Unidirectional continuous fiber-reinforced polypropylene single-polymer composites prepared by extrusion–calendering process

Abstract

An extrusion–calendering process was developed to continuously manufacture unidirectional continuous fiber-reinforced polypropylene single-polymer composites (PP SPCs). The process combined “undercooling” property of the matrix and “overheating” property of the fiber, which can not only establish a wide processing temperature window but also enhance the mechanical properties of the final SPCs. The best tensile strength and modulus of the PP SPCs with only 5 wt% fiber content were up to 53.34 ± 3.56 MPa and 1.81 ± 0.14 GPa, 2 times and 1.59 times higher than those of pure PP, respectively, and they also exceeded the theoretical values due to the high performance of the uniaxial fibers and the optimized process. The influences of the die temperature, fiber contents, and fiber distribution were studied. Scanning electron microscopy was also used to observe the morphological properties of the PP SPCs.