Preparation and Characterization of Thermoplastic Cassava and Sweet Potato Starches

Abstract

Thermoplastics starches are plastics made from renewable resources like plants that are fully bio-based and biodegradable. The aim of this study was to produce and characterize thermoplastic using starches extracted from cassava and sweet potato. The effect of variable amounts of glycerol used as plasticizer and acetic acid used for hydrolysis of the starch polymer were investigated. The intermolecular interaction between the starch and glycerol was ascertained using FT-IR spectroscopy. The biodegradability test conducted on both cassava thermoplastic starch (TPSc) and potato thermoplastic starch (TPSp) were found to lose 36% and 23% respectively of their initial weights after seven days of soil burial. The result showed that as plasticizer concentration increased from 50 to 80%, there was an increase in both moisture and oil uptake but a decrease in water uptake. However, an increase in acetic acid concentration from 2.5% to 7.5% resulted in a decrease in oil uptake, water uptake and moisture uptake of the thermoplastics. Findings in this study reveal increase in the amount of glycerol plasticizer in both thermoplastics increases moisture contents retention however the observed oil uptake and biodegradability properties suggest the thermoplastic starches especially the potato thermoplastic starch is generally suitable for making eco-friendly thermoplastics.