Preparation method of air-entraining ester polycarboxylate superplasticizer

Abstract

The invention discloses a preparation method of an air-entraining ester polycarboxylate superplasticizer. The preparation method comprises the following steps: (1) preparing an esterification product; (2) copolymerization reaction; and (3) neutralization reaction. According to the preparation method, the esterification product is prepared by esterification of coco fatty acid diethanolamide and unsaturated acid, the preparation method has the advantages of low cost and simplicity and convenience in operation, and the prepared esterification product participates in the next copolymerization reaction, so that a main chain of the polycarboxylate superplasticizer has hydrophilic groups such as amide and the like; the prepared polycarboxylate superplasticizer has good air entraining and foam stabilizing properties, and the workability and the strength of concrete are improved.

Description

technical field [0001] The invention belongs to the technical field of building admixtures, and in particular relates to a preparation method of an air-entraining ester polycarboxylate water reducer. Background technique [0002] With the construction of the country's large-scale infrastructure, nuclear power, water conservancy, bridges and various large-scale projects, the performance requirements of concrete are constantly improving, especially some major projects have strict requirements on the strength, durability and workability of concrete. High demands were made. [0003] Although the excellent water-reducing performance of polycarboxylate superplasticizers has been widely recognized by the industry, at present, due to the poor air-entraining effect of polycarboxylate superplasticizers, they are often used in concrete because of their high viscosity and low air-entrainment, which often lead to the easy mixing of concrete. The performance is poor, and there is a probl...

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Problems solved by technology

[0003] Although the excellent water-reducing performance of polycarboxylate superplasticizers has been widely recognized by the industry, at present, due to the poor air-entraining effect of polycarboxylate superplasticizers, they are often used in concrete because of their high viscosity and low air-entrainment, which often lead to the easy mixing of concrete. The performance is poor, and there is a problem of difficult pumping

At present, to solve the problem of poor air-entraining agent, compound air-entraining agent is often used to improve air-entraining performance, but the amount of air-entraining agent is small, and it is difficult to control in actual construction. If the amount is too large, the amount of air introduced into the concrete will be too large. If the amount is too small, its effect will be weak, and it will be difficult to improve the poor workability of concrete, which will affect the construction performance, resulting in little increase in the resistance of concrete to climate change and chemical erosion, and will affect the durability of concrete. The improvement is also slight

[0004] Patent CN 106380554 A discloses a method for preparing an ester viscosity-reducing polycarboxylate superplasticizer. The publication date is February 8, 2017. Polyethylene glycol monomethyl ether and methyl methacrylate are used for esterification Prepare the esterification product, carry out polymerization reaction with the esterification product and unsaturated sulfonic acid, cross-linking monomer, cationic monomer under the action of emulsifier and initiator, chain transfer agent, however the water reducer involved in this scheme although It has good dispersibility, viscosity reduction and mud resistance, but it does not have good air-entraining and foam-stabilizing properties

[0005] At present, there are few studies on air-entraining polycarboxylate superplasticizers, so it is important to develop an air-entraining ester polycarboxylate superplasticizer without compounding air-entraining agents, so as to directly improve the air-entraining performance of concrete. the meaning of

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