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

Abstract 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 μm 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.