pH Responsive Properties of Methyl Red/PVA Polymers for Smart Food Packaging Applications

Abstract

Responsive polymers in particular have gained increasing interest during the last decades due to their unique properties. Their Ability to exhibit sharp and reversible changes in response to environmental pH condition have made them suitable for various applications. The pH responsive polymeric materials are being developed by the researcher in the recent year for the improvement of food safety issue in the packaging materials. In this study organic methyl red (MR) dye is used as a pH indicator induced with polyvinyl alcohol (PVA) films prepared by solution casting method. The prepared samples were characterized for microstructural, morphological, mechanical, water absorption and pH responsive properties using various analytical techniques. The XRD analysis has shown better crystallinity property which is in good agreement with the mechanical strength of the material. The morphological studies have shown homogeneous dispersion of MR on PVA matrix and change in the morphology of the MR/PVA polymer composites after acid treatment. The MR/PVA films were treated with rotten papaya fruit and change occurred in the samples were identified using UV-vis spectrometric analysis. The prepared MR/PVA pH-responsive polymers have shown good pH reactivity in the range of pH 4.5 to 6.5. Overall, the prepared samples have good pH responsive properties with additional qualities like good optical, structural, and mechanical characteristics.