Properties of Deconstructable Frontally Cured Fiber-Reinforced Thermoset Composites

Abstract

Fiber-reinforced thermoset polymer matrix composites (FRPCs) possess the chemical, physical, and mechanical properties required for applications in critical industries such as defense, transportation, and energy. However, thermoset FRPCs lack sustainable end-of-life management strategies that recapture their desirable thermomechanical properties. Frontal curing with cleavable comonomers is a promising strategy to extend the lifecycle of constituent materials used in FRPCs by decreasing manufacturing cost and improving end-of-life management with little impact on thermomechanical performance. Here, we demonstrate energy efficient, out-of-autoclave manufacturing and fiber reclamation in high-performance carbonfiber/ poly(dicyclopentadiene) (CF/pDCPD) FRPCs. Through vacuum assisted resin transfer molding (VARTM) and through thickness frontal curing, we produce deconstructable high-performance (Vf ~ 50 %, Vv < 2 %) FRPCs with glass transition temperatures over 140°C using four orders of magnitude less energy than conventional bulk curing. We achieve chemical deconstruction by cleaving silyl-ether-containing comonomers and crosslinkers incorporated in the matrix. We recover the oligomeric fragments of the matrix and the in-tact woven fibers. The reclaimed fibers have excellent integrity and show minimal visual evidence of matrix residue. The thermomechanical performance of the deconstructable FRPCs presented is a step towards efficiently manufacturing sustainable FRPCs that do not compromise performance.