Improving the foaming and mechanical properties of the in situ microfiber-reinforced polyethylene terephthalate/polypropylene composites through compatibilization

The in situ microfiber-reinforced polyethylene terephthalate/isotactic polypropylene (15/85, w/w) composite (PET/iPP MRC) was successfully obtained through the micro-nano-laminating co-extrusion by using polypropylene-grafted-glycidyl methacrylate (PP-g-GMA) as a compatibilizer. The effect of the compatibilizer on the rheological behavior, micromorphology of PET/iPP MRC, foaming capability and the mechanical properties of foamed PET/iPP MRC was investigated. Extensional rheology measurement revealed the strain hardening of PET/iPP MRC is more obviously than iPP and with compatibilizer added. Scanning electron microscope observation indicated that the introduction of PP-g-GMA compatibilizer can improve the compatibility between PET and PP and subsequently lead to the decrease of diameter of PET microfibers. In addition, the incorporating of PP-g-GMA compatibilizer can also decrease the diameter and enhance the cell density of PET/iPP MRC cell. Both the tensile strength and the impact strength of the PET/iPP MRC foam are higher than that of the iPP foam, and improved with the compatibilizer added.