Isolation of nanocrystalline cellulose from rice straw and preparation of its biocomposites with chitosan: Physicochemical characterization and evaluation of interfacial compatibility

Abstract

In order to develop high value-added rice straw residue biocomposites, nanocrystalline cellulose (NCC) from rice straw and chitosan (CS) were used as two main raw materials, the CS/NCC biocomposites were prepared by an acid hydrolysis-ultrasonic treatment and blending casting. The physicochemical properties and evaluation of interfacial compatibility on CS/NCC biocomposites were characterized by TEM, ZP analyzer, UV-vis, FTIR, SEM, XRD, TG, DSC, electron mechanical instrument and water absorption testing. The results reveal that a uniform rod-like or filamentary structure of NCC from rice straw, with the width distribution concentrated on the range of 10–15 nm and several hundred nanometers in length, can be effectively obtained by a relatively high ultrasonic power treatment with the same acid hydrolysis conditions. The superior interfacial compatibility of CS/NCC biocomposites with excellent tensile strength can be achieved at 5% NCC addition level due to optimal dispersion of NCC, strong hydrogen bonding and potential electrostatic interactions between CS and NCC. Additionally the thermal stability and water absorption of biocomposites increase, while the transparency rate, elongation at break decrease as the increase of NCC addition amount from 0% to 20%.