A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization

Abstract

The effects of alkali treatment on the structural characteristics of cotton linters and sisal cellulose samples have been studied. Mercerization results in a decrease in the indices of crystallinity and the degrees of polymerization, and an increase in the α-cellulose contents of the samples. The relevance of the structural properties of cellulose to its dissolution is probed by studying the kinetics of cellulose decrystallization, prior to its solubilization in LiCl/N,N-dimethylacetamide (DMAc). Our data show that the decrystallization rate constants and activation parameters are only slightly dependent on the physico-chemical properties of the starting celluloses. This multistep reaction is accompanied by a small enthalpy and large, negative, entropy of activation. These results are analyzed in terms of the interactions within the biopolymer chains during decrystallization, as well as those between the two ions of the electrolyte and both DMAc and cellulose.

Bio-based Films from Linter Cellulose and Its Acetates: Formation and Properties

“…It is known that celluloses obtained from different sources have distinct physico-chemical characteristics. Focusing on the expansion of applications of cellulose, it is important to evaluate how the characteristics of the starting biopolymer influence the pathway of a certain process [ 25 , 26 , 27 ], as well as the properties of the respective final product. The interest in exploring the behavior of different celluloses under the same process motivated the study on the heterogeneous acetylation of microcrystalline and sisal celluloses [ 28 ], where very different results were found when comparing the two celluloses.…”

“…Whereas sisal cellulose can be directly dissolved in LiCl/DMAc, linter cellulose, which possesses longer organized domains and a smaller pore volume than sisal, can only be completely dissolved after some pre-treatment, in particular, mercerization. This treatment has resulted in reduction of both Ic and the crystallite size, as well as a higher homogeneous pore size distribution [ 25 , 27 ].…”

“…The preceding discussion shows the importance of understanding the dependence of a certain aspect of cellulose chemistry, e.g., the efficiency during cellulose derivatization, or the properties of films obtained therefrom on the properties of the starting materials [ 25 , 26 , 27 , 28 , 29 , 30 ]. The present investigation is related to this theme, namely, the performance of celluloses with different characteristics in the synthesis of cellulose acetates for the preparation of films; LiCl/DMAc has been employed as the solvent system for both processes.…”

“…Previous studies have shown the advantages of using a homogeneous medium for the esterification of different starting celluloses [ 26 , 27 ]. Although ionic liquids are considered attractive solvents for the derivatization of cellulose in a homogeneous medium [ 31 , 32 , 33 ], LiCl/DMAc has remained a popular choice, inter alia , because of the negligible degradation of the biopolymer during its derivatization, and the efficient recovery of pure solvent by distillation [ 17 , 26 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

Novel, Environment-Friendly Cellulose-Based Derivatives for Tetraconazole Removal from Aqueous Solution

“…It has been industrial feedstock for a large number of derivatives with an unlimited number of commercial applications. Surface-modified cellulose can also be of great interest due to a wide range of applications [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. This work aims to purify water from tetraconazole using a novel synthesized cellulosic polymer modified with furan-2-carbonyl chloride (Cell-F) and crosslinked with pyridine-2,6-dicarbonyl dichloride (Cell-P).…”