Effect of hydrolysis agitation and suspension drying temperature on the synthesis of crystalline cellulose from jute fiber

Abstract

Proper synthesis mechanism and control over the synthesis process are essential for obtaining high-purity crystalline celluloses (CCs). In this research, CCs were synthesized from jute-derived cellulose through an acid hydrolysis process. The objective of the study was to analyze the effects of the hydrolysis stirring rate and suspension drying temperature on the crystallinity, crystal size and nature of CCs. FTIR analysis confirmed the optimal condition for extracting cellulose free from hemicellulose and lignin, that is for C₃ (cellulose extracted by 18 % NaOH treatment) and also provided evidence of crystallinity and purity of cellulose. Higher alkali affected the yield of cellulose negatively. At a fixed hydrolysis concentration of 50 %, continuous agitation resulted in cellulose nanocrystals (CNCs), while occasional agitation produced cellulose microfibers (CMFs). XRD analysis revealed that CNCs exhibited higher crystallinity than CMFs, with CNC₁ achieving the highest crystallinity of approximately 62.5 %. The SEM confirmed the morphology and dimensions of cellulose, CNCs and CMF, also the agglomeration of CNCs due to their moisture affinity. The drying temperature significantly influenced crystal size, with larger crystals forming at higher temperature (70 °C). TGA-DSC-DTG analyses indicated that, the thermal stability of CCs was somehow compromised, however, CCs retained a higher residue than cellulose at 550 °C.