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Determination method of pulp polymerization degree distribution

A method for measuring the degree of polymerization, which is applied in the fields of chemical industry and textiles, can solve problems such as the inability to accurately obtain the molecular weight of pulp cellulose, the size of the molecular chain, the inability to understand the distribution of the degree of polymerization, and the uneven degree of polymerization of pulp. The detection method is simple and fast, the strength is guaranteed, and the detection cost is low.

Inactive Publication Date: 2012-07-11
YIBIN GRACE GROUP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The medicines and instruments required by the above two methods are easy to buy, and the operation is relatively simple, but because the degree of polymerization of the pulp is not uniform, only the average degree of polymerization can be measured and the distribution of the degree of polymerization cannot be understood.
[0006] This will cause discrepancies between the measured pulp polymerization degree and the actual pulp polymerization degree, and the molecular weight and molecular chain length of the pulp cellulose cannot be accurately obtained, which directly affects the yarn quality in the subsequent spinning process. Strength, especially breaking strength in wet state

Method used

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  • Determination method of pulp polymerization degree distribution
  • Determination method of pulp polymerization degree distribution
  • Determination method of pulp polymerization degree distribution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] A. Weigh 2 grams of wood pulp samples, disperse the plate-like wood pulp into single fibers with a fiber dissociation device, and bake in an oven at 52°C for 4 hours until the water content is <5%;

[0028] B. Put 250 milliliters of dichloromethane and 115 grams of fuming nitric acid with a concentration of 99% into a 250 milliliter conical flask with a ground stopper, and place it in an ice-salt bath to cool to -5°C, and then slowly add 76 grams of phosphorus pentoxide, during which the temperature is kept below 0°C. When the temperature rises to 0°C, the addition of phosphorus pentoxide is stopped, and it is cooled to -5°C in ice salt water before continuing to add phosphorus pentoxide. After the mixed acid is prepared, the Erlenmeyer flask is taken out from the ice-salt water bath and put into the dried wood pulp sample, the bottle stopper is plugged, and the nitration reaction is carried out by rotating and shaking, the temperature is controlled at 25°C, and the reac...

Embodiment 2

[0034] A. Weigh 2 grams of cotton pulp sample, disperse the plate-shaped cotton pulp into single fibers with a fiber dissociation device, and dry in an oven at 50°C for 4.5 hours until the water content is <5%;

[0035] B. Put 250 milliliters of dichloromethane and 115 grams of fuming nitric acid with a concentration of 99% into a 250 milliliter conical flask with a ground stopper, and place it in an ice-salt bath to cool to -5°C, and then slowly add 76 grams of phosphorus pentoxide, during which the temperature is kept below 0°C. When the temperature rises to 0°C, the addition of phosphorus pentoxide is stopped, and it is cooled to -5°C in ice salt water before continuing to add phosphorus pentoxide. After the mixed acid is prepared, take the Erlenmeyer flask out of the ice-salt water bath and put it into the dried cotton pulp sample, plug the bottle stopper, rotate and shake to carry out the nitration reaction, the temperature is controlled at 18°C, and the reaction is 0.5 ho...

Embodiment 3

[0041] A, take 2 grams of bamboo pulp samples, disperse the plate-shaped bamboo pulp into single fibers with a fiber dissociator, and dry in a 52°C oven for 4 hours until the water content<5%;

[0042] B. Put 250 milliliters of dichloromethane and 115 grams of fuming nitric acid with a concentration of 99% into a 250 milliliter conical flask with a ground stopper, and place it in an ice-salt bath to cool to -5°C, and then slowly add 76 grams of phosphorus pentoxide, during which the temperature is kept below 0°C. When the temperature rises to 0°C, the addition of phosphorus pentoxide is stopped, and it is cooled to -5°C in ice salt water before continuing to add phosphorus pentoxide. After the mixed acid is prepared, the Erlenmeyer flask is taken out from the ice-salt water bath and put into the dried bamboo pulp sample, the bottle stopper is plugged, and the nitrification reaction is carried out by rotating and shaking. The temperature is controlled at 10°C and the reaction is...

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Abstract

The invention discloses a determination method of pulp polymerization degree distribution, comprising the following process steps: Weighing a pulp sample, dispersing the pulp into single fibers, drying the single fibers until the moisture content of the single fibers is less than 5%, placing methylene chloride and fuming nitric acid into a flask, cooling in an ice salt bath, adding phosphorus pentoxide to obtain mixed acid, taking out the flask, and adding the pulp sample with water content being less than 5 % for nitrification; filtering by a sand core funnel, washing the nitrocellulose in the funnel with methylene chloride, and then washing with methanol, and finally washing with distilled water fully until the pH is equal to 7, placing in boiling water for boiling, filtering and blotting up, washing with cold distilled water again, and then drying in a drying oven until the moisture content is less than or equal to 10%; dissolving the sample with tetrahydrofuran, preparing solution with cellulose content of 0.1%, and determining the polymerization degree with GPC (gel permeation chromatography). In the invention, precise molecular weight and molecular chain length of pulp cellulose can be obtained, and thread line strength can be ensured.

Description

technical field [0001] The invention relates to a method for measuring the degree of polymerization of pulp, in particular to a method for measuring the distribution of degree of polymerization of pulp by using gel permeation chromatography, and belongs to the technical fields of chemical industry and textile. Background technique [0002] The degree of polymerization (DP, Xn) (Decree of Polymerization) is an index to measure the molecular size of a polymer. Based on the number of repeating units, that is, the average value of the number of repeating units contained in the polymer macromolecular chain, represented by n; based on the number of structural units, that is, the average value of the number of structural units contained in the polymer macromolecular chain, Represented by X. [0003] Since the degree of polymerization represents the molecular weight of pulp cellulose and the length of the molecular chain, which directly affects the strength of the filaments in th...

Claims

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Application Information

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IPC IPC(8): G01N30/00C08B5/02
Inventor 徐发祥黄俊马志强
Owner YIBIN GRACE GROUP CO LTD
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