Enhancing Thermo-mechanical Properties of Thermoplastic Starch/Natural Rubber Blends Through the Synergistic Combination of PEG and Modified Natural Rubber

This study focuses on enhancing the mechanical and thermal properties of thermoplastic starch (TPS) and natural rubber (NR) blends by incorporating polyethylene glycol (PEG2000) and various types of modified natural rubbers, including epoxidized natural rubber (ENR50), poly (methyl methacrylate)-grafted natural rubber (NR-g-PMMA), and poly (butyl methacrylate)-grafted natural rubber (NR-g-PBMA). The influence of the TPS/NR blend ratio, PEG content, and type of modified NR on the properties of the blends was investigated, along with their water absorption and biodegradation. Increased ductile properties were achieved by adding pure and modified NR. Among the series of 90:10 TPS/modified NR blends by weight, the highest toughness (1,628 MJ/m3) was observed when the blend was formulated from ENR50 with 1.0 wt% of PEG. The water absorption of TPS/NR blends was lower than that of TPS but still exhibited a high-water absorption rate compared to the other conventional polymers. Biodegradation tests confirmed the biodegradation capability of TPS/NR blends, and more than 95% of the tested samples were biodegraded in soil within 120 days. These sustainable and eco-friendly TPS/NR blends could be potential materials for single or short-term use products, such as plant nursery pots and other disposable packaging.