Enhancing Compatibility and Performance of Biobased BEE/PLA Composites: A Combined Molecular Dynamics and Experimental Approach

With the increasing depletion of petroleum resources, the application of renewable resources to fully or partially replace petrochemicals in preparing biobased materials has become a trend in the development of new materials. Biobased engineered elastomers (BEEs), prepared by biofermentation or chemical synthesis, combine biodegradability with tunable mechanical properties, making them an ideal alternative to synthetic rubber. Polylactic acid (PLA), a novel biodegradable polymer, is mainly derived from starch-rich biomass such as maize, sugar beets, sugar cane, cassava, and straw. This study focuses on designing high-performance composites using fully degradable PLA and BEE. Based on the coarse-grained simulation method in molecular dynamics simulation, the microscopic phase structure evolution law and its intrinsic correlation with compatibility upon adding a high-molecular-weight compatibilizer (HCMP) to the BEE/PLA composites were systematically investigated, and the comprehensive performance of the composites, including dispersion, chain dynamics, and mechanics, was analyzed. Furthermore, epoxidized soybean oil (ESO) was selected as the HCMP to enhance the capacity of the composites through its ring-opening reaction and cross-linking of chemical bonds. The capacity enhancement effect was evaluated via a thermal analysis test and mechanical test. This work provides a comprehensive analysis of the effect of high-molecular-weight compatibilizers on the compatibility and overall performance of BEE/PLA composites, combining molecular dynamics simulations with experiments. It offers a theoretical basis for the design of high-performance biobased composites and proposes a novel way for investigating the interfaces of biobased composites.