Session 7

Resource efficiency of wood-plastic composites
Philipp F. Sommerhuber
Johann Heinrich von Thünen-Institut, Germany

In the drive towards a sustainable bioeconomy, there is growing interest in the development of composite materials made of plastics compounded with wood particles, known as wood-plastic composites (WPC). The main use for WPC is as outdoor decking material. The market share of WPC decking compared to solid wood decking is small, but due to their promoted customer-friendliness in the use stage, WPC decking are likely to increase their share on the outdoor decking market. New products may soon be introduced to new markets as injection moulding and 3D printing of semi-finished WPC compounds or filaments are currently in an early stage.
Recycling of post-consumer materials is promoted by political strategies and concepts, such as the European Bioeconomy Strategy and the Circular Economy to ensure a sustainable resource supply in the context of resource efficiency. The goal of the research project was to identify resource efficiency potentials of WPC, in terms of the projected increase in WPC consumption and the resulting rise in post-consumer WPC. The focus was on characterizing WPC produced from secondary materials from specific waste streams as well as assessing the environmental parameters of the product and end-of-life (EoL) stages of WPC. An extensive selection of methods was chosen comprising material flow and economic analysis, physical characterization of laboratory scaled WPC specimens, and life cycle assessment (LCA). Application considerations in context of normative standards and policy frameworks completed the holistic approach to be able to identify secondary material substitution potentials and an environmentally sound EoL treatment.