Microwave radiation curing of polymers: Using a temperature equivalent method for cure reaction analysis

Microwave curing has been shown to be a viable alternative to conventional thermal curing of polymers on the basis of significant reaction, rate enhan cements. Proper understanding of the microwave cure reaction kinetics has b een hindered by the lack of an adequate basis relating the process to conve ntional thermal analysis methods. The rate enhancement obtained ill microwa ve curing is shown to have been obtained from the decrease in the lag time prior to initiation of cross-linking, as well as, a decrease in the Effecti ve cure time. Phenomenologically, the shortening of the cure time is no dif ferent from a shortening achieved by a higher curing temperature, thereby p roviding a basis for relating the microwave cure process to thermal curing. This article attempts to relate the test results for both thermal and micr owave curing by obtaining a temperature equivalent value using a phenomenol ogical logarithmic approach. Results show that the equivalent temperature c an be elucidated using a logarithmic plot of the cure times and the glass t ransition temperature. The values of the equivalent temperature so obtained were also consistently and significantly higher than the actual sample tem perature during cure, confirming microwave curing to differ in mechanism fr om thermal curing. (C) 2000 John Wiley & Sons, Inc.