Transition from cellulose i family to cellulose ii family

Abstract

To make clear the mechanism of the transition from Cell (cellulose) I to Cell II, the changes of the crystal structure and the chain conformation during the mercerization reaction process are studied under various conditions by means of wide angle X-ray diffractograms and CP/MAS 13C NMR spectra. It was observed that Cell I and Cell II show the different 13C NMR spectra resulting from the different chain conformations. In Na-cells treated with three conditions of fixing the fibers, CP/MAS 13C NMR spectra show different patterns which result from two types of the chain conformations, that is Na-cell of Cell I type and that of Cell II type. By regeneration, the Na-cell of Cell II type conformation transforms to Cell II regardless of the temperature of washing water. On the other hand, the Na-cell of Cell I type conformation mostly transforms to Cell I by washing with water at higher temperature. From these results, it seems reasonable to conclude that the transition from Cell I to Cell II is caused by the change of the chain conformation, as proposed by Hayashi. © 1987 The Society of Polymer Science, Japan.