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J Polym Environ (2013) 21:930936 DOI 10.1007/s10924-013-0572-4
ORIGINAL PAPER
Preparation and Properties of Propylene Glycol Plasticized Wheat Protein Isolate Novel Green Films
Dani Jagadeesh B. Prem Kumar P. Sudhakara
C. Venkata Prasad A. Varada Rajulu
J. I. Song
Published online: 24 February 2013 Springer Science+Business Media New York 2013
Abstract Novel bio-based green lms were prepared using wheat protein isolate (WPI) by solution casting method using Propylene Glycol as a plasticizer for packaging applications. The effect of the plasticizer content (10, 15, 20 and 25 wt%) on mechanical properties (tensile strength, youngs modulus and % of elongation) was investigated. A thermal degradation and phase transition of the prepared WPI was assessed by means of TGA and DSC analysis. The results showed that the tensile strength and youngs modulus decreased and % of elongation increased with increasing PG content. The ATR-FTIR and SEM were used for structural characterization and morphology of the lms, respectively. FTIR studies reveals that the intensity of the bands corresponding to the amide groups increases with increasing PG content tending to increase proteinPG interactions. Further, the glass transition temperature was decreased and the thermal stability of the WPI was found to be increased by plasticization. The overall thermal stability
of the lms was improved and is attributed to the increase in mobility of the polymer chains.
Keywords Propylene Glycol Plasticizer Wheat protein
isolate (WPI) Eco-friendly materials Mechanical
Properties and packaging applications
Introduction
Since the invention, the use of non-renewable (non-sustainable), oil and petroleum based synthetic polymers has increased signicantly and this continues today. The main problems with synthetic polymers are that they are non-degradable and non-renewable. Currently there has been an increasing interest in development of green polymer lms from renewable resources with a small ecological load and at the end of their life; most of them end up in landlls [1, 2].
Biopolymer lms are generally designed from biological resources such as polysaccharides, proteins, lipids, and their derivatives. Proteins (plants or animal derived) are ideal material for bio-plastics production due to the presence of many polar and non-polar amino acid groups providing a broad spectrum of functional and structural properties [37]. Various researchers have been investigated the lm properties of proteins from soy protein, cotton seed, wheat gluten, pea proteins, maize...