Preparation method and application of viscosity-reducing polycarboxylate water reducer

Abstract

The invention provides a preparation method of a viscosity-reducing polycarboxylate superplasticizer and an application thereof. The viscosity-reducing polycarboxylate superplasticizer can remarkably reduce the viscosity of concrete on the premise of guaranteeing high water reduction and high slump loss resistance; and the preparation method has the advantages of simple technology, low cost, little pollution and the like. In the preparation method, a specific unsaturated acid monomer, a specific unsaturated polyether macromonomer and N-(4-vinyl benzyl)-N, N-dialkylamine in a molar ratio of (2.5-6.5):1:(0.05-0.2) are subjected to free radical copolymerization reaction to obtain the viscosity-reducing polycarboxylate superplasticizer.

Description

Technical field [0001] The invention relates to a preparation method and application of a viscosity-reducing polycarboxylic acid water reducer, and belongs to the technical field of concrete admixtures. Background technique [0002] At present, concrete is still the most important and largest material for construction projects. With the rapid development of my country's infrastructure construction, construction projects are developing toward large-scale, high-rise, and complex development, and the requirements for various properties of the required concrete materials are getting higher and higher. Practice has shown that adding chemical admixtures to concrete can greatly improve its working performance. In fact, admixtures have become the fifth important component of modern concrete in addition to cement, sand, stone, and water. Water reducer (also called "cement dispersant") is currently the most widely researched and used concrete admixture. Under the condition that the workab...

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Problems solved by technology

At present, there are many types of polycarboxylate superplasticizer products that introduce the third monomer in the market, but they are mainly slump-preserving products. The urgently needed viscosity-reducing polycarboxylate superplasticizer products are rare, and only a few patents have been reported. Such products, for example, Chinese patent document CN 104262550A discloses a preparation method of a viscosity-reducing polycarboxylate water reducer, that is, first unsaturated anhydride and unsaturated primary amine are synthesized at a certain temperature into a small unsaturated primary amine. monomer, and then react it with small organic molecules containing epoxy groups and halogen groups to obtain quaternary ammonium salt unsaturated monomers, and finally introduce the unsaturated quaternary ammonium salts into polycarboxylic acid molecules as the third monomer In the structure, the obtained product has good functions such as reducing concrete viscosity and improving slump retention, but the method has disadvantages such as cumbersome steps, high raw material cost, and large production process pollution; Chinese patent document CN 100402457C discloses a polycarboxylate Acid concrete admixture, prepared by free radical copolymerization of alkyl (meth)acrylate monomer, specific polyalkylene glycol unsaturated macromonomer and unsaturated acid monomer, this method introduces a hydrophobic The third monomer alkyl acrylate, the resulting product has excellent cement dispersibility and can reduce the yield stress and viscosity of concrete, but this method has the disadvantages of high production cost, poor slump retention, and low viscosity reduction effect

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