Method for preparing slow-release polycarboxylate water reducer based on atom transfer radical polymerization

Abstract

The invention relates to a slow-release polycarboxylate superplasticizer preparation method based on atom transfer radical polymerization. Firstly, a macromonomer initiator is prepared through atom transfer radical polymerization of unsaturated amide micromonomers with a halogenated compound initiator, unsaturated carboxylic ester, unsaturated carboxylate micromonomers and unsaturated polyether macromonomers are initiated by a macromonomer initiator under the action of a catalyst and ligand to be subjected to atom transfer radical polymerization, and thus, the slow-release polycarboxylate superplasticizer is prepared. The method is reasonable in process, simple to operate, low in preparation cost, environmentally friendly and pollution-free, and the slow-release polycarboxylate superplasticizer prepared with the method has a slow release effect on fluidity of concrete and can effectively prevent loss of concrete slump due to long-term transportation. The polycarboxylate superplasticizer prepared with the method also has the advantages of controllable molecular weight, narrow molecular weight distribution and designable molecular structure and has greater application potentials.

Description

technical field [0001] The invention relates to the technical field of a slow-release polycarboxylate water reducer for cement concrete, in particular to a macromonomer initiator prepared by using unsaturated amide small monomers to initiate unsaturated polyether macromonomers and A specific preparation method for preparing a slow-release polycarboxylate water reducer by atom transfer radical polymerization of small unsaturated carboxylic acid monomers. Background technique [0002] In recent years, with the rapid development of my country's construction industry, the application problems of concrete engineering have become more and more obvious, such as the large difference of concrete raw materials affected by regions, the large slump loss during the transportation of coagulation, and the rapid evaporation of concrete moisture at high temperatures. Water reducers put forward more and higher requirements. At present, the water reducer with the best application prospect and ...

AI Technical Summary

Problems solved by technology

First of all, most of the synthesis methods are traditional free radical polymerization, which will cause problems such as uncontrollable molecular weight of polycarboxylic acid, wide molecular weight distribution, and low degree of realization of molecular structure design. The inventors often achieve this by changing the reaction raw materials and their proportions. Ideal performance, but few people try new polymerization methods; although as mentioned above, there have been some reports on atom transfer radical polymerization, but its polymerization products are not suitable for the field of polycarboxylate superplasticizers, the product molecules The structure does not contain anchoring groups such as carboxyl groups, so it is difficult to achieve the effect similar to the adsorption of superplasticizers on the surface of cement particles, and cannot provide sufficient electrostatic repulsion; some patents use atom transfer radical polymerization to prepare polycarboxylate superplasticizers, but their main Chain polymerization still belongs to traditional free radical polymerization, the molecular weight is not easy to control, and its block structure will also lead to poor application performance of polycarboxylate superplasticizer

Therefore, the use of atom transfer radical polymerization to prepare ideal polycarboxylate polymers with controllable molecular weight, narrow molecular weight distribution, and regular molecular structure can be used in the field of slow-release polycarboxylate superplasticizers, which is conducive to achieving better fluidity and fluidity to maintain performance, but also to ensure that its process is simple, the preparation cost is low, and it is easy to industrialized production. There is no report on this aspect at home and abroad.

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