An improved kinetic model for the autocatalytic curing of styrene‐based thermoset resins

Abstract

SynopsisThe cure behavior of styrene-based thermosets such as orthophthalic polyester, isophthalic polyester, and vinyl ester resins is characterized using both isothermal and dynamic differential scanning calorimetry ( DSC) techniques. In the conventional autocatalyzed kinetic model, it is assumed that the isothermal cure reaction of a thermoset goes to completion, which usually leads to a poor fit with the DSC kinetic data. It appears from the conversion-time profiles that the cure reaction reached a plateau value (a,) less than unity. This is not unexpected, as the molecular mobility of the resin system decreases as the network cures. In this work, we have refined the model to remove this restrictive acsumption by taking the total ultimate conversion (a,) into account in the computation. This improved model permits us a better prediction of the course of the cure reaction of the styrene-based thermosets under isothermal and dynamic conditions. In addition, the cure kinetics of the three thermoset resins are studied and compared on the basis of several kinetic parameters including conversion, cure rate, reaction rate constant, heat of cure reaction, half-life, and Arrhenius parameters. The reactivity of these resins when arranged in ascending order is found to be: vinyl ester < orthophthalic polyester < isoththalic polyester.

Effects of initiators on the cure kinetics and mechanical properties of vinyl ester resins

“…[11][12][13][14][15] In most of them, the same conclusion has been drawn: with increasing temperature, Q I increases, whereas the residual heat decreases, and Q T is nearly constant within the temperature range studied. However, this is not the case for the reaction heats studied here.…”

Cure kinetics of light-activated polymers

“…It is interesting to note that in their analysis of the data on styrene-based thermosetting resins, Lam et al 24 suggest a purely mathematical transformation to reduce their empirical rate equation to a simpler expression for the case when the total reaction order is 2. Their reduced expression for X(t) is of the same form as our eq.…”

Modeling of Conventional Autoclave Curing of Unsaturated Polyester Based Composite Materials as Production Process Guide

“…It is the most widely used and describes free radical polymerization [4] [17][18]. It is expressed as;…”