On the orientation of the chains in the mercerized cellulose

Dmitry V Zlenko,Sergey V Usachev,Sergey N Nikolsky,Sergey V Stovbun,Mariya G Mikhaleva,Daria N Vtyurina,Galina G Politenkova,Aleksey A Skoblin

doi:10.1038/s41598-021-88040-x

Dmitry V Zlenko, Sergey V Usachev + Show 6 more

Open Access

https://doi.org/10.1038/s41598-021-88040-x

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Journal: Scientific Reports	Publication Date: Apr 22, 2021
Citations: 8	License type: open-access

Affiliation: Semenov Institute of Chemical Physics

Abstract

The cold alkaline treatment or mercerization of cellulose is widely used in industry to enrich the cellulose raw with high-molecular-weight alpha-cellulose. Washing out of hemicelluloses by alkalies is accompanied by the rearrangement of the cellulose chains’ packing, well known as a transition between cellulose I and cellulose II. Cellulose II can also be produced by the precipitation of the cellulose solutions (regeneration). The currently accepted theory implies that in cellulose II, both mercerized and regenerated, the macromolecules are arranged antiparallelly. However, forming such a structure in the course of the mercerization seems to be significantly hindered, while it seems to be quite possible in the regeneration process. In this work, we discuss the sticking points in the theory on the antiparallel structure of mercerized cellulose from a theoretical point of view summarizing all of the available experimental data in the field.

Highlights

The cold alkaline treatment or mercerization of cellulose is widely used in industry to enrich the cellulose raw with high-molecular-weight α-cellulose
A relatively low degree of polymerization (DP) microcrystalline cellulose (MCC) almost completely dissolves in a lkalies[21,26], and such solutions remain stable at room temperature for weeks[26]
The degree of polymerization (DP) in the studied samples did not change significantly during the mercerization process. It amounted to 1250–1500 and 1400–1650 for hardwood and linter cellulose, correspondingly, while DP of the flax cellulose was substantially higher than 10,00044

Summary

Introduction

The cold alkaline treatment or mercerization of cellulose is widely used in industry to enrich the cellulose raw with high-molecular-weight α-cellulose. In the native cellulose I, the chains are oriented in parallel, and their directions coincide, which was confirmed by the numerous experimental works[4,17,18,19] and usually considered to be well-proven. It is well-known that cellulose swells and partially dissolves in aqueous solutions of sodium hydroxide at low temperatures[20,21,22,23,24]. This observation allows explaining the antiparallel packing by the mutual interpenetrating of the Scientific Reports | (2021) 11:8765

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