Thermal decomposition kinetics and properties of grafted barley husk reinforced PVA/starch composite films for packaging applications

Thermal degradation kinetics was performed on thermogravimetric (TGA) curves of crosslinked PVA/starch composite films reinforced with barley husk (BH) and grafted BH (using lauric acid) obtained by heating samples in an inert atmosphere with different heating rates (5, 10, 15 and 20 degrees C/min). The activation energy for composite films was determined using Flynn-Wall-Ozawa (FWO) Kissinger-Akahira-Sunose (KAS), Friedman (FR) and modified Coasts Redfern (CR) methods. The results showed that activation energy for thermal degradation of grafted BH composite film was higher than of BH. Incorporation of grafted BH into crosslinked PVA/starch matrix improved the mechanical performance of the films compared to BH and showed 30 % increase in tensile strength after reinforcement. Grafted BH composite films showed higher barrier properties for light, water vapor and oxygen as required for packaging applications. Biodegradability of the films improved significantly after incorporation of BH into the polymer matrix and showed 70 % degradation after 180 days.