Thermal behaviour and interactions of cassava starch filled with glycerol plasticized polyvinyl alcohol blends

Abstract

Thermal behaviour and interactions of glycerol plasticized polyvinyl alcohol (PVOH)–cassava starch (CSS) blended films were analysed using thermogravimetry and differential scanning calorimetry methods. The outcomes showed that addition of glycerol has reduced the onset and end-point melting temperatures of the blended films. Samples with 30 and 40 wt.% of PVOH–glycerol blended with CSS exhibited experimental enthalpy of melting (ΔHm) lower than theoretical enthalpy of melting (ΔHmi). Meanwhile, the thermogravimetry degradation of the PVOH–glycerol–cassava starch can be divided into three phases, whereby phase 1 is the vaporization of volatiles, phase 2 is the rapid decomposition/dehydration and elimination of degradants and phase 3 is the formation of carbonaceous residues. These samples have thermogravimetry degradation activation energy (Ea) higher than their original components. For instance, 20 wt.% of PVOH–glycerol blended with CSS has a Ea which is 6.36 and 4.07 times higher than glycerol plasticized PVOH and CSS, respectively. Blending of PVOH–glycerol and CSS are favorable to produce biodegradable compounds resist to thermal attacks.