Cellulose polymerization degree determination method

Abstract

The invention relates to a cellulose polymerization degree determination method. The cellulose polymerization degree determination method comprises the following steps of 1, stirring dimethyl sulfoxide and 1-ethyl-3-methylimidazolium acetate to obtain a uniform mixed solvent, 2, putting the mixed solvent into an Ubbelohde viscometer and measuring flowing time t0 of the mixed solvent in the Ubbelohde viscometer, 3, drying cellulose to be measured until weight is constant and adding the cellulose into the mixed solvent to obtain a cellulose solution having a concentration c, 4, putting the cellulose solution obtained by the step 3 into the Ubbelohde viscometer, putting the Ubbelohde viscometer with the cellulose solution into a thermostatic water bath having a temperature of 25 DEG C, carrying out thermostatic treatment for 20-30min, and determining flowing time t0 of the cellulose solution in the Ubbelohde viscometer, 5, calculating h<sp> / c according to the formula (I) and calculating an [Eta] value according to the formula (II), and 6, calculating a DP value according to the formula (III). The cellulose polymerization degree determination method has simple and easy processes, is free of expensive equipment, has a low cost, is convenient for use, has short determination time and produces accurate test data.

Description

technical field [0001] The invention relates to the technical field of measuring the degree of polymerization, in particular to a method for measuring the degree of polymerization of cellulose. Background technique [0002] The cellulose molecules of cellulose materials are extremely long chain molecules composed of D-glucopyranosyl (C 6 h 10 o 5 , anhydrous glucose) composition. The number of glucose groups in a cellulose molecule is called the degree of polymerization (DP) of cellulose. The degree of polymerization of cellulose represents the length of cellulose molecular chains and the strength of cellulose. The degree of polymerization of cellulose can objectively and quantitatively reflect the degree of damage to fibers in the actual processing of spinning, weaving and dyeing, and is also an important indicator to measure fiber quality. [0003] Methods for determining the degree of cellulose polymerization include end-group chemical titration, boiling point rise m...

AI Technical Summary

Problems solved by technology

Cuproammonia solution and copper ethylenediamine solution all easily lead to severe oxidative degradation of cellulose, and are extremely unstable and difficult to store; moreover, the reagents used for preparing these two solutions are many, the preparation process is complicated, and the preparation period is long; in addition, due to In the process of dissolving cellulose, copper particles or copper sheets need to be added, and the cellulose will be sandwiched between copper particles or copper sheets, resulting in insufficient dissolution

In contrast, cadmium ethylenediamine solutions are more stable, but also cause mild oxidative degradation of cellulose

Obviously, using these solvents to dissolve cellulose to measure the degree of cellulose polymerization, in addition to having appealing defects, will also cause relatively large errors, which will ultimately affect the accuracy of the measurement data

Despite their shortcomings, these solvents are still used to date because there are no better-dissolving, more stable alternatives