Hydrophobically modified viscosity-reducing polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention discloses a hydrophobically modified viscosity-reducing polycarboxylate superplasticizer and a preparation method thereof. The method includes the steps of: adding methyl allyl polyoxyethylene polyoxypropylene ether, hydrophobically modified allyl polyethylene glycol, acrylic acid and deionized water into a reaction kettle, and performing stirring and dissolving to obtain a solutionA; adding hydrogen peroxide into the solution A, also adding a deionized water mixed solution of acrylic acid and ascorbic acid dropwise, and then carrying out heat preservation reaction to obtain a solution B; adding liquid alkali into the solution B, and adjusting the pH value to 6-8, thus obtaining the hydrophobically modified viscosity-reducing polycarboxylate superplasticizer. The hydrophobically modified viscosity-reducing polycarboxylate superplasticizer prepared according to the invention has good dispersibility, slump retention and reinforcement, also has excellent viscosity-reducingperformance, and can greatly improve the comprehensive performance of high-performance or ultrahigh performance concrete.

Description

technical field [0001] The invention relates to the technical field of polycarboxylate water reducer, in particular to a hydrophobically modified viscosity-reducing polycarboxylate water reducer and a preparation method thereof. Background technique [0002] Polycarboxylate superplasticizer, as the third generation superplasticizer product, has the advantages of low dosage, high water reducing rate, good slump retention, strong designability of molecular structure, simple process, green and environmental protection, and easy industrialization. Indispensable key component in concrete. However, the high-performance or ultra-high-performance concrete with high strength and high durability has high viscosity and low fluidity of the mixture due to the high amount of adhesive material and low water-binder ratio, which makes the mixture difficult to discharge, low pumpability, and slow strength growth. , greatly limiting its promotion and application. If the molecular structure d...

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Problems solved by technology

[0006] The above-mentioned technical schemes have successfully prepared a viscosity-reducing polycarboxylate superplasticizer by introducing hydrophobically modified polyether macromonomers or hydrophobic small monomers, but the synthesis process of the hydrophobically modified polyether macromonomers used is complicated. Or if the hydrophobicity is too strong and the water solubility is low, an emulsifier such as alkylphenol polyoxyethyl ether is needed to assist in dispersion, which is not conducive to the improvement of the conversion rate of the polymerization reaction. It is not conducive to the increase of concrete strength, and the small hydrophobic monomer used not only has the problems of poor water solubility and low conversion rate, but also has the problem of low viscosity reduction effect of polycarboxylate superplasticizer when the dosage is low. It will greatly reduce the adsorption and dispersion of polycarboxylic acid, etc.

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