Effect of cold caustic extraction on the properties of lignocellulosic nanocrystals (LCNCs) and lignocellulosic nanofibriles (LCNFs) produced from monoethanolamine (MEA) pulp of bagasse

In this study, the production of lignocellulosic nanocrystal (LCNC) and lignocellulosic nanofibril (LCNF) was investigated using cold caustic extraction (CCE) as an alkaline pre-treatment on monoethanolamine (MEA) pulp of bagasse. CCE treatment can improve the production efficiency, and thermal and morphological properties of LCNCs and LCNFs with cellulose purification, hemicelluloses extraction as well as fiber swelling. The optimum cold caustic extraction treatment on the pulp was obtained using 10 % sodium hydroxide at 20 ° C for 1 hour. LCNCs were produced by acid hydrolysis method using 64 % sulfuric acid, a retention time of 45 min. at 45 ° C. LCNFs were prepared by a microfluidizer passing through three chambers with diameters of 50, 100, and 200 μm for 2, 4, and 6 hours, respectively. SEM images showed that cold caustic extraction reduced the average diameters of LCNCs from 66.91 nm to 34.63 nm and the average diameter of LCNFs from 27.13 to 17.35 nm. The results of XRD also showed that after CCE treatment, the crystallinity index of LCNCs and LCNFs increased from 87.31 to 93.84 % and from 81.68 to 83.47 %, respectively. The results obtained from TGA and DTG thermal analyses show that cold caustic extraction treatment increases the thermal stability of the nanolignocelluloses. FTIR results confirmed that the amount of hemicelluloses and lignin was reduced from the fiber surface after cold caustic extraction treatment. Generally, the results show the improvement and modification of the properties of nanolignocelluloses using a simple and fast pretreatment method.