Method for preparing polycarboxylate water reducing agent

Abstract

The invention discloses a polycarboxylate water reducing agent for a gobi desert environment. The polycarboxylate water reducing agent is mainly prepared by the following steps of: synthesizing poly(ethylene glycol methyl ether) maleic anhydride active macromonomer (PAM) by performing esterification reaction on poly(ethylene glycol methyl ether) (MPEG) and maleic anhydride (MAH) which serve as main raw materials; preparing a terpolymer by copolymerization of the PAM, sodium methallyl sulfonate (MAS) and itaconic acid (ITA) which serve as raw materials by free radicals; and neutralizing the terpolymer with a base solution. The polycarboxylate water reducing agent has excellent performance, such as high water reducing ratio, little cement paste gradual loss, high cost performance and the like, so that the problem that monomer with large activity difference is difficult to control is solved, and the requirement of construction in the gobi desert environment can be met.

Description

technical field [0001] The invention relates to the field of preparation of concrete admixtures, in particular to a preparation method of polycarboxylate water reducer. Background technique [0002] As the third generation of high-efficiency water reducer, polycarboxylate water reducer has become a new research topic in the field of concrete admixtures at home and abroad because of its high water reducing rate, small slump loss, good adaptability to cement, and environmental protection. direction. [0003] Recently, the technology of foreign polycarboxylate superplasticizers has developed relatively rapidly, and the control of production processes is relatively mature. According to reports, Japanese polycarboxylic acid products account for more than 70% of the total number of products, and research centers in North America and Europe have also begun to develop and transfer to this direction, while my country is in the stage of research and development, and the comprehensive...

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Problems solved by technology

[0005] The polycarboxylate superplasticizers currently researched in China are difficult to take into account the advantages of plastic retention and high water reducing rate

In the patent CN1948209B, a method for preparing polycarboxylate water reducer from maleic anhydride is disclosed. Although maleic anhydride is easy to undergo esterification reaction with alcohols in this method, the polymer with other monomers cannot reach normal The effect of water reducer; patent CN1636922 discloses a kind of preparation method of polycarboxylate concrete water reduction, although the price of acrylic acid in the synthesis method is low, but the characteristics of the molecular structure of its monomer itself makes the plastic retention performance of the product always better. No improvement; Patent CN101434465A discloses the design and synthesis of a polycarboxylate water reducer with controllable setting time. According to actual application needs, design and synthesize water reducers with different setting times to control the slump of the water reducer The purpose of maintaining capacity, but the water reducing rate of synthetic water reducing agent is low

These water reducing agents are only suitable for use under general conditions, and cannot meet the construction requirements for harsh natural conditions.

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