Recycling of a Cyclic Thermoplastic Composite Material by Injection and Compression Molding

Abstract

One of the primary projected advantages of the new cyclic thermoplastic- based composites, in addition to their ability to be processed by liquid composite molding, is their potential "recyclability." This paper describes a first attempt to prove the technical feasibility of recycling a cyclic polycarbonate-matrix continuous-glass-fiber composite by two common processes: compression molding and injection molding. The results are somewhat mixed but still encouraging. Parts were reprocessed from ground-up continuous-fiber composites by both injection molding and compression molding. The effects of environmental exposure (water and ethylene glycol) on the composite prior to recycling were also investigated. The injection molded parts exhibited excellent mechanical properties, in some cases exceeding those of the analogous commercially available injection molding grade. The compression molded recycled material, however, showed very poor tensile properties, but its impact properties compared well to comparable commercial materials. The mixed performance of the compression molded material was characterized by microstructural inhomogeneity and matrix microcracks thought to be due to processing deficiencies. Work continues toward improving the quality of these cyclic thermoplastic materials and the recycling processes.