Preparation method of ultra-low hydration heat polycarboxylate-based water reducing agent

A technology of thermal polycarboxylic acid and water reducing agent, which is applied in the field of preparation of ultra-low hydration heat polycarboxylic acid series water reducing agent, can solve the problems of single performance of the water reducing agent, and achieves good appearance quality and improved compressive strength. , the effect of small color difference

Inactive Publication Date: 2008-10-15
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above prior art shows that there are still large differences in the structural design of polycarboxylate-based water-reducers, and the performance of the water-reducers themselves is single

Method used

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  • Preparation method of ultra-low hydration heat polycarboxylate-based water reducing agent
  • Preparation method of ultra-low hydration heat polycarboxylate-based water reducing agent
  • Preparation method of ultra-low hydration heat polycarboxylate-based water reducing agent

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Add 16.67g of water into the reactor, heat up, and dropwise add 10.3g of methacrylic acid, 8.0g of polyethylene glycol monomethyl ether methacrylate (molecular weight 500) and 20.95g of water at a temperature of 80 to 90°C. Composed solution (weigh methacrylic acid and polyethylene glycol monomethyl ether methacrylate, and then dissolve in water to obtain), the other side drops initiator and modifier solution (0.73g azobisisobutyl Nitrile, 0.05g ferrous sulfate, 0.45g polyhydric alcohol (q=1) and 38.01g water are mixed), control the dropping speed, finish dropping in 6-7h, and keep warm at 90-95°C for 4-5h. Cool to room temperature, adjust pH=7~8 with sodium hydroxide, obtain the ultra-low heat of hydration polycarboxylate water-reducer of the present invention (the carboxyl group grafted on the main chain and the mole of polyoxyethylene group) of the present invention The ratio is about 7:1).

Embodiment 2

[0028] Add 16.67g of water into the reactor, heat up, and dropwise add 10.8g of methacrylic acid, 15.5g of polyethylene glycol monomethyl ether methacrylate (molecular weight 400) and 33.75g of water at a temperature of 80±5°C. formed solution, the other side was added dropwise initiator and modifier solution (1.05g azobisisobutyronitrile, 0.107g ferrous sulfate, 0.85g polyhydric alcohol (q=4) and 57.92g water), and the rate of addition was controlled. After 6-7 hours of dripping, keep warm at 90-95°C for 4-5 hours. Cool to room temperature, adjust pH=7~8 with sodium hydroxide, obtain the ultra-low heat of hydration polycarboxylate water-reducer of the present invention (the carboxyl group grafted on the main chain and the mole of polyoxyethylene group) of the present invention The ratio is about 3:1).

Embodiment 3

[0030] Add 16.67g of water into the reactor, heat up, and dropwise add 8.2g of methacrylic acid, 26.1g of polyethylene glycol monomethyl ether methacrylate (molecular weight 300) and 46.55g of water at a temperature of 80±5°C. formed solution, the other side was added dropwise initiator and modifier solution (1.37g azobisisobutyronitrile, 0.152g ferrous sulfate, 1.35g polyhydric alcohol (q=10) and 77.95g water), control the rate of addition, After 6-7 hours of dripping, keep warm at 90-95°C for 4-5 hours. Cool to room temperature, adjust pH=7~8 with sodium hydroxide, obtain the ultra-low heat of hydration polycarboxylate water-reducer of the present invention (the carboxyl group grafted on the main chain and the mole of polyoxyethylene group) of the present invention The ratio is about 1:1).

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Abstract

The invention relates to a method for preparing an ultra-low hydration-heat polycarboxylate-based water reducing agent. Methacrylic acid and Monomer methylacrylic acid polyethylene glycol single armor ether ester (MAAMPEA) water solution, initiator and modifier solution are simultaneously and slowly added into the solvent water drop by drop within 6 to 7 hours at the temperature of 80 DEG C to 90 DEG C, then the solvent water is subjected to thermal insulation for 4 to 5 hours at 90 DEG C to 95 DEG C and is naturally cooled down to the room temperature, and finally NaOH is used to adjust the pH value to 7 to 8, thereby obtaining the ultra-low hydration-heat polycarboxylate-based water reducing agent. The reaction conditions are easily controlled, no organic solvent is used during the polymerization process, and the process is simple with no industrial pollution. The concrete prepared by adopting the ultra-low hydration-heat polycarboxylate-based water reducing agent has the advantages as follows: when the mixing amount of the water reducing agent with the concentration being 25 wt percent is 1.0% of the concrete weight, the water reducing ratio can reach 30 percent, the 3d compressive strength of the concrete can be improved by more than 60 percent, the 28d compressive strength can be improved by more than 50 percent, and the 90d compressive strength can be improved by 30 percent.

Description

technical field [0001] The invention belongs to a preparation method of an ultra-low heat of hydration polycarboxylate water reducer. Background technique [0002] High-efficiency water reducer is a core technology in high-performance concrete. Since the research and development of high-efficiency water reducer, it has gradually developed into the current high-efficiency water reducer mainly represented by polycarboxylic acid through the stages of lignosulfonate, naphthalene-based and melamine-based high-efficiency water-reducers. Compared with traditional water reducers, polycarboxylate high-efficiency water reducers are mainly composed of carboxyl groups (-COOR) and polyoxyethylene grafted chains (-OC 2 h 4 -) composed of comb-shaped copolymers, these polar groups with strong affinity for water provide dispersibility and dispersion retention for cement particles through adsorption, electrostatic repulsion, wetting and other surface activities, even at low water-binder ra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B24/24C04B24/04C04B103/30
CPCC04B40/0039C04B2103/302
Inventor 马保国张慢马玲谭洪波李亮吕国玉何向全许红生
Owner WUHAN UNIV OF TECH
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