Epoxidized canola oil as an environmentally friendly compatibilizer for blending poly(lactic acid) and poly(butylene adipate-co-terephthalate)

Blends of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are biodegradable polymers with opposite, yet complementary, physical and thermal properties. However, PLA and PBAT are immiscible and additives must be introduced to overcome their incompatibility and achieve their full potential as blended polymers. In this work, we describe the use of epoxidized canola oil (ECO) as a novel compatibilizer for PLA and PBAT. ECO was produced and characterized using Attenuated Total Reflectance Fourier-Transform Infrared spectroscopy (ATR-FTIR) and proton nuclear magnetic resonance (1H NMR). ATR-FTIR confirmed the epoxidation reaction, while 1H NMR was used to quantify the alkene-to-epoxy conversion rate. Polymer blends were prepared using a batch mixer and were characterized using ATR-FTIR, 1H NMR, scanning electron microscopy, differential scanning calorimetry, and mechanical analyses. The polymer blends containing ECO demonstrated a significant reduction in the PBAT dispersed phase size and thermal transitions of PLA (glass transition, cold crystallization, and melt temperatures), as well as a significant increase in elongation-at-break while maintaining the same tensile strength and Young’s Modulus.