Polymer, Vol.76, 25-33, 2015
Understanding the controlled biodegradation of polymers using nanoclays
The main objective of this work is to develop an innovative way to control the biodegradation of polymers using naturally occurring nanoclay to create an eco-friendly method to obliterate polymers instead of incineration. Poly(epsilon-caprolactone) (PCL), poly(lactic acid) (PLA) and polyurethane (PU) have been taken as representative polymers having ester and urethane linkages whose rates of biodegradation are regulated (both increase and decrease) using organically modified nanometer dimension clays in enzyme media. The extent of biodegradation was measured as a function of time using spectroscopic method as well as weight loss measurements. Photographic image and electron microscopy have been employed to verify the controlled biodegradation in enzyme media. Calorimetric and diffraction studies support the synchronized biodegradation as observed through kinetics and morphology. The mechanism of controlled biodegradation has been established by evaluating the depolymerase activity of polymers in different pH environment which in turn was generated in solid phase by incorporating the nanoclays in polymer matrices. Therefore, nanoclays control the biodegradation of different polymers in a definitive time frame. Serine mediated hydrolysis/cleavage by the enzyme has been highlighted and alteration of enzyme configuration under varying pH induced by nanoclays has been projected. Moreover, a model has been proposed for the controlled biodegradation of polymer induced by different nanoclays. (C) 2015 Elsevier Ltd. All rights reserved.