The Influence of Different Carbon Type Fillers on the Mechanical and Physical Properties of Co-Extruded PP-Based WPC

Abstract

In order to improve the properties of a co-extruded wood-plastic composite (WPC), five different carbon-based fillers, namely graphite (G), expandable graphite (EG), carbon nanotubes (CNTs), carbon black (CB) and carbon fibres (CFs) were introduced into the shell layer of polypropylene (PP)-based WPC. The addition of CB, G, EG and CNTs improved the tensile strength by 45%, 25%, 5% and 32%, respectively; the addition of carbon fibres decreased the tensile strength by 22%. However, the tensile modulus of the composites decreased for all filler types. The incorporation of CNTs and CFs increased the impact strength by 11% and 21%, respectively; the impact strength of CB, EG and G-loaded WPCs decreased by 7%. The incorporation of CB, EG, G, CNTs improved the hardness by 25%, 9%, 25% and 59%, respectively; the addition of CFs decreased the hardness slightly. The wettability of the composite decreased with the CB, CNTs and CFs loadings. The presence of EG increased water absorption, whereas thickness swelling decreased compared to the reference.