Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Chemical and Biochemical Engineering

Supervisor

Charles(Chunbao) Xu

2nd Supervisor

Takashi Kuboki

Joint Supervisor

Abstract

This thesis project aimed to fractionate cornstalk into cellulose and lignin, and utilize the crude cornstalk-derived cellulose for the production of sodium carboxymethyl cellulose and the lignin for the sybthesis of bio-based phenol-formaldehyde resole resins as wood adhesives. In this thesis work, cornstalk was efficiently fractionated into crude cellulose and crude lignin in mixed solvents of acetic acid, formic acid and water at a solid/agent ratio of 1:5 (g/mL) at 80-100 °C for 120-240 min. The best conditions for organosolv fractionation of cornstalk among the test conditions were determined as follows: mixed solvent of acetic acid/formic acid/water (3:6:1, v/v/v), HCl as the catalyst, 90 °C and 180 min residence time, where the yield (and purity) of crude cellulose and lignin products were approximate 53% (85%) and 38% (44%), respectively, on the basis of mass of oven-dried cornstalk, and the obtained crude cellulose products have very low residual lignin contents (<4%). The crude cellulose fractionated from cornstalk was further used, after bleaching, as feedstock for the synthesis of sodium carboxymethyl cellulose (CMC). The best molar ratio of the reaction reagents (NaOH/ClCH2COOH /cellulose) among the test conditions were investigated and determined to be 4.0:2.5:1 and 4.6:2.8:1, or the molar ratio of NaOH/ClCH2COOH being 1.6-1.64. The CMC products obtained at the best reactants molar ratios have relatively high water solubility and reasonably high viscosity and molecular weights. The average degree of substitution (DS) of these two CMC products obtained at the best molar ratios among the test conditions are 0.57 and 0.85, respectively.

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