Novel Synthesis and Characterization of Cellulose Nanocrystals Composites Fabricated from Rice Husks

Abstract

Nanotechnology has shown interest in the utilization of agricultural byproducts as a source for nanostructured materials. Due to their distinctive chemical, thermal, mechanical, morphological, optical, and electrical properties, cellulose nanocrystals (CNCs) have often found utility in a variety of fields. Using sulphuric acid with a 64% weight-to-weight ratio, we managed to extract CNCs chemically from rice husks for the study and examined the effects of varying the hydrolysis period and synthesized composites on optical and thermal characteristics. The usual procedure for preparation was followed, but set the hydrolysis time for 40, 60 and 90 minutes, and also varied temperature at 40˚C, 45˚C and 50˚C. Tonic water and silver nanoparticles were used to synthesize the composites at different ratios. The samples were characterized using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. From the results of this study, maximum absorption is observed to shift to shorter wavelengths with an increase in temperature, and the peak absorbance (maximum wavelength) generally increased with hydrolysis time at all three temperatures. The FTIR spectrum of cellulose nanocrystals (CNCs), AgNPs and their composites exhibited distinctive absorption bands indicative of their molecular structure and chemical composition. From the TGA findings, the two composites had a relatively low thermal stability, hence restricting their application to a fixed temperature and below. Additionally, this property makes the composite easily formable into intricate designs, which is ideal for use in optical components and sensors. The low melting point also facilitates recycling and reprocessing, enhancing sustainability by enabling the reuse of the material in various applications. Moreover, the composite’s sensitivity to temperature can be useful in temperature-sensing applications, where changes in its properties at lower temperatures can provide valuable optical feedback.