intensity was observed on the interphase between the stainless steel and the epoxy resin hardened with DDM.

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