Thermo-Mechanical Properties of Thermoset Polymers and Composites Fabricated by Frontal Polymerization

Abstract

Thermoset polymers are commonly used as the matrix material in fiber-reinforced polymer composites (FRPCs) due to their good mechanical properties, chemical stabilities, and ease of manufacturing. Conventional curing of thermosets and their composites requires heating the matrix monomers at elevated temperatures during long cure cycles for producing fully crosslinked polymers, resulting in high manufacturing cost in terms of time, energy, and capital investment. Frontal polymerization (FP) is a promising approach for rapid, energy-efficient fabrication of high-performance thermosets and FRPCs. In FP, a thermal stimulus (trigger) causes a self-propagating exothermic reaction wave that transforms liquid monomers to fully cured polymers, eliminating the need for external energy input by large ovens or autoclaves. We have used the FP of dicyclopentadiene (DCPD) to successfully fabricate thermoset polymers and composite parts. In this novel curing strategy, the final degree-of-cure of the polymer, and thereby its mechanical performance, is governed by the heat transfer phenomenon that occur at the polymerization front. During the fabrication of FRPCs some fraction of the generated heat is absorbed by continuous fibers or lost through the tooling. In this work, we will discuss the characterization of the thermo-mechanical properties of DCPD polymer manufactured by FP curing.