Biodegradable polymersPart VI. Biodegradable plastics of soy protein isolate modified with thiourea

Potential alternative to petrochemical polymers, soy protein isolate (SPI), a plentily available, natural biopolymer is chemically modified with thiourea at 2.5, 5, 7.5, 10, 15 and 20 mass/mass% for better processing of plastic as a raw material. From the FTIR studies, it has been ascertained that there is no bonding reaction between SPI and thiourea and it acts as a modifier only. Thermogravimetric analysis of the modified material has been followed using a computer analysis method, LOTUS package, developed by us for assigning the degradation mechanism. A number of equations have been used to evaluate the kinetic parameters. The mechanism of degradation of the biopolymer is explained on the basis of the kinetic analysis.