Influence of Bio‐Based Polyurethane Synthesized Using Castor Oil/Polycaprolactone Diol on the Properties of Poly(Lactic Acid), and Its Biodegradability

ABSTRACT In this study, we investigate the overall performance and biodegradation properties of glycidol end‐terminated thermoplastic polyurethanes (PUG)‐based blends using conventional reactive blending with poly(lactic acid). PUG was synthesized using polycaprolactone (PCL) diol and chain extenders, including castor oil, 1,4‐butanediol, and varying glycidol content as a functional group to enhance compatibility with PLA. The blends of different compositions, thermo‐mechanical, rheological, morphological, and biodegradation properties were studied. The FTIR results confirmed the reactive blending, while the rheological studies showed the enhanced structural integrity and elasticity at higher PUG loading. PUG3 blends exhibit superior mechanical properties, especially in the 30% blend ratio, compared to the other formulations (PUG1 and PUG2, which have lower glycidol content), due to the higher glycidol content, which facilitates enhanced reactive blending and interfacial adhesion with PLA. Thermal analysis reveals a reduction in crystallinity and an improvement in thermal stability. However, the biodegradation study reveals that the pristine PLA shows a higher degradation rate compared to the blends, possibly due to the elastomeric PUG reducing the hydrolysis of the ester bond. Therefore, this research demonstrates a novel strategy that integrates bio‐based and glycidol‐functionalized PUG to achieve superior toughness, interfacial compatibility, and thermal resilience in PLA blends, as well as enhanced biodegradation properties, making it a promising candidate for sustainable packaging applications.