Architectural Effects of Biodegradable Block Copolymers on Enhancing PLA/PCL Blend Compatibility: Molecular Dynamics Simulations

We employed molecular dynamics simulations to investigate the efficiency of polylactic acid (PLA)-, poly(caprolactone) (PCL)-, and poly(ethylene glycol) (PEG)-based biodegradable copolymers as compatibilizers in PLA/PCL blends. Di- and triblock copolymers with various block sequences were systematically designed and studied. The findings reveal that the block type and architecture of the copolymers play a crucial role in determining their compatibilization efficiency. Specifically, our unentangled copolymers with PLA blocks at the chain ends, particularly triblock structures, exhibit good localization within both PLA and PCL homopolymer phases. This localization enhances interphase interactions and improves the melt tensile performance of the blends. In contrast, copolymers with PCL blocks at the chain ends, especially triblock architectures, tend to localize preferentially within the PCL phase, leading to less effective compatibilization. These insights could pave the way for the development of tailored compatibilizers to optimize the properties of immiscible polymer blends.