Value Addition of Waste Cotton: Effect of Nanofibrillated Cellulose on EVA/EVOH Toughened Polylactic Acid System

Abstract

The development of bionanocomposites is a promising approach in the current scenario with the urge to maintain environmental sustainability. The present study investigates the effect of nanocellulose on different properties of EVA/EVOH toughened Polylactic acid (PLA). Nanocellulose was isolated from waste cotton via an environmental friendly technique called steam explosion. Nanocellulose filled toughened PLA was prepared via melt mixing technique using twin screw extruder followed by injection molding. Prepared bionanocomposites were characterised by scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis etc. The addition of nanofibrillated cellulose up to 2 wt% retained the tensile strength of PLA/EVA/EVOH ternary blend systems whereas further weight loadings decreased the tensile strength significantly. Also, the addition of nanocellulose up to 2 wt% loading increased the modulus compared to PLA. The addition of nanofibrillated cellulose increased the stiffness of the composite. The percentage elongation at break showed 214% increase in the case of PLA/EVA/EVOH/NC 2 system in comparison to virgin PLA due to the plasticisation effect of EVA/EVOH together with the strong interactions of hydroxyl groups of nanocellulose. The impact strength was increased up to 89% by the addition of 2 wt% of nanocellulose. DSC studies revealed that the crystallization temperature decreased by the addition of nanocellulose up to 2 wt% in PLA matrix. This means that the nanocellulose acted as a nucleating agent such that it initiates crystallization phenomenon at a lower Tcc. The prepared bionanocomposite holds significant potential for sustainable PLA based packaging solutions.