Application of differential scanning calorimetry to cure optimization and quality control of a vinyl ester resin

Abstract To optimize cure time for a given resin, the relationship between time, temperature, and degree of cure must be established. Using an epoxy‐based vinyl ester as an example, these relationships were determined with the use of differential scanning calorimetry (DSC). DSC curves can indicate the glass transition temperation ( T _g ) and the residual cure exotyherm (RCE) peak of a plastic of composite smaple. With increasing degree of cure, ( T _g ) increases, and the RCE peak area decreases. The data confirms a model showing that various timetemperature combinations can lead to the same degree of cure. Graphic representations of the relationships between time, temperature, and degree pf cure presented, which include degration regions (here, both T _g and shear strength are lowered). Graphs may be used for optimizing production cure conditions and for setting quality control criteria. This method should be applicable to most thermoset resins.