Study of blends based on poly (lactic acid) and vegetable oils

Abstract

Due to the high brittleness of the poly (lactic acid) (PLA), the main purpose of this work is to obtain a more ductile material than neat PLA, and the subsequent characterization by different techniques. In order to plasticize neat PLA, some plasticizers from renewable resources, such as non-epoxidized and epoxidized and soybean oils, have been used. Neat PLA has been plasticized with 20 wt% of plasticizers and the properties of different blends have been studied. Impact test results have showed that PLA became more ductile with the addition of vegetable oils. Furthermore, PLA/epoxidized vegetable oil blends showed higher tensile and impact strength values than that for blends plasticized with non-epoxidized oils. Fourier transform infrared spectroscopy (FTIR) technique has showed that the band related to the epoxy group did not completely disappear in the spectra of PLA/epoxidized vegetal oil suggesting an incomplete reaction between the epoxy group of epoxidized vegetable oils and the functional groups of PLA. Finally, by differential scanning calorimetry (DSC) technique has observed that after the addition of vegetable oils, both the glass transition temperature (Tg) and the cold crystallization temperature (Tcc) values of the neat poly (lactic acid) were decreased considerably.