On the use of acrylated epoxidized soybean oil as a reactive compatibilizer in injection‐molded compostable pieces consisting of polylactide filled with orange peel flour

Novel green composites made of polylactide (PLA) and orange peel flour (OPF) were melt‐compounded using twin‐screw extrusion and shaped into pieces by injection molding. Orange peel, a major by‐product of the juice industry, was first ground to flour and then incorporated as a lignocellulosic filler into the biopolymer at 10, 20 and 30 wt%. Since both components of the green composite presented low compatibility, the resultant injection‐molded pieces showed poor ductility and impaired thermomechanical performance. As a new bio‐based reactive compatibilizer, acrylated epoxidized soybean oil (AESO) was added at five parts per hundred resin to the PLA/OPF formulations during the extrusion process. The addition of AESO increased the filler–biopolymer adhesion and led to compostable green composite pieces with improved physical properties. The enhancement achieved was related to a dual effect of plasticization and melt grafting of the OPF particles onto the PLA chains provided by the multiple acrylate and epoxy groups present in AESO. The use of multi‐functionalized vegetable oils to improve the performance of green composites certainly opens up new opportunities for the expansion of fully bio‐based and biodegradable materials that are partially obtained from agro‐food waste.