Epoxidized Camelina Oil as a Renewable Plasticizer to Develop Highly Toughened and Flexible Polylactic Acid Films

Abstract

This study investigates the influence of epoxidized camelina oil (ECO) as a plasticizer on the on the thermal behavior, mechanical performance, and morphological features of polylactic acid (PLA). ECO was incorporated into PLA at 5%, 10%, and 15% by weight, and its effect on elongation at break, impact resistance, modulus, and fracture behavior was evaluated. Nuclear Magnetic Resonance (NMR) spectroscopy confirmed the successful epoxidation of camelina oil, with the disappearance of olefinic proton signals and the appearance of oxirane group signals, validating the high degree of functionalization. Similarly, Fourier-transform infrared (FTIR) spectroscopy confirmed the conversion of double bonds into epoxide groups through the appearance of oxirane peaks and the disappearance of -C=C-H stretching vibrations, along with shifts in PLA carbonyl peaks, indicating hydrogen bonding and strong intermolecular interactions.Mechanical testing showed that addition of 10% ECO significantly enhanced the material properties, with a 1680% increase in elongation at break and a 24% improvement in impact strength compared to neat PLA, indicating substantial improvements in flexibility and toughness. SEM micrographs of tensile and impact fracture surfaces confirmed the transition from brittle to ductile failure with increasing ECO content, showing rougher surfaces, localized plastic deformation, and reduced crack propagation. Thermal analysis demonstrated a reduction in glass transition temperature with ECO addition, further validating its role as a plasticizer. This study demonstrates that ECO effectively tailors the properties of PLA, making it suitable for applications 2 requiring improved ductility, toughness, and energy absorption, such as packaging and biomedical materials.