Relaxation phenomenon and swelling behavior of regenerated cellulose fibers affected by organic solvents

Akari Okugawa; Yoshiaki Yuguchi; Chihiro Yamane

doi:10.1016/j.carbpol.2021.117656

Relaxation phenomenon and swelling behavior of regenerated cellulose fibers affected by organic solvents

Carbohydr Polym. 2021 May 1:259:117656. doi: 10.1016/j.carbpol.2021.117656. Epub 2021 Jan 18.

Authors

Akari Okugawa¹, Yoshiaki Yuguchi², Chihiro Yamane³

Affiliations

¹ Faculty of Home Economics, Kobe Women's University, 2-1 Aoyama Higashisuma, Suma-ku, Kobe, Hyogo 654-8585, Japan. Electronic address: a-okugawa@suma.kobe-wu.ac.jp.
² Faculty of Engineering, Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa, Osaka 572-8530, Japan.
³ Faculty of Home Economics, Kobe Women's University, 2-1 Aoyama Higashisuma, Suma-ku, Kobe, Hyogo 654-8585, Japan.

PMID: 33673982
DOI: 10.1016/j.carbpol.2021.117656

Abstract

Regenerated cellulose fibers are extremely sensitive to water. In particular, their mechanical properties are greatly affected by water. Recently, it was clarified that the glass transition temperatures of regenerated cellulose over 500 K can be shifted to room temperature, and small-angle X-ray scattering (SAXS) showed the maxima and shoulders on the equator line in the wet state. In this study, glass transition caused by organic solvents was observed, although the peak heights of tangent δ (tan δ) were low, which suggested the regions affected by organic solvents were small. SAXS showed the maxima and shoulders, suggesting that organic solvents decreased the density of the amorphous region, i.e., widened space between cellulose molecules, creating sufficient space for the micro-Brownian motion of cellulose main chains. However, alkanes with molecular weight larger than n-nonane did not show tan δ peaks, which suggests that the solvent is hard to enter between microfibrils.

Keywords: Organic solvent; Regenerated cellulose fiber; Relaxation phenomenon; Swelling behavior; Synchrotron X-ray; Tan δ.