Rapid out-of-oven lamination (ROL) for energy-efficient manufacturing of carbon fiber reinforced composites

Abstract

Traditional composite manufacturing typically involves batch processing with long curing cycles in capital-intensive equipment to achieve composites that are constrained to be less than the size of the mold or oven. Here, we report a rapid out-of-oven lamination (ROL) process for energy-efficient and continuous manufacturing of carbon fiber (CF) reinforced composite laminates. The energy efficiency of our process stems from the combination of two distinct features: (i) the direct and simultaneous application of cure-initiating thermal energy and compaction pressure via hot rollers, and (ii) the resulting rapid through-thickness bulk polymerization of CF prepregs infused with catalyzed dicyclopentadiene (DCPD). We investigate the effects of roller speed, temperature, and pressure on the degree of cure and compare the experimentally observed thermal evolution of the laminates with a thermo-chemical computational model. We demonstrate the applicability of our process to CF-based prepregs through rapid manufacturing of unidirectional, cross-ply, and fabric laminates. The resulting composites have high CF volume fractions, low void fractions, and flexural moduli that approach predictions made by Classical Laminate Theory. Composites that are three times longer than the fabricator are manufactured to demonstrate that dimensions are not limited by the size of the processing equipment. The ROL process is estimated to require two orders of magnitude less curing energy by volume and to be significantly less time-intensive than traditional processes. Overall, the rapid, energy-efficient, and continuous nature of the ROL process makes it a good candidate for manufacturing high-quality structural composites in environments constrained by available energy or fabricator size.