A long-chain branched terminal esterification modified polycarboxylate water reducer and its preparation method

Abstract

The invention provides a long-chain branch end group esterified and modified polycarboxylate water reducer. The polycarboxylate water reducer is prepared through copolymerization of three monomers under the actions of an initiator and a chain transfer agent, wherein the three monomers are respectively 5-15 parts by weight of unsaturated monocarboxylic acid, 5-30 parts by weight of a carboxyl-terminated polyether macromonomer and 55-90 parts by weight of a first polyether macromonomer, the initiator accounts for 0.5%-4% of the total weight of the monomers, and the weight of the chain transfer agent accounts for 0.1%-1% of the total weight of the monomers. The novel polycarboxylate water reducer has good adaptability to mud contained in concrete aggregates, the preparation process is simple, and the polycarboxylate water reducer can be mixed with conventional polycarboxylate water reducers for use in any proportion.

Description

technical field The invention belongs to the technical field of concrete admixtures, and in particular relates to a long-chain branched end group esterified modified polycarboxylate water reducer and a preparation method thereof. Background technique Polycarboxylate superplasticizer is extremely sensitive to the mud content of sand and gravel, and sand and gravel with high mud content are used in concrete, which will greatly increase the amount of polycarboxylate superplasticizer in concrete, and significantly increase the cost of concrete. In addition, increasing the amount of water reducing agent will often cause concrete retardation, thereby prolonging the construction period. At present, there are three main ways to improve the anti-mud effect of polycarboxylate superplasticizers. The first is to compound polycarboxylate superplasticizers with cationic small molecular substances. The second is to use vinyl cationic monomers to block-modify the main chain of the polycar...

AI Technical Summary

Problems solved by technology

Polycarboxylate superplasticizer is extremely sensitive to the mud content of sand and gravel, and sand and gravel with high mud content are used in concrete, which will greatly increase the amount of polycarboxylate superplasticizer in concrete, and significantly increase the cost of concrete

In addition, increasing the amount of water reducing agent will often cause concrete retardation, thereby prolonging the construction period

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