Biodegradable polymers. XI. Spectral, thermal, morphological, and biodegradability properties of environment-friendly green plastics of soy protein modified with thiosemicarbazide

Abstract

The demand for biodegradable polymers produced from renewable natural resources continues to grow as environmental concerns increase. Biodegradable plastics derived from agricultural feedstock are a new generation of materials capable of reducing the environmental impact in terms of energy consumption and greenhouse effect in specific applications to perform as traditional/conventional plastics when in use and are completely biodegradable within a composting cycle through the action of living/micro-organisms. The objective of this study is to examine the potentiality and performance pattern of Soy protein isolate (SPI) resin, modified with various concentrations of thiosemicarbazide (TSC), as a thermoplastic to substitute some conventional petroleum-based plastics. The spectral, thermal, morphological properties and the biodegradability of the modified resin have been investigated. The spectral studies indicate that TSC is not crosslinked with the protein moiety; rather, it acts as a modifier. 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 degradation mechanism has been ascertained on the basis of the kinetic parameters. It is expected that, this environment-friendly, fully biodegradable and sustainable TSC-modified SPI green plastic could be commercially used for making molded products. (c) 2006 Wiley Periodicals, Inc.