Starch plasticized with glycerol from biodiesel and polypropylene blends

Plastics have been used in short-life products, which have presented harmful consequences for the nature, due to the low degradation rate reached by the most common polyolefins, such as the polypropylene. By this way, the incorporation of pro-oxidants has been shown nice results to the bio-assimilation of the common polymers. The aim of this study is to evaluate the mechanical and thermal properties of pure iPP, plasticized starch (TPS) with biodiesel glycerol (TPS(Bio)) or commercial glycerol (TPS(Com)), and their blends (iPP/TPS(Plas)). TPS was plasticized in proportions of 80/20 (wt starch/wt glycerin). Blends of iPP/TPS(Plas) were obtained by extrusion in the following composition rates: 95/5, 90/10, 80/20, and 70/30 of modified PP/TPS(Plas). Mechanical properties, calorimetric analysis, and thermogravimetric data were obtained, and biodegradation under simulated soil was performed. It can be verified that there were no meaningful variation induced by the incorporation of TPS(Plas) on the melting temperature on the blends, when compared to pure iPP. The addition of TPS(Plas) caused an increasing on the crystallinity of iPP, mainly for the compositions 90/10 and 80/20 of iPP/TPS(Plas), probably due a morphological alteration such as crosslinking, which may have modified the molecular arrangement of the iPP macromolecules by the presence of glycerol, which was also indicated by mechanical evaluations. (AU)