Epoxy resin composites containing steel grinding chips as conducting filler were subjected to heat cycling tests in order to evaluate the thermal stability of electrical resistance. The effect of the content of grinding chips, magnetization and precure temperature in the curing process was examined, and this resulted in finding the thermal stability to depend mainly on the precure temperature : the higher the precure temperature, the higher was the thermal stability. There was also shown to be a minimum value in the electrical resistance of the composites at the temperature between 50 and 100°C. The ratio to the minimum resistance was found to depend mainly on the precure temperature. It has therefore been clarified that the thermal coefficient of the electrical resistance in the epoxy composites can be controlled by adjusting the precure temperature in the curing process.

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A convenient synthesis of methylene-bridged cyclic resorcinol oligomer (calix[4]resorcinarene) was reported. First, calix[4]resorcinarene octamethyl ether was prepared by the HCl-catalyzed condensation of 1, 3-dimethoxybenzene with paraformaldehyde in ethylene glycol monoethyl ether. The methoxy group was easily converted to hydroxy group by treatment with BBr₃ in chloroform. In ¹H NMR spectra, each proton signal of these compounds is singlet. A novel ionophore based on calix[4]resorcinarene octaester was prepared. The ionophore showed higher affinity for larger alkali cations, K⁺, Rb⁺ and Cs⁺, than for smaller ones, Na⁺ and Li⁺. The ionophore based on C-methylated calix[4]resorcinarene, which was synthesized from resorcinol with acetaldehyde, on the contrary, did not bind alkali cations.

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Recently, lignophenols have been obtained from lignin in wood-sources, and now, the establishment of their use as industrial materials is required. We tried to apply them to positive-type photoresists for printing and printed wiring boards, because they have the advantages of (1) good solublity in alkaline water, (2) sensitivity to UV irradiation and (3) resistance to heat. We used them instead of novolac resins in a novolac/ diazonaphthoquinone system photoresist, resulting in giving photoresists with high sensitivity and less side etching through adding 3-nuclei novolac compounds to lignophenols.

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A part of positrons injected into polymers form positronium (Ps) after loosing their energy through interactions with atoms and molecules. Positron annihilation lifetime spectroscopy (PALS) is capable of determining size, distribution, fraction and anisotropic structure of inter-molecular holes in polymers. The Ps lifetime and intensity in polymers were measured using a short-pulsed slow positron beam system, in which system the Ps lifetime in a polymer near the surface can be measured by changing the injection energies of positron. This measurement has been widely used in the metallographical field; while in the polymer field it has been used only for studies focussed on the simple structures of thermoplastic and thermosetting resins. In this report, the investigation was performed on a phenol-cured epoxy system used as a standard product in the polymer engineering. The result suggested that this polymer had a graded structure near the surface, and the properties of the structure differed from those of the bulk.

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It is possible to fix the structure of the microphase separation formed with block and graft copolymers with incompatible sequences by crosslinking the domains of the microphase separation. When the domains that are crosslinked are isolated in a matrix, the crosslinked products can be assumed as a minimum unit of the microphase separation, and can be useful nano-materials. In this review, the crosslinking of the spherical domains in the microphase separation in the solid state and in the solution is discussed. Additionally, the synthesis of the microspheres with unsymmetrical surface by crosslinking of spherical domains in lamella-sphere structure and discotic structure in lamella-within-cylinder structure, and the network formation of the discotic microspheres in the solution are described.

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