LCA and LCC of a chemical recycling process of waste CF-thermoset composites for the production of novel CF-thermoplastic composites. Open loop and closed loop scenarios

Abstract

The case study presented in this paper is a follow up of a topic already examined in previous studies relating the life cycle assessment (LCA) of a chemical treatment process used to recycle a specific type of carbon fiber (CF) reinforced thermoset composite. In the present study the LCA is coupled with the life cycle cost (LCC) analysis for the economic assessment. Furthermore, the research sought to specify the best available technology for the reuse of the materials recovered through the chemical recycling process. The new LCA results are more reliable and more current than the scenario presented in the previous LCA studies. In the previous scenario the possibility to recover long carbon fibers “ready to use” was considered. This scenario, even if under investigation by the recycling company, is still not possible for technological limitations as the fibers recovered after the chemical process require further treatments before being used in thermoset composite. Consequently, a more feasible technology was investigated and, according to our laboratory research results, one practical way to recycle the CF-thermoset composites is to shred them before the chemical treatment in order to recover shredded CFs and epoxy thermoplastic from cleavable thermosets. These materials can be easily compounded together to manufacture a CF-thermoplastic composite through injection moulding as we demonstrated herein through some laboratory experiments. The LCA and LCC were accounted for the recycling process via solvolysis up to the recovery phase of the epoxy-thermoplastic resin and the short carbon fibers. The paper presents laboratory test results of the remanufacture of the two reclaimed materials for the production of a thermoplastic CF-composite.