Transesterification of sago starch and waste palm cooking oil in densified CO₂

In this work, the synthesis of biodegradable and yet renewable thermoplastics materials through a transesterification reaction of sago starch and waste palm cooking oil (WPO) in densified CO₂ as the solvent is reported. The aim of this research is to investigate the potential used of sago starch and WPO as raw materials in the thermoplastics starch synthesis. The starch esters was successfully synthesized using sago starch and WPO as reagent in densified CO₂ as shown from the presence of carbonyl group (C=O, 1743 cm^-1) in the FT-IR spectra coupled with the presence of the proton (¹H-NMR) of the fatty acid in the starch backbone (0.8 - 2 ppm). The product crystallinity decreases as shown in XRD results and resulting with a change in the thermal properties (melting and crystalline temperature) of the products. In addition, the products show a different granular morphology and a higher hydrophobicity compared with native sago starch. This research shows the potential used of sago starch and WPO in the thermoplastics starch synthesis and opens a new perspective on the product application.