Class-transition temperature-conversion relationship for an epoxy-hexahydro-4-methylphthalic anhydride system

摘要

The DGEBA-MHHPA epoxy system has found increasing applications in microelectronics packaging, making crucial the ability to understand and model the cure kinetics mechanism accurately. The present article reports on work done to elucidate an appropriate model, modified from the empirical DiBenedetto's equation, to relate the glass-transition temperature (T-g) to the degree of conversion for a DGEBA-MHHPA epoxy system. This model employs the ratio of segmental mobility for crosslinked and uncrosslinked polymers, lambda, to fit the model curve to the data obtained. A higher ratio value was shown to indicate a more consistent rate of increase of T-g in relation to the degree of conversion, while a lower value indicated that the rate of T-g increase was disproportionately higher at higher degrees of conversion. The best fit value of lambda determined by regression analysis for the DGEBA-MHHPA epoxy system was 0.64, which appeared to be higher than for those previously obtained for other epoxy systems, which ranged from 0.43-0.58. The highest T-g value obtained experimentally, T-g max, was 146 degrees C, which is significantly below the derived theoretical maximum T-g infinity value of 170. (C) 2000 John Wiley & Sons, Inc. [References: 26]