Enhanced Soil Burial Degradation of Poly(L‐Lactide) by Blending With Poly(Ether‐ Block ‐Amide)

ABSTRACT Plastic pollution is a significant environmental issue, and poly(L‐lactide) (PLLA) is one of the most common biodegradable polymers that meets current environmental protection needs. However, enhancing its degradation rate in soil remains a continuing challenge. Herein, we mainly investigate the phase morphology evolution, mass loss, molecular weight loss, mechanical properties, thermodynamic properties, and molecular structure changes during the soil burial degradation of PLLA/poly(ether‐ block ‐amide) (PEBA) blends. After 90 days of soil burial degradation, the mass loss of PLLA/PEBA (80/20) blend and pure PLLA is 17.3% and 2.3%, the weight‐average molecular weight loss is 24.7% and 15.8%, and the tensile strength decreases by 75.6% and 32.2%, respectively, suggesting a faster soil burial degradation rate of the blend. The enhanced degradation rate is attributed to the existence of phase interfaces, which is beneficial to the water absorption and the attack of microorganisms. Soil burial degradation primarily occurs in the amorphous regions of PLLA, leading to an increase in the relative content of crystalline regions. The molecular structure changes reveal that the mechanism of soil burial degradation of PLLA mainly involves random chain scission of the ester groups on the backbones.