The optimized approach for preparing cellulose nanocrystal: phosphoric acid pretreatment

• Main Authors: Che-Ning Yang, 楊哲寧
• Other Authors: 柯淳涵
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/4s7gmk

碩士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 107 === Cellulose nanocrystals (CNCs) is a renewable and biodegradable materials, traditional approach for preparing CNCs is through sulfuric acid hydrolysis, but it is time-consuming with low yield. In this study, we aim to produce high quality CNCs in efficient way. We prepare four kinds of cellulose feedstocks, including microcrystalline cellulose, bleached pulp, unbleached pulp and α -cellulose, each material was first decrystallized by phosphoric acid pretreatment, follow by sulfuric acid hydrolyzed to prepare cellulose Nanocrystals. The result shows that with phosphoric acid pretreatment, the nanoscale cellulose can be obtained within 7.5 min, particle size was between 10-100 nm with unimodal distribution, which is much efficient than the control group, and as hydrolysis time rising the smaller particle size can be observed. Adding anionic electrolyte increased dispersibility and reduce self-assembly by reducing zeta potential from -9±-0.8 to -20.9±-2.1 mv, which lead to better hydrolysis efficiency. All cellulose after sulfuric acid hydrolysis got massive weight loss due to degrading, cause by glycosidic bond breaking, two stage hydrolysis microcrystalline cellulose after 7.5 min sulfuric acid hydrolysis, molecular weight drop dramatically from 61.68 to 12.82. These result prove that more homogenous cellulose can be acquired by implementing phosphoric acid pretreatment.