Simulation approaches for the mechanisms of thermoset polymerization reactions

Abstract

Abstract Detailed modeling and simulation of the reaction of alcohol and isocyanate moieties to form urethane have provided a reason to question conventional opinions that this is a step-growth polymerization process. In particular, industrial formulations are dominated by catalytic mechanisms, and these chain mechanisms can change the polymer growth mechanism. This paper's research evaluates experimental data of reaction temperature and resin viscosity of urethane gel reactions that substantiate a chain-growth mechanism. One of the artifacts of a chain-growth mechanism is the rapid appearance of relatively large molecules that reduce gel point times earlier with step-growth mechanisms.