Surface functionalization of extracted nanosilica from rice husk for augmenting mechanical and optical properties of synthesized LDPE-Starch biodegradable film

Abstract

Abstract Nanosilica extracted from rice husk was functionalised using 3-aminopropyltrimethoxysilane inorder to improve its binding with hydrophobic low density polyethylene. LDPE/starch biodegradable blended films were mechanically and optically enhanced by the incorporation of this surface modified hydrophobic nanosilica (contact angle = 97°) into its matrix in comparison to pure nanosilica blended films of the same composition. The produced films before and after degradation (under garden soil and vegetable waste) were subjected to various mechanical (tensile, tear, Young's modulus and stiffness), thermal (TGA, MFI), morphological (SEM,TEM), structural (XRD) and degradation (weight loss, haze, reduction in load at break and transmittance) quantifications. The microstructure and the mechanical testing revealed that the composition of 80:20 of LDPE:starch blend containing 1.5% modified nanosilica (size 65 nm, surface area of 162.23 m2/g) showed an uniform homogenised blend having the highest tensile and tear strength of 10.03 MPa and 155.5 N/mm respectively. At 2.5% nanosilica content in the matrix, the maximum value of Young's modulus, stiffness and weight loss (540 days in garden soil) of 582.76 MPa, 33654.62 N/m and 17.56% respectively could be achieved. The weight loss value followed a first order reaction kinetics with an increase in degradation rate constant with increase in modified nanofiller content.