Enhanced Extrusion Processability of PLA Blends through Rheology Control Using Biodegradable PLA-based Graft Polymers

Owing to the increasing global emphasis on the eco-friendliness of materials, significant progress has been made toward the development of polymer blends containing biodegradable polylactic acid (PLA). Over the past few decades, research on PLA has primarily focused on enhancing its physical properties and processability for advantageous industrial applications. In this study, we leveraged the unique rheological properties of bottlebrush polymers (BBPs) to improve the processability of PLA and verified their applicability as processing aids. Cellulose acetate butyrate (CAB)-based PLA-grafted polymers (CAB-g-PLA) were designed to mimic the characteristics of BBPs. Moreover CAB-g-PLAs were synthesized by grafting PLA onto cellulose-based biodegradable polymers to produce blends with PLA without compromising their biodegradability. The biodegradable CAB-g-PLAs were characterized through GPC, FT-IR spectroscopy, and SEM. The rheological and mechanical properties of the PLA blends with the CAB-g-PLAs were compared by adjusting the molecular weights of the backbone and side-chains of the CAB-g-PLAs. The role of CAB-g-PLAs as processing aids was analyzed by examining the melt tension and drawing resonance phenomena during the extrusion process, demonstrating the improved processability of the PLA blends. Our results facilitate the broader industrial adoption of biodegradable polymers, enabling industries to achieve eco-friendly goals without compromising material performance.