Preparing method for polycarboxylate-type anti-mud water reducer with modified side chain terminal group

Abstract

The invention discloses a preparing method for polycarboxylate-type anti-mud water reducer with a modified side chain terminal group. The preparing method includes the steps that azido-terminated polycarboxylate-type water reducer is prepared first, and then the azido-terminated polycarboxylate-type water reducer and an alkyne-terminated benzene-pyridine derivative are subjected to a click chemical reaction to prepare the polycarboxylate-type anti-mud water reducer with the side chain terminal group being the alkyne-terminated benzene-pyridine derivative. As the terminal hydroxyl group of the polycarboxylate-type water reducer is modified into a five-membered ring and a benzene/pyridine ring, the physical size of the side chain terminal of the polycarboxylate-type water reducer is greatly increased, and the polycarboxylate-type water reducer is not prone to be inserted into a layered structure of clay to achieve the anti-mud effect without affecting the inherent functions. The technical problems that as a side chain of existing polycarboxylate-type water reducer is prone to be inserted into the layered structure of the clay, the polycarboxylate-type water reducer is lost fast, and then the work performance of concrete is lowered are solved.

Description

technical field [0001] The present invention relates to the technical field of a polycarboxylate water-reducer for cement concrete, in particular to a side-chain end-group modified polycarboxylate mud-resistance water-reducer modified by a click chemical method method of preparation. Background technique [0002] Polycarboxylate superplasticizer is widely used because of its low dosage, high water reducing rate, low concrete shrinkage, and environmental protection. However, in the actual production and application of concrete, it is found that the mud in the aggregate will absorb the polycarboxylate superplasticizer. The traditional polycarboxylate superplasticizer is very sensitive to the mud content in the aggregate. As the mud content increases, the polycarboxylate superplasticizer The dispersibility and slump retention performance of the carboxylic acid superplasticizer are significantly reduced, resulting in a significant decrease in the workability of fresh concrete. ...

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Problems solved by technology

[0003] At present, the main way to deal with concrete mud is to modify the traditional polycarboxylate superplasticizer. The main methods are divided into three types: the first is to esterify first, that is, to modify the polyether unsaturated macromonomer by esterification first. properties, and then copolymerized with other small molecule monomers, this method is prone to side reactions, and the obtained macromolecular polyether double bond retention value is not high, which will affect the subsequent copolymerization reaction, resulting in a decline in product quality and instability; the second The first method is the post-esterification method. Although the disadvantages of the pre-esterification method can be avoided, the polycarboxylate water reducer is first synthesized by free radical polymerization, and then esterified and grafted. Although this method does not affect the subsequent copolymerization reaction, However, the process is very complicated, and the efficiency of re-esterification of macromolecules of water reducing agent is difficult to improve, and side reactions are prone to occur

The third is to add a third monomer, such as styrene, quaternary ammonium salt and other unsaturated small monomers directly into the main chain, which turns the simple direct free radical polymerization of two monomers into three One kind of monomer, or even four or five kinds, increases a lot of uncertainty, seriously affects the water reducing ability of traditional water reducing agents, and the anti-mud effect is not very obvious

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