Thermal regulation of vascularized polymer matrix composites for enhanced thermomechanical performance

Fires or other causes of unexpected increases in temperature cause polymer matrix composites (PMC) to fail under mechanical loads easily sustained at room temperature. However, heat can be removed and temperature reduced in PMCs by active cooling through an internal vascular network. During active cooling, fluid is pumped through the channels to transfer heat from the PMC to the fluid. Here we examine the ability of active cooling to enhance mechanical performance and survivability of PMCs under thermomechanical loading. Channels are manufactured into structural PMCs (i.e. carbon fiber/epoxy and glass fiber/epoxy) using the Vaporization of Sacrificial Components (VaSC) technique. During VaSC, a sacrificial template of the intended vascular network is embedded into the fiber preform prior to matrix curing, then removed at elevated temperatures to create a hollow vasculature. Two testing protocols are used to compare non-cooled and actively cooled PMCs under thermomechanical loading. In the first, a flexure test is conducted in a convective environment with temperatures above the glass transition temperature of the composite to compare retention of flexural modulus in the high temperature environment vs. at room temperature. In the second test, the time-to-failure of PMCs under sustained compressive load and one-sided radiant heating is measured. Results demonstrate the dramatic improvement in PMC performance under thermomechanical loading afforded by active cooling.