CURE KINETICS OF NEAT AND CARBON-FIBER-REINFORCED TGDDM DDS EPOXY SYSTEMS/

The cure kinetics of neat and carbon fiber-reinforced commercial epoxy systems, based on Tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) a nd 4,4'-diaminodiphenylsulfone (DDS) were studied by means of differen tial scanning calorimetry (DSC). Analysis of DSC data indicated that t he presence of the carbon fibers has a very small effect on the kineti cs of cure. A kinetic model, arising from an autocatalyzed reaction me chanism, was applied to isothermal DSC data. The effect of diffusion c ontrol was incorporated into the reaction kinetics by modifying the ov erall rate constant, which is assumed to be a combination of the chemi cal rate constant and the diffusion rate constant. The chemical rate c onstant has the usual Arrhenius form, while the diffusion rate constan t is described by a type of the Williams-Landel-Ferry (WLF) equation. The kinetic model, with parameters determined from isothermal DSC data , was successfully applied to dynamic DSC data over a broad temperatur e range that covers usual processing conditions. (C) 1996 John Wiley & Sons, Inc.