Method for preparing polycarboxylic acid slump-retaining agent by atom transfer radical polymerization

Abstract

The invention relates to a method used for preparing a polycarboxylic acid slump retaining agent via atom transfer radical polymerization. According to the method, a halogenated compound initiator isadopted for atom transfer radical polymerization of an unsaturated amide small monomer so as to prepare a large monomer initiator; at the same time, a polyethylene glycol compound and an unsaturated carboxylic acid are adopted to prepare an esterfied large monomer; under the action of a catalyst and a ligand, atom transfer radical polymerization of the esterfied large monomer, the unsaturated amide small monomer, and an unsaturated carboxylate is induced by the large monomer initiator so as to obtain a finished product. The process of the method is simple, and is easy to control; cost is low;the method is friendly to the environment; no pollution is caused; the molecular weight of the polycarboxylic acid slump retaining agent is controllable; molecular weight distribution is narrow; the molecular structure is devisable; and application prospect is promising.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylic acid slump-retaining agent for cement concrete, in particular to a method of preparing a macromonomer initiator by using unsaturated amide small monomers to initiate esterification of macromonomers and unsaturated carboxylic acids A specific preparation method for preparing a polycarboxylic acid slump retaining agent by atom transfer radical polymerization of small monomers. Background technique [0002] Polycarboxylate high-performance water reducer is the third generation of high-performance water reducer developed after the ordinary water reducer represented by lignin and the high-efficiency water reducer represented by naphthalene. It is currently the most advanced water reducer in the world. , a superplasticizer with the highest technological content, the best application prospects, and the best comprehensive performance. It has the advantages of non-toxicity, environmental protectio...

AI Technical Summary

Problems solved by technology

Most of the synthesis methods are still traditional free radical polymerization, which will cause problems such as uncontrollable molecular weight of polycarboxylic acid, wide molecular weight distribution, and lower expectations of molecular structure design, making it difficult to achieve ideal structure and performance results.

Although some patents prepare polycarboxylate polymers by atom transfer radical polymerization, they are not suitable for the field of polycarboxylate slump-retaining agents for concrete, nor do they use polyethylene glycol compounds as side chain structures of synthetic products. As a result, the steric hindrance effect cannot be reflected in the concrete system

Even though there are a few patents that use atom transfer radical polymerization to prepare polycarboxylate superplasticizers, the entire preparation process is complex, cumbersome to operate, high in preparation costs, and the finished product is not effective due to structural defects, which limits its production and application.

Therefore, the use of atom transfer radical polymerization to prepare ideal polycarboxylic acid polymers with controllable molecular weight, narrow molecular weight distribution and regular molecular structure used in the field of polycarboxylate slump retention agents is conducive to achieving better fluidity and slump retention. and adaptability, while ensuring its easy operation, low preparation cost, and easy industrial production. There have been no reports on this aspect at home and abroad.

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