Preparation and Properties of Polypropylene/Vapor Grown Carbon Fiber Composite Monofilaments by Melt Compounding

Abstract

Polypropylene (PP)/vapor grown carbon fiber (VGCF) composites by melt compounding using a counter-rotating twin screw extruder were prepared, then by melt spinning PP/VGCF monofilaments with a high draw ratio of 9 were obtained. The properties and structure of the PP/VGCF composites and monofilaments were characterized by tensile testing, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Increasing the aspect and draw ratios resulted in an increase in the tensile strength of PP/VGCF monofilaments. The improvement of the tensile strength was observed for the addition of a small amount of 1 wt%, however, it was not observed for the addition of 3 wt%. Although the composites continued to be aggregates, VGCF was found to disperse in the PP matrix and increased the nucleation speed of the composite monofilaments, thereby leading to an increase in the crystallization rate of the as-spun monofilament owing to nanoscale structures formed from VGCF by drawing.