Kinetics and thermal characterization of thermoset cure

TLDR

A new kinetic model is applied with differential scanning calorimetry to determine integral heat of reaction, heat generation rates, and specific heat during isothermal and scanning cure experiments of a polyester. The model accurately predicts isothermal reaction rates and heat of reaction, reveals residual reactivity after cure, and identifies two specific‑heat maxima linked to melt and rubbery transitions.

Abstract

The differential scanning calorimeter (Perkin-Elmer DSC-1) is used to characterize the cure of a general-purpose polyester during isothermal and scanning experiments. The technique is based on a new proposed model for the kinetics of isothermal cure. The model yields results which are in good agreement with experimental isothermal rate of reaction and integral heat of reaction data. It also gives some information about the residual reactivity of the sample after an isothermal cure experiment. With the aid of the proposed kinetic model, it is possible to obtain integral heats of reaction and rates of heat generation at different temperatures during a scanning experiment. The difference between the rate of heat input to the sample and the heat of reaction at any instant during scanning may be used to calculate the specific heat of the sample at the same instant. Specific heat data show two maxima during each scanning experiment. These maxima may be associated with transitions occurring during cure in the melt and rubbery states.