Effect of different compatibilizers on the final properties of the PLA/PBSA biopolymers-based blend prepared by reactive extrusion

Abstract

It is well known that the research for biopolymers-based materials is crucial in these times where the environmental issues resulting from the plastic industry keep increasing. Poly Lactic Acid (PLA), a biodegradable and bio-based polymer with comparable strength and stiffness to petroleum-based polymers, holds promise as a bio-based material. However, PLA-based materials suffer from limitations, particularly poor toughness characterized by low ductility and impact resistance. To address this challenge, the blending of PLA with PBSA, a polymer known for its high ductility and impact resistance, is explored. However, the resulting blend exhibits immiscibility and low compatibility, leading to poor mechanical properties. Reactive compatibilization is employed as an effective approach to tackle this problem. This process involves mixing the polymers in an extruder while incorporating a reactive agent to improve interactions between PLA and PBSA. In this study, four different compatibilization techniques are evaluated. The first one involves direct compatibilization by simultaneously feeding the polymers with Dicumyl peroxide (DCP), as the reactive agent, into the extruder. The second one follows the same method, but Maleic anhydride (MA) is used as the reactive agent, and the reaction is initiated by DCP. The last two approaches involve preparing maleated polyesters using MA initiated by DCP in a preliminary extrusion process. In one approach, the resulting PLA-g-MA is then utilized as a compatibilizer in the blend during a second extrusion process, replacing a portion of PLA in the blend. In the other approach to compatibilize, PBSA is replaced by PBSA-g-MA in the blend. The effect of the reactive agent’s proportion is also investigated in all the attempts. Injection molding is used to produce specimens for testing. Comprehensive characterization, including thermal, mechanical, and microstructure analysis, is conducted to evaluate the properties of the blends.