Facile Strategy to Construct Particle‐Reinforced Thermoplastic Starch Bioplastics by Lactic Acid and Various Anhydrides via Reactive Extrusion

ABSTRACT In this study, we developed a strategy to produce degradable particle‐reinforced thermoplastic starch (TPS) via reactive extrusion using only lactic acid, maleic anhydride, succinic anhydride, and natural starch. The effects of varying the ratios of maleic anhydride to succinic anhydride on the molecular structure, mechanical properties, cross‐sectional morphology, crystallization behavior, water resistance, and soil burial degradation of TPS were systematically evaluated. The addition of succinic anhydride induced the formation of distinct spherical particles in the TPS cross‐section, thereby significantly enhancing the performance of the material. When the succinic anhydride content reached 14.5 wt%, the tensile strength of TPS increased to 5.54 MPa—approximately 30× higher than that of TPS without succinic anhydride, while maintaining a favorable elongation at break of 81%. Furthermore, a reduction in surface energy was observed, leading to an increase in the water contact angle from 42.6° to 75.2°. The material also demonstrated rapid degradation, with a mass loss of 85.5% after 40 d of soil burial, surpassing the degradation rates of commercial biodegradable polymers such as polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polybutylene succinate (PBS). Therefore, this method offers a promising approach for simultaneously improving the mechanical properties, hydrophobicity, and biodegradability of TPS, with potential applications in food packaging and agricultural mulch films.