Effect of cooling rate on mechanical properties of carbon fibre fabric and polypropylene composites

In this study, thermoplastic composites were fabricated using carbon fibre fabric and polypropylene. The effects of the cooling rate, which is a process parameter, on the mechanical properties of the composites were investigated. The degree of crystallinity, tensile properties, flexural properties, drop-weight impact, interlaminar fracture toughness, and fracture surface of the fabricated composites were investigated for composites prepared at cooling rates of 0.6, 1.1, 3.2, and 7.1 °C min−1. The increase in the cooling rate during composite fabrication was found to decrease the stiffness of the composite because the degree of crystallinity of the matrix decreased. In addition, the tensile and flexural properties were somewhat reduced, but the energy absorption and fracture toughness were significantly increased owing to the increased ductility. Therefore, the results of this study can be applied to material-design scenarios in which the tensile and flexural properties are somewhat reduced, but high damage tolerance is required in composite material.