A kind of polycarboxylate superplasticizer with high water reduction and high slump retention and preparation method thereof

Abstract

The invention discloses a high water reducing and high slump retention type polycarboxylate water reducing agent. A copolymer formed by atom transfer radical polymerization; the ligand is one of trimethylolpropane phosphite, bis(triphenylphosphine) nickel dibromide or trimethylolpropane sulfite Two or three of phosphate ester, bis(triphenylphosphine)nickel dibromide, and bis(diphenylphosphine)methane. The invention adopts ATRP atomic free radical polymerization reaction, so that the relative molecular weight distribution of the polymer is reasonable, and at the same time, various functional group structures such as unsaturated alkyl ester groups, acid anhydride groups and anti-mudging groups are introduced, which greatly improves the reduction of Compared with conventional ligands, the selected ligand can stabilize the catalyst well, promote the reaction to proceed, stabilize the intermediate transition state of the reaction, and reduce the generation of by-products.

Description

technical field [0001] The invention relates to the technical field of concrete admixtures, in particular to a high water-reducing and high-slump-retaining polycarboxylate water reducer and a preparation method thereof. Background technique [0002] With the continuous development of modern concrete technology, the application of polycarboxylate high-performance water reducer in concrete is becoming more and more extensive. Containing silt and tailings sand or machine-made sand will lead to an increase in the amount of water reducing agent or excessive slump loss, which will have a great impact on concrete transportation, working conditions and strength. [0003] Chinese patent CN105968266A discloses a preparation method of a super-dispersed polycarboxylic acid-based high-efficiency water reducer. The product synthesized by this patent has stable performance and low cost, and has excellent slump-preserving effect on mud-containing sandstone materials, but The water reducer ...

AI Technical Summary

Problems solved by technology

[0002] With the continuous development of modern concrete technology, the application of polycarboxylate high-performance water reducer in concrete is becoming more and more extensive. Containing silt and tailings sand or machine-made sand, resulting in an increase in the amount of water reducing agent or excessive slump loss, which has a great impact on concrete transportation, working conditions and strength

[0003] Chinese patent CN105968266A discloses a preparation method of a super-dispersed polycarboxylic acid-based high-efficiency water reducer. The product synthesized by this patent has stable performance and low cost, and has excellent slump-preserving effect on mud-containing sandstone materials, but The water reducer of this patent has general dispersibility, and its synthesis steps are cumbersome

[0004] Chinese patent CN103482897A discloses a block polycarboxylate concrete high-efficiency water reducer and its preparation. The water reducer synthesized by this patent solves the problems of uncontrollable polycarboxylate molecular weight, wide molecular weight distribution, and undesignable molecular structure. The efficiency of the synthesized water reducer described in the patent is not high, the conversion rate of the product is not high, and the product is not adaptable to inferior materials.

[0005] Chinese patent CN107586367A discloses a method for preparing slow-release polycarboxylate water reducers based on atom transfer radical polymerization, using a halogenated compound initiator to perform atom transfer radical polymerization on unsaturated amide small monomers to prepare large monomers Under the action of a catalyst and a ligand, the macromonomer initiator initiates the atom transfer radical polymerization of unsaturated carboxylate, unsaturated carboxylate small monomer and unsaturated polyether macromonomer to obtain Water agent, the method steps are complicated, and the product needs to be purified many times to obtain a stable water reducer

[0006] At present, in the application process of concrete, polycarboxylate water reducer adopts compounding or other methods to improve its water reducing effect and control the slump loss of concrete, which has the problems of high cost and limited use. In addition, based on The polycarboxylate water reducer prepared by atom transfer radical polymerization, due to the relatively complex free radical polymerization reaction, is prone to produce by-products. The addition of ligands can carry out a stable reaction on the one hand, and on the other hand may also cause by-products. As a result, the purification steps are complicated and the product purity is not high, which affects the performance of the water reducer

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