Processing of PC/LCP in situ composites by closed-loop injection molding

Abstract Processing of an in situ composite of PC/LCP was studied using an adaptive closed-loop controlled injection-molding machine. A model system (PC Calibre 300 with 15 wt.% of LCP Vectra A950) was injection molded at a temperature range of 280–320 °C with an injection speed ranging from 12 to 130 mm/s. The injection temperature was found to be a primary factor affecting mechanical properties of the PC/LCP in situ composites. Lower injection temperature effectively improves the tensile and impact strength. Experimental results showed that increasing injection speed improved elastic modulus and impact strength; however, speeds higher than ∼50 mm/s provided little further improvement. A finite element simulation was used to assist the understanding of the processing effects on LCP fibrillation which is crucial for LCP reinforced composites. Lower injection temperature and moderate injection speed were found to be desirable for the optimizing the processing of the in situ composite.