A modified chitosan high-efficiency retarding water reducer and its preparation method and use method

A technology of retarding water-reducing agent and chitosan, which is applied in the field of modified chitosan high-efficiency retarding water-reducing agent and its preparation field, can solve the problem that the water-reducing rate of polycarboxylate-based water-reducing agent decreases the fluidity of concrete, and Sensitive to mud volume, poor adaptability and other problems, to achieve the effect of improving easy bleeding, high water reduction efficiency and long retardation time

Active Publication Date: 2017-03-29
江西富创新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the problem encountered in the application of the third-generation water reducing agent is that its adaptability is poor, and it is sensitive to the variety of cement and the mud content in sand and gravel. It has good adaptability when used in some brands of cement, but in For other brands of cement, the effect may be very poor. At the same time, when the mud content in the sand is greater than 5%, the water-reducing rate of the polycarboxylate-based water-reducing agent and the fluidity of the concrete will drop significantly, making it almost unusable. , the existence of these problems has hindered the popularization and application of polycarboxylate superplasticizers in central my country, especially in Northwest China.

Method used

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preparation example Construction

[0020] A kind of preparation method of modified chitosan high-efficiency retarding superplasticizer of the present invention comprises the following steps:

[0021] Heat 15-20 parts of chitosan and 8-12 parts of itaconic anhydride in a dry, anhydrous reactor to 70-80°C and stir for 30-50 minutes, then heat up to 90-95°C to keep warm React for 2 to 3 hours, after cooling down to 40 to 50°C, slowly add 40 to 50 parts of deionized water under stirring, neutralize with 40% sodium hydroxide solution to a pH value of 6.5 to 7.5, and obtain a product solution Keep the temperature at 45-50°C, add 8-12 parts of mixed monomers, 2-4 parts of initiator solution I and 1.5-3.5 parts of initiator solution II dropwise under stirring, and the dropping time is 1-1.5 hours. After the feeding is completed, continue the heat preservation reaction for 4 to 5 hours, then cool down to 25 to 30°C, neutralize with 40% sodium hydroxide solution to a pH value of 6.5 to 7.5, then add 3 to 5 parts of retar...

Embodiment 1

[0027] A preparation method of a modified chitosan high-efficiency retarding water reducer, comprising the following steps: heating 15 parts of chitosan and 12 parts of itaconic anhydride in a dry, anhydrous reactor to 80° C. and stirring Mix for 30 minutes, then raise the temperature to 90°C and continue the heat preservation reaction for 2 hours, then slowly add 40 parts of deionized water under stirring after cooling down to 40°C, neutralize with a mass fraction of 40% sodium hydroxide solution until the pH value is 6.5, The resulting product solution was kept at a temperature of 45°C, and 8 parts of mixed monomers, 2 parts of initiator solution I (obtained by dissolving ammonium persulfate in water, the mass ratio of ammonium persulfate to water was 1:10) and 3.5 parts of initiator solution II (obtained by dissolving sodium sulfite in water, the mass ratio of sodium sulfite to water is 1:10), the dropwise addition time is 1 hour, after the addition is completed, continue th...

Embodiment 2

[0029] A preparation method of a modified chitosan high-efficiency retarding water reducer, comprising the following steps: heating 18 parts of chitosan and 8 parts of itaconic anhydride in a dry, anhydrous reactor to 70° C. and stirring Mix for 50 minutes, then raise the temperature to 95°C and continue the heat preservation reaction for 3 hours, then slowly add 50 parts of deionized water under stirring after cooling down to 40°C, neutralize with a mass fraction of 40% sodium hydroxide solution until the pH value is 7.5, The resulting product solution was maintained at a temperature of 50°C, and 10 parts of mixed monomers, 2 parts of initiator solution I (obtained by dissolving potassium persulfate in water, the mass ratio of potassium persulfate to water was 1:10) and 2.5 parts of initiator solution II (obtained by dissolving sodium thiosulfate in water, the mass ratio of sodium thiosulfate to water is 1:10), the dropwise addition time is 1 hour, after the addition is comple...

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PUM

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Abstract

The invention discloses a modified chitosan efficient retarding and water-reducing agent and a preparation method and a using method thereof. Chitosan and itaconic anhydride react to prepare double-bond modified chitosan; the modified chitosan, acrylic monomer and sodium allysulfonate are subjected to copolymerization reaction; the product of polymerization reaction is compounded with a retarder to obtain the modified chitosan efficient retarding and water-reducing agent. The modified chitosan efficient retarding and water-reducing agent prepared by the preparation method provided by the invention has the characteristics of high water-reducing efficiency, high adaptability, long retarding time, capability of being used together with a polycarboxylate-type water-reducing agent, and the like.

Description

[0001] 【Technical field】 [0002] The invention relates to the field of water reducing agents for concrete, in particular to a modified chitosan high-efficiency retarding water reducing agent and its preparation method and use method. [0003] 【Background technique】 [0004] Water reducer is an important admixture that must be used in the production and construction of modern concrete. The development of water reducers has experienced the first generation of lignosulfonate water reducers, the second generation of naphthalene sulfonate and sulfamate water reducers, and the third generation of polycarboxylate water reducers. At present, the second-generation water-reducer is the most widely used in China, and the third-generation polycarboxylate-based water-reducer is still being promoted, and its usage is increasing year by year. When the second-generation naphthalene-based water reducer is used, its solid content is about 1% of the cement weight, the water reducing rate can re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F251/00C08F220/06C08F228/02C08B37/08C04B24/16C04B24/06C04B24/00C04B103/30C04B103/22
Inventor 吕生华贾春茂贺亚亚赵浩然周庆芳吕庆强
Owner 江西富创新材料有限公司
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