STUDY OF GELATION USING DIFFERENTIAL SCANNING CALORIMETRY (DSC)

A new method for determining the degree of conversion of gelation (alp ha(gel)) and gel time (t(gel)) at gel point using a single technology, DSC, is discussed in this work. Four kinds of thermoset resins are ev aluated. It is found that the mutation points of reduced reaction rate (V.) vs. reaction conversion (alpha) curves, corresponding with the c hanges of reaction mechanism, represents the gelation of the reaction. The alpha at the mutation point is defined as alpha(gel). From isothe rmal DSC curves, the point at alpha(gel) is defined as t(gel). Traditi onal techniques (ASTM D3532 and DSC method) are also used to determine alpha(gel) and t(gel) in order to demonstrate this new method. We hav e found that the results obtained from this new method are very consis tent with the results obtained from traditional methods.