Greener extraction of highly crystalline and thermally stable cellulose micro-fibers from sugarcane bagasse for cellulose nano-fibrils preparation

This study aims to assess Na2CO3 treatment as a potential pre-treatment for extracting cellulose micro-fibers and subsequently cellulose nano-fibrils (CNF) from sugarcane bagasse. For cellulose micro-fibers extraction, Na2CO3 concentration, reaction time, and temperature were critical factors influencing reaction kinetics. It was concluded from statistical analysis of crystallinity index (CrI) that temperature was the most significant factor. Moreover, reaction time and Na2CO3 concentration were minimized while maximizing temperature to get an increase of 33 % and 115.2 % in the CrI and activation energy of thermal degradation, respectively. FTIR analysis of cellulose micro-fibers indicated the removal of hemicellulose and lignin. For the preparation of CNF, ionic liquid (IL) 1-n-butyl-3-methylimidazolium chloride was used. The CNF diameter was in the range of 4–35 nm, and the length was in a few micrometers. Hence Na2CO3 treatment in the combination of IL treatment is an efficient and environmentally friendly approach to valorize sugarcane bagasse into high-value CNF.