In this study, potato starch (PS) was physically mixed with low-density polyethylene (LDPE) through twin screw extruder to form LDPE/PS composites. Glycerol was added to the mixture as a plasticizer to increase the compatibility of PS and LDPE, which subsequently reduced the brittleness of the composite. The effect of thermoplastic potato starch (TPS) content and two different compatibilizers on the melt flow index (MFI), mechanical properties, morphology, thermal properties, and biodegradability of LDPE/TPS composites were investigated. The results show that the MFI of LDPE/TPS composite with or without compatibilizer decreased as the content of TPS increased. The mechanical properties such as tensile modulus, flexural strength, and modulus of the uncompatibilized composites begin to increase, but the tensile strength and impact strength gradually decrease as the TPS content increases. The addition of compatibilizer further enhances the mechanical properties of the composite. Morphological observations have shown that compatibilized composites can form a good bond between TPS and LDPE, and that starch particles are evenly dispersed in the polymer matrix. In addition, DSC, thermal stability, and biodegradability were performed for dissimilar LDPE/TPS composites. Besides, water absorption of LDPE/TPS composites was reduced through the addition of compatibilizers.
