Preparation method for modified cyclodextrin water reducer

A technology of cyclodextrin and water reducer, which is applied in the field of preparation of modified cyclodextrin water reducer, which can solve the difficulty of engineering construction, affect the popularization and application of polycarboxylate water reducer, and the change of slump retention fluidity It can achieve the effect of being convenient for industrial production, strong adaptability and good compatibility of cement

Inactive Publication Date: 2012-06-20
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the problem of the polycarboxylate water reducer used in the market is that it is adaptable to cement, which shows that the slump fluidity changes greatly, which increases the difficulty of engineering construction and affects the polycarboxylate water reducing agent. Promotion and application of agents

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] Example 1: Put 5 parts of β-cyclodextrin and 4 parts of sodium hydroxide into a three-necked flask according to the number of parts by mass, then add 20 parts of distilled water into the flask and stir to fully dissolve the mixture to obtain 2 parts of chloroacetic acid Dissolve in 12 parts of distilled water to obtain chloroacetic acid solution. At 30°C, drop the chloroacetic acid solution into a three-necked flask, react for 10 hours, and adjust the pH value to 7.0 to obtain the modified cyclodextrin water reducer.

Embodiment 2

[0008] Example 2: Put 5.5 parts of β-cyclodextrin and 4.5 parts of sodium hydroxide into a three-necked flask according to the number of parts by mass, then add 21 parts of distilled water into the flask and stir to fully dissolve the mixture to obtain a mixture, and take 2.5 parts of chloroacetic acid Dissolve in 13 parts of distilled water to obtain chloroacetic acid solution. At 35°C, drop the chloroacetic acid solution into a three-necked flask, react for 9 hours, and adjust the pH to 7.0 to obtain the modified cyclodextrin water reducer.

Embodiment 3

[0009] Example 3: Put 6 parts of β-cyclodextrin and 5 parts of sodium hydroxide into a three-necked flask according to the number of parts by mass, then add 22 parts of distilled water into the flask and stir to fully dissolve the mixture to obtain 3 parts of chloroacetic acid Dissolve in 14 parts of distilled water to obtain chloroacetic acid solution, drop the chloroacetic acid solution into a three-necked flask at 40°C, react for 8 hours, and adjust the pH value to 7.0 to obtain the modified cyclodextrin water reducer.

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PUM

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Abstract

The invention relates to a preparation method for modified cyclodextrin water reducer. Beta-CD (cyclodextrin) originated from natural starch is utilized as raw materials, carboxylic groups are introduced onto beta-CD molecules modified by chloroacetic acid, and the beta-CD has fine dispersity, fluidity and slow setting by the aid of a cavity structure of the beta-CD and hydroxy and carboxylic radicals on the surface of the beta-CD, so that the beta-CD can be independently utilized and also utilized with polycarboxylate water reducer. The beta-CD independently utilized as the water reducer is stable in performance, high in adaptability to cement and good in compatibility with other additives, the cement paste fluidity can reach more than 240mm [W / C (water / cement)=0.35], the concrete water reducing rate can be up to 18-25%, and the slump retention time ranges from 5 hours to 7 hours. When the beta-CD is utilized with the polycarboxylate water reducer, the cement paste fluidity of the polycarboxylate water reducer can be increased by about 30mm, the slow setting and slump retention time can be prolonged by 3-5 hours, overflow, separation and the like of the polycarboxylate water reducer can be effectively prevented, and adaptability of the polycarboxylate water reducer to aggregate containing mud is enhanced.

Description

technical field [0001] The invention belongs to the technical field of concrete water reducers, and relates to a preparation method of a modified cyclodextrin water reducer used in concrete construction. Background technique [0002] The wide application of concrete water reducing agent is conducive to saving resources and energy and is conducive to environmental protection, mainly in improving the workability, fluidity, flow retention performance, strength and other physical and mechanical properties of fresh concrete. Many traditional water-reducing agents are mainly formaldehyde condensates (such as naphthalene sulfonate formaldehyde condensate, sulfonated melamine formaldehyde condensate and sulfamate condensate), although they can improve the fluidity and retardation of concrete to a certain extent. However, free formaldehyde and naphthalene will also be released into the environment, affecting the environment and the health of related personnel. The emergence of polyc...

Claims

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Application Information

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IPC IPC(8): C04B24/38C04B103/30
Inventor 吕生华高瑞军
Owner SHAANXI UNIV OF SCI & TECH
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