A new life for thermoset composite end-of-life components Some plastic or polymer-based composite materials are not easily recycled. Scientists proved the technical feasibility of a new process to retrieve fibres and chemicals from old boats and cars. Industrial Technologies © Thinkstock Environmental legislation requires industry to recycle production waste and end-of-life products rather than disposing of them in landfills. The European composites industry has been actively seeking ways to meet requirements for doing this. Composites consisting of two or more materials often take the form of a resin matrix reinforced by fibres. Prior to the EU-funded project 'Recycling thermoset composites of the SST' (Eurecomp), there was no satisfactory treatment solution for so-called thermoset composites that cannot be melted once they set into cross-linked three-dimensional (3D) form. Burning is basically a disposal rather than a recycling route, yielding heat but generating polluting emissions. Mechanical breakdown leads to the recovery of only low-value reinforcements. Scientists initiated Eurecomp to develop recycling technology to recover from the surface transport industry products of the highest possible commercial value for sustainable surface transport (SST). The Eurecomp team identified production waste, end-of-life boats and vehicles to be the main sources of composite waste in Europe. Researchers adapted the physicochemical separation and recovery process called solvolysis. They built a laboratory prototype solvolysis reactor, identified main process parameters of interest, and set to work to identify the range of parameters leading to the best recovery of desired products. Preliminary results enabled identification of recovered components as well as testing of their properties to determine whether or not interesting materials were present and if they could be reused. During the second phase of the project, a large-scale prototype reactor was built. Solvolysis trials were initiated using parameters defined in preliminary tests and modified according to need with the new reactor. Scientists successfully recovered mineral fibres to be reused as reinforcement in new composites and small molecules from the organic phase (polymer matrix) to be used by the chemical industry. A life-cycle assessment (LCA) highlighted areas for optimisation to achieve economically feasible industrial upscaling. Eurecomp demonstrated the technical feasibility of using state-of-the-art solvolysis to obtain useful fibres and chemicals from thermoset composite waste. Commercialisation should have important impact on costs for both the composites industry and consumers of related products, as well as for the environment.
