Three types of reworkable dimethacrylates having hemiacetal ester moieties were synthesized. Thermal curing and thermal decomposition of cured dimethacrylates were investigated. When the films of reworkable dimethacrylates containing α,α-azobisisobutyronitrile were baked at 120℃ under N₂, the films became insoluble in solvents. After the subsequent baking above 180℃, the films became soluble in solvents. The reaction mechanism was studied by FT－IR and MS spectroscopy.

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Cresol (Cre) formaldehyde (Form) novolac resins (Cre/Form) having hard properties cannot be applied minutely the positive-type photoresist material onto dry films. Therefore, a new development was needed, so we carried out the synthesis and application of cresol novolac resins having flexibility. The polycondensation stepwise reactions with m-cresols (m-Cre) and n-butyraldehyde (Bu) succeeding reaction with m-Cre and glutaraldehyde (Glu) were carried to obtain m-cresol butyraldehyde-glutaraldehyde novolac resins (m-Cre/Glu－Bu). m-Cre/Glu－Bu meeting the conditions of both a dissolving ratio for alkaline aq. below 300 Å/sec and M_w over 2000 were chosen for the obtained resins. 5μm thick cast films for applying onto the polyimides were prepared in order to evaluate the flexibility properties of the obtained resins by observation for their bent parts. Though the Cre/Form resin was scattered, the m-Cre/Glu－Bu resin was settled with just cracks. The flexibility of the m-Cre/Glu－Bu resin was confirmed from results of the dynamic storage modulus measurement, too. The lithography performance of the m-Cre/Glu－Bu resin coated at a 1.5μm thickness onto the silicon wafers was examined. The residual membrane thickness was high (97％) and the resist pattern was able to draw up to 4.0μm clearly.

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3,3’-(methylene-1,4-diphenylene)bis(3,4-dihydro-2H-1,3-benzoxazine) (P-d type benzoxazine, P-d) was toughened by two different toughening technologies. Toughening by employing in situ generated alternating copolymer of styrene with N-phenylmaleimide (PMS) as modifier could not be applied to P-d owing to the inhibition of a propagation of PMS polymerization in the presence of P-d. Therefore, we employed bisphenol-A diglycidylether (DGEBA) as a medium for radical polymerization of PMS. Phase separated structure in cured resins was given by the employment of DGEBA, and thus fracture toughness (K_IC) was increased by 55%. On the other hand, the solubility parameters (SPs) of the modifier monomers were judiciously manipulated to prevent the inhibition of in situ generation of modifiers, by selecting novel modifiers, such as n- butyl methacrylate and styrene, with SPs that differ from SP of the matrix. By adopting this approach, K_IC of P-d modified with novel in situ generated modifiers was successfully increased by 43% without sacrificing flexural strength that is unique property of polybenzoxazines.

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Hybrid organic－inorganic polymers were synthesized through hydrosilylation of 1,3,5,7-tetramethylcyclotetrasilox ane (TMCS) and divinyl-terminated tetramethylsiloxane (DTMS) monomers. Controlling the hydrosilylation reaction by varying the feeding ratio as well as the total monomer concentration, chemically-soluble TMCS－DTMS hybrid polymers were obtained as a liquid state. The resulting polymer was colorless and viscous liquid, seemingly took linearly elongated structures without no remarkable gel-form. Unreacted Si－H groups remained in the polymer, which allowed network formation of the TMCS－DTMS hybrid polymer with various crosslinkers such as DTMS, divinylbenzene (DVB), 3,3’-divinylbiphenyl (DVBP), and di(ethyleneglycol) divinylether (DEG). Consequently, transparent and thermally stable hybrid networked polymer films with a thickness of ca. 0.2 mm were prepared through hydrosilylation and self-condensation reaction under curing process, which was proved using FT－IR spectroscopy.

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To improved performance of the epoxy resin, an allyl group and hydroxymethyl group were introduced into epoxy resin. Maleimide modified epoxy resin was synthesized by the reaction of epoxy resin having allyl group with N-phenylmaleimide. Glass transition temperature and lap shear adhesive strength aged at 200℃ of cured maleimide modified epoxy resins were higher than those of cured commercial epoxy resin (DGEBA). Urethane modified epoxy resin (EPCI) was synthesized by the reaction of epoxy resin having hydroxymethyl group with isocyanate prepolymer. And siloxane modified epoxy resin (ECDG) was synthesized by the reaction of epoxy resin having allyl group with hydride terminated polydimethylsiloxane. Fracture toughness and adhesive properties of cured EPCI and ESDG were superior to those of cured DGEBA.

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Phenolic resin is the oldest total synthesized plastic commercialized by Belgium-born American engineer Dr. Leo H.Baekeland in 1907 industrially and over 100 years have passed. During this time, the phenolic resin which has excellent heat resistance, strength and so on good performance with relatively inexpensive, is used extremely and widely evolving and adapting to suit new high technology market added to consumer usual goods. In this paper, the recent development of phenolic resin about basic skills of synthesis and curing method and mechanism mainly, and from the point of view of the green chemistry, recycling of cured resin and natural phenolic resin raw materials are reviewed.

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