Investigation of the mechanical performance of carbon/polypropylene 2D and 3D woven composites manufactured through multi-step impregnation processes

Abstract

In this work, pre-impregnation techniques including Dr. Ernst Fehrer (DREF) spinning and electrostatic powder coating were used to negate the poor impregnation of highly viscous thermoplastics. The DREF spun hybrid yarns and electrostatic spray coated towpregs were woven into 2D and 3D fabrics and subsequently consolidated to yield two variations of 2D and four variations of 3D composites including 3D angle inter-lock and 3D orthogonal weave. The 2D composites possessed higher tensile and flexural strength than the 3D composites. However, better notch impact properties were observed for 3D orthogonal weave. The closer wrapping in 3D orthogonal slightly improves the shock absorption capability of the composite than the angle interlock composite. Composites made from powder coated towpregs performed better than composites made from DREF spun hybrid yarns, minimizing the effect of the weave pattern. Porosity was a common feature of composites manufactured from DREF spun yarns as observed from micro-CT images.