P-19

Plastics are relatively inexpensive, lightweight and durable materials, which can be readily moulded into various products. However, current levels of their usage and disposal generate severe environmental problems. Recycling is one method for reducing environmental impact and resource depletion. In general it is assumed that the mechanical properties of recycled polymers are lower than of virgin materials. Furthermore small levels of pollution are potentially affecting processability and properties. Hence, in industry a large effort is made to clean recyclates, which adds costs to the material price.

In fibre reinforced materials the fibres are substantially responsible for the desired material’s stiffness and strength, while the polymeric matrix binds the fibres, serves to transfer loads and provides its shear strength. The need for economical fibre reinforced thermoplastic composite materials in industrial applications is rapidly expanding. Thus, the main objective of this study was to evaluate the potential of recycled polymers as matrix material for composite tapes. The polymeric materials studied were a virgin polypropylene (PP) and various post-consumer and post-industrial recyclates predominantly made of PP but containing a certain amount (below 10%) of polyethylene (PE). Additionally blends of recycled polymers with a masterbatch, featuring a combination of heat stabilisers and coupling agents, were prepared to compare its effect on the adhesion between fibre and polymer. Unidirectionally reinforced preforms were wound and compression moulded to plates. Flexural tests were conducted to analyse the mechanical behaviour. Additionally the fibre volume fraction was determined to relate fibre content to material properties.

Overall, the study proves the feasibility of manufacturing thermoplastic composite tapes using post-consumer and post-industrial recyclates. Flexural properties and interlaminar shear strength are at the same order of magnitude as the virgin polymer. The results indicate the potential of recycled polymers for manufacturing cost-efficient and sustainable tape without a loss of properties.