Effects of High-Temperature Storage on the Glass Transition Temperature of Epoxy Molding Compound

This article describes research on changes of glass transition temperature of electron encapsulated polymer-epoxy molding compound (EMC) after thermal oxidation under high-temperature air storage conditions. The evolutions of glass transition temperature of two EMCs with different compositions (different filling contents) under different temperatures (175, 200, and 225 degrees C) and different aging times (100, 500, and 1500 h) were analyzed by dynamic mechanical analysis (DMA) technology. Research results demonstrated that two glass transition temperatures occurred during thermal aging. These two temperatures were the glass transition temperature of the unaged core material (T-g1) and the glass transition temperature of completely oxidized surface material (T-g2). T-g2 increased continuously with the increase of temperature and the prolonging of the aging time. The filling content could have significantly influenced the aging degree of materials.