Macromolecular Division Commission on Polymer Characterization and Properties Working Party on Thermal Properties of Polymers* Characterization of the Cure of Resins by Differential Scanning Calorimetry

The c u e of resins has long been characterised by using DSC to measure a "heat of reaction" (AH). Unfortunately, although useful as a quality control parameter, AH is rarely equal to the thermodynamic heat of reaction. As a result, derived data such as the extent and rate of reaction are in error and subsequent predictions of the kinetic behaviour may be seriously flawed. This collaborative programme was devised to investigate the magnitude of the problem using a wellbehaved system to obtain conventional data. These were combined with heat capacities of reactants and products to show how errors arise with a variety of baselines. Emphasis is placed on the need for correct physical foundations before the cure kinetics of a particular system can be considered.