Toughness enhancement of polylactide with low amounts of poly (butylene adipate-co-terephthalate) through in situ reactive compatibilization

Polylactide (PLA) was melt blended with low amounts of poly (butylene adipate-co-terephthalate) (PBAT) using a simple reactive extrusion process herein, aiming to address the inherent brittleness of PLA without significantly compromising its stiffness. PLA/PBAT (90/10) blends with a small amount of peroxide (0.02 phr) and a second crosslinker agent triallyl isocyanurate (TAIC) were produced to explore the structure-performance relationship evolution in reactive extrusion. The results showed that the PLA blend with an appropriate amount of TAIC (i.e., 0.3 phr) exhibited a remarkable increase in elongation at break, reaching as high as 96%. The sample with high elongation also demonstrated a high stiffness, boasting a Young's modulus of 2.4 GPa and a yield strength of 43 MPa. It was evident that the combination of enhanced compatibility and optimized homogeneous PBAT phase size of approximately 0.6 mu m worked synergistically to enhance the toughness of PLA. Conversely, higher TAIC contents resulted in over-crosslinking, despite considerable improvements in compatibility. This study offers a versatile, scalable, and practical method to prepare fully biodegradable PLA blends with high toughness. Reactive extrusion of polylactide (PLA)/poly (butylene adipate-co-terephthalate) blends with a high PLA content of 90 wt% enables the production of biodegradable polymeric materials exhibiting enhanced mechanical properties, including an elongation at break of 96%. image