COMPARISON OF MICROWAVE AND THERMAL CURE OF AN EPOXY-AMINE MATRIX

An investigation was carried out into the effect of a microwave cure o n an epoxy prepolymer with a cycloaliphatic diamine mixture, as compar ed to a standard thermal cure. The microwave waveguide and process (pr opagation mode TE(01)) were adjusted to obtain large homogeneous sampl es. The extent of reaction, x, was measured during the microwave proce ssing by size exclusion chromatography and differential scanning calor imetry. A good estimate of x was found using a modified DiBenedetto eq uation correlating x and the glass transition temperature T-g. The hom ogeneity of the samples was checked during the last steps of cure, sho wing the efficiency of the microwave processing and waveguide. The inf luence of the nature of the mold (metallic or dielectric) on the react ion kinetic was also investigated. Samples cured by both thermal and m icrowave processing were characterized by dynamic and static mechanica l properties and then compared with those of fully crosslinked network s, i.e., postcured at a high temperature.