Thermo-mechanical characterization of discontinuous recycled/repurposed carbon fiber reinforced thermoplastic organosheet composites
Philip R. Barnett, Stephen Young, Vivek Chawla, Darren Foster, Dayakar Penumadu
Abstract
The integration of repurposed and recycled carbon fibers into high-performance composites is essential to the adoption of composites for automotive structures due to their low-cost, high formability, and reduced environmental impact. When high areal density nonwovens of these fibers are infused with a semi-crystalline thermoplastic resin, organosheets offering competitive mechanical properties can be produced. This study examined the optimization of such composites through multiscale material characterization and post-process annealing. Single fiber tensile tests were used to characterize repurposed and recycled fiber formats. The thermomechanical properties of the polyphenylene sulfide matrix and resulting composites subjected to different post-process annealing conditions were characterized using differential scanning calorimetry, dynamic mechanical analysis, and nano-indentation. Single fiber push-in testing was conducted to evaluate the fiber–matrix interface as a function of annealing. It was shown that statistical methods based on the bootstrap principle successfully identify the effects of post-process annealing, which are otherwise masked by material inhomogeneity. Post-process annealing was shown to be an effective method of improving the resulting mechanical properties of repurposed and recycled carbon fiber organosheet composites, thereby optimizing their properties for use as a high-performance automotive structural material.