Drying Effect on Mechanical Properties of Bio-nanocomposite Films Fabricated from Self-assembled Cellulose Nanocrystals into Potato Starch

Abstract

Composites films with higher mechanical properties from naturally occurring degradable materials are of present demand to achieve goals of sustainable development. Interaction within composite constituents during drying controls mechanical properties. Here, bio-nanocomposites films were first prepared from cellulose nanocrystals synthesized from jute fibres and extracted potato starch with the same chemical formulations. The filler, nanocrystals consist of nanorod-like cellulose particles obtained as an aqueous suspension by sulfuric acid (H2SO4) hydrolysis of jute fibres and the matrix was prepared by plasticization of potato starch after disruption of starch granules with water and glycerin. Nanocomposite films were obtained by casting the homogeneous aqueous suspension at 95oC and followed by natural drying (atmospheric drying, 25oC) and oven drying at 40oC. The thickness of the bio-nanocomposites film about 250 μm was controlled by using a 2 mm thick structural glass frame. It is revealed that with increasing the percentage of cellulose nanocrystals in composite films, mechanical properties corresponding to tensile strength and Young’s modulus were increased significantly. The film containing the highest quantity of cellulose nanocrystals (20% w/w of starch) revealed better properties in case of natural drying (tensile strength 84.2 MPa, Young’s modulus 0.563 GPa, elongation at break 27%) than the film properties (tensile strength 35.2 MPa, Young’s modulus 0.423 GPa, elongation at break 20%) of oven drying.