Industrial vegetable oil by-products increase the ductility of polylactide

The use of industrial by-products of the vegetable oil industry as ductility agents of polylactide (PLA) was investigated. Vegetable oil deodorization condensates were melt-blended by twin-screw extrusion up to a maximum inclusion quantity of 20 wt% without preliminary purification. Sample films were obtained by single screw cast extrusion. Compounded PLA films featured largely improved ductility in tensile testing with an elongation at break up to 180 %. The glass transition temperature remained higher than room temperature. The native mixture of molecules contained in the deodorization condensates had superior performance compared to a synthetic mixture of main compounds. The investigation of the correlation between composition of the additives and the ductility of the PLA blends by Principal Component Analysis showed a synergistic effect between fatty acids having a melting point below and beyond the room temperature. Furthermore, a compatibilizing effect of molecules present in the native mixture was evidenced. Oil deodorization condensates, which are a low-priced by-product of the vegetable oil industry, are therefore a very promising biobased and biodegradable additive for improving PLA ductility