A thermosetting resin system for resin-transfer molding based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and BMI was used as the curing agent, and allyl phenyl ether, as the diluent. The viscosity-temperature curve and the viscosity-time curve were used to characterize the processing property of the resin system. The resin system had a long pot life at the injection temperature. Based on the DSC data, a regime for the curing and postcuring cycles was established. The cured resin showed outstanding heat resistance and good flexural properties. Composites based on the resin system and woven glass fabric were fabricated using RTM technology. The composites showed very good flexural properties at room temperature and high retention rates at 200 and 300°C.

Silicone-epoxy resins were synthesized through hydrosilylation of 1,2-epoxy-4-vinyl-cyclohexane with 1,3,5,7-tetramethycyclotetrasiloxane. The siliconeepoxy resins showed high reactivity in the presence of aluminum complex/silanol compound catalysts. Curing of the resins was effected at extremely low concentrations of the aluminum acetylacetonate/Ph 2 Si(OH) 2 catalyst to give hard materials with optical clarity. For the siliconeepoxy resins containing SiÀ ÀH bonds, Al(acac) 3 alone is effective for the curing. The cured silicone-epoxy resins showed excellent UV resistance. An improvement in the lifetime of UV-LEDs was achieved using the silicone-epoxy compositions as encapsulant.

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