Epoxidized safflower oil: Synthesis and evaluation of its performance as bioplasticizer for polylactic acid films

There is an emerging trend towards the utilization of biobased polymer formulation for massive applications like food packaging due to environmental concerns. Polylactic acid (PLA), a significant biopolymer, has faced limitations in industrial applications due to its brittleness and poor ductility. To overcome these drawbacks, bio-friendly oils have been employed as plasticizers, to ameliorate overall attributes and expand their use as a potential flexible packaging material. In this work, Safflower oil (SFO) was successfully epoxidized (ESFO) using an in-situ Prilezhaev reaction. 1 H NMR and FTIR analysis indicated that the optimal conditions were a temperature of 70 °C and a residence time of 30 min, resulting in a remarkable maximum selectivity of 96 %. Further, SFO and ESFO modified PLA films were obtained by melt blending and cast film extrusion. The effect of oils on structural, mechanical and thermal properties of PLA was examined. Morphological analysis revealed a smoother surface along with improved thermal stability, moisture barrier, and hydrophobicity for PLA-ESFO (5 phr) films. Additionally, tensile properties emphasized the significant improvement in ductile properties for both the oils, particularly marked in 5 phr ESFO-based films, where 21 folds improved than neat PLA without compromising tensile strength and modulus. Therefore, epoxidized safflower oil exerted plasticization, encouraging the likelihood of PLA as a biodegradable packaging material. • Epoxidation of SFO using Prilezheav reaction with maximum selectivity of 96 % for 30 min reaction. • ESFO have been employed as a plasticizer for polylactic acid films to contribute to sustainable development goals. • Modification of PLA with SFO and ESFO was carried out by melt blending and cast film extrusion. • PLA with 10 phr of oils has showed intensified increment of elongation at break of 2376 % greater than pure PLA. • Thermal stability was significantly enhanced for PLA/ESFO films, thus ESFO could also serves as thermal stabilizer.