Preparation method of ester type viscosity reduction type polycarboxylate superplasticizer

Abstract

The invention discloses a preparation method of an ester type viscosity reduction type polycarboxylate superplasticizer. The method comprises the following steps: (1) preparing an esterified monomer; (2) conducting the copolymerization reaction; (3) conducting the neutralization reaction. According to the technical scheme of the preparation method, methyl methacrylate and dimethylaminoethanol, remaining after the preparation of the esterified monomer, are subjected to ester exchange in the same condition of preparing the esterified monomer so as to obtain dimethylaminoethyl methacrylate as a functional monomer. Therefore, the preparation method is cost-saving and simple in operation. In addition, the functional monomer is directly introduced into the copolymerization reaction to react with other cationic monomers. During the polymerization process, anions, cations and tertiary amine groups are attached to polycarboxylic acid molecular chains, so that the surface adsorbability of cement particles can be improved. The electrostatic repulsion effect between cement particles is improved. Not only the ester type viscosity reduction type polycarboxylate superplasticizer is good in anti-sludge effect for sand and gravel materials high in cement content, but also the ester type viscosity reduction type polycarboxylate superplasticizer is good in dispersibility and viscosity-reducing effect.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a preparation method of an ester viscosity-reducing polycarboxylate water reducer. Background technique [0002] With the vigorous development of my country's construction industry, high-rise and super-high-rise concrete structures and important buildings with special functional requirements continue to appear, such as skyscrapers, super-long-span bridges and giant water conservancy projects, etc., requiring concrete to have higher strength , better durability, and better stability. These demands have led to the gradual development of concrete from ordinary to high-performance and even ultra-high-performance. At present, the strength of concrete is mainly improved by reducing the water-cement ratio and increasing the amount of cementitious materials, but these methods will increase the viscosity of concrete and reduce the fluidity, which largely limits the p...

AI Technical Summary

Problems solved by technology

The added organic admixture is mainly air-entraining agent. The incorporation of air-entraining agent will form a large number of tiny closed spherical bubbles in the concrete mixture. These micro-bubbles are like balls, reducing the frictional resistance between aggregate particles, thereby reducing the viscosity. , but the viscosity-reducing effect of the air-entraining agent is limited, and the air bubbles introduced will have an adverse effect on the strength of high-strength concrete

However, by adding a large amount of fly ash to improve the performance of concrete, the effect of reducing viscosity for high-rise, high-strength or ultra-high-strength concrete is very limited.

At present, the research on the viscosity-reducing polycarboxylate superplasticizer is still relatively lacking, and there are few good products on the market.

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