Myung-Joon Jeong

Finally Dissolved! Activation Procedures to Dissolve Cellulose in DMAc/LiCl Prior to Size Exclusion Chromatography Analysis - A Review

This review describes several methods for activating cellulose so that it dissolves in N,N- dimethylacetamide/lithium chloride and can then be analyzed by size exclusion chromatography (SEC) and light scatter- ing for the determination of molar mass and molar mass distribution (MMD). This contribution lists the effects of these methods and approaches on the molar mass distribution of cellulose. Cellulose I and cellulose II behave differently and are considered separately. The activation procedures are grouped according to mechanical, chemical, and biological mechanisms. The mechanical processes include milling, freeze drying, steam explosion, and ultrasonic treatment, while chemical mechanisms are heating, irradiation, alkaline pretreatment, and derivatization strategies are discussed. Treat- ments with ethylene diamine and ionic liquids are also summarized from chemical aspects. Enzymes represent the bio- logical strategy for treating solubility problems involving cellulose. These activation mechanisms are reviewed with re- gard to their efficiency, effect on MMD, and possible side reactions.

Deterioration of ancient Korean paper (Hanji), treated with beeswax: A mechanistic study

In the early 15th century, beeswax coating was applied to some of the cellulosic documents in a futile attempt to better conserve the paper. However, this treatment caused much more severe degradation compared to untreated Hanji. In the current study, the degradation pathway of this beeswax-treated Hanji has been clarified for the first time. The degradation of cellulose was investigated by labeling of oxidized groups combined with gel permeation chromatography, providing profiles of carbonyl and carboxyl groups relative to the molar mass distribution. The beeswax caused purely hydrolytic damage, leading to a decrease in molar mass to about one fifth of the original value. Oxidative degradation, by contrast, did not occur to any significant extent. Hydrolysis was not caused by acids but by microorganism feeding on the beeswax and excreting cellulolytic enzymes, which cause similar cellulose damage patterns. The hydrolytic enzymes were identified by typical metabolites present in the Hanji.