Self-Reinforced Polypropylene Composites based on Discontinuous Tapes-An Experimental and Numerical Study of the Influence of Tape Length

The creation of highly oriented, coextruded polypropylene (PP) tapes allows the production of recyclable self-reinforced polypropylene (SRPP) or all-PP composites, with a large temperature processing window and high volume reinforcement content (similar to 90%). The objective of this research is to assess the performance potential of SRPP composites based on discontinuous or short tapes. For this, the critical tape length for effective mechanical reinforcement of aligned discontinuous PP tapes was determined, while the stress transfer from PP matrix to PP tape was investigated in single tape model composites in combination with an optical strain mapping technique. Mechanical behaviour of both single tape as well as aligned tape model composites was evaluated using finite element analysis (FEA) and used to predict the properties of randomly oriented short tape composites. These discontinuous tape SRPP composites may be of interest from a manufacturing as well as recycling point of view. In terms of manufacturing, such systems are of interest as they may show improved formability during stamping or compression moulding operations while from a recycling point of view it would allow the re-use of production waste like cuttings of fabrics or tapes.