Effect of Chemical Modification of Melicoccus Bijugatus Jacq Starch on the Fabrication of Poly(lactic acid)/Starch Films

Abstract

This study presents the characteristics resulting from the modification of the Melicococcus bijugatus jacq (huaya) with hexamethyl diisocyanate (HDI) and epoxidized avocado oil (AO) by the one‐step method within situ formation of peracetic acid (PA). HDI‐modified huaya starch and epoxidized AO present chemical characteristics that, according to the literature, improve the compatibility between polylactic acid (PLA) and starch when used to prepare biodegradable films according to the proposed reaction mechanism. The FTIR analysis confirmed that the grafting reaction of HDI onto the surfaces of the huaya starch granules and the epoxidation of the avocado oil took place. Peaks corresponding to vibrations of ‐NCO and ‐NH functional groups and vibrations of epoxy groups are present. The degradation profiles of the thermogravimetric analysis showed that more energy is required to initiate degradation after modification of the compounds. Scanning electron microscopy results showed effects on the huaya starch granules′ surface after the modification with HDI and a change in size. These results suggest compatibilization between the carbonyl groups, like those in the polylactic acid, the epoxy groups of the modified oil, and the isocyanate groups of the functionalized starch.