Poly (propylene carbonate)-based in situ nanofibrillar biocomposites with enhanced miscibility, dynamic mechanical properties, rheological behavior and extrusion foaming ability

Poly (propylene carbonate) (PPC) foams have attracted more attention in recent years because of their biodegradability and the fixation of carbon dioxide (CO2). Despite their many attractive features, a relatively low decomposition temperature, a low glass transition temperature (Tg), weak mechanical properties and poor melt strength of PPC matrix limited their commercial applications as a viable candidate for conventional plastics. In this study, we report a facile, effective, low-cost and eco-friendly approach for the preparation of PPC/PBS/PTFE ternary in situ nano-fibrillar biocomposites to significantly improve the strength and foaming ability of PPC without sacrificing their excellent biodegradability. The in situ nano-fibrillar networks in the PPC/PBS matrix demonstrated that significant reinforcement effects on the matrix strength, dynamic mechanical and rheological properties at low PTFE contents. In contrast to pure PPC, Tg increased by 15 °C, 851% higher in storage modulus and 17 times enhancement in the initial viscosity of biocomposites. In continues extrusion foaming process, the PBS domains and PTFE nano-fibrils network generated remarkable synergistic effects on the foaming behavior, resulted in higher cell densities (two orders of magnitude), compressive modulus (30 times) and compressive strength (20 times) of PPC/PBS/PTFE (70/30/3) biocomposites.