Chemical-Mechanical Hydrolysis Technique of Modified Thermoplastic Starch for Better Mechanical Performance

The effects of chemical-mechanical hydrolysis on the properties of thermoplastic starch (TPS) were studied. In the presence of citric acid (CATPS) and glycerol (GTPS) along with mechanical hydrolysis, a native starch granule was transformed into a continuous phase as shown by scanning electron microscope (SEM). As shown by thermogravimetric analysis (TGA), the improvement in thermal stability confirmed that the addition of citric acid along with mechanical hydrolysis enhanced the adhesion between glycerol, citric acid and starch. It was proven by Fourier transform infrared (FTIR) spectroscopy, that citric acid form stronger hydrogen bonding than glycerol. Strong hydrogen bond formation induced the improvement in mechanical properties of GTPS. Tensile strength of citric acid modified TPS with 2% citric acid (CATPS) higher than GTPS because citric acid improved the interaction of starch molecule and slippage of starch chain.