Preparation method of polycarboxylate water reducer with intensively-distributed carboxyl groups and high water reduction performance, product thereof, and application of product

Abstract

The invention provides a preparation method of a polycarboxylate water reducer with intensively-distributed carboxyl groups and high water reduction performance. The preparation method comprises the following steps: adding a low molecular weight unsaturated carboxylic acid compound, adding a catalyst, and reacting to obtain an unsaturated carboxylic acid polymer; adding the unsaturated carboxylic acid polymer, an unsaturated polyether monomer and an unsaturated sulfonate or polyether monomer unsaturated carboxylate, adding distilled water, mechanically stirring for fully dissolving to form a clarified solution, adding an initiator, adding an aqueous solution of a chain transferring agent in a dropwise manner at a constant speed, continuously reacting after the dropwise addition ends, and stopping the reaction to obtain polycarboxylic acid with intensively-distributed carboxyl groups; and adding an alkali solution to the polycarboxylic acid with intensively-distributed carboxyl groups, neutralizing to the pH value of 5-7, and adding water to dilute in order to obtain the product. The invention also provides the polycarboxylate water reducer prepared through the method, and an application of the polycarboxylate water reducer in concrete. The polycarboxylate water reducer has better initial fluidity and ageing fluidity than common polycarboxylate water reducers, and has very good application prospect.

Description

technical field [0001] The invention belongs to the field of concrete admixtures, and in particular relates to a preparation method, product and application of a polycarboxylate water-reducer with concentrated carboxyl groups and high water-reducing performance. Background technique [0002] Polycarboxylate superplasticizer, also known as superplasticizer, was first patented by Kao Corporation of Japan in the 1980s. After rapid development, it has basically replaced naphthalene-based superplasticizers in developed countries such as Europe, America and Japan. And aliphatic superplasticizers, the market share of domestic polycarboxylate superplasticizers has exceeded 50%, and is expected to reach 80% of the total amount of concrete admixtures within a few years. [0003] Polycarboxylate water reducers are divided into ester monomer water reducers and ether monomer water reducers. Among them, the raw materials used in ether monomer water reducers are unsaturated alcohol polyeth...

AI Technical Summary

Problems solved by technology

[0004] In the prior art, most of the literature reports on the synthesis of polycarboxylate superplasticizers using unsaturated alcohol polyethers as raw materials are one-step methods, that is, under certain reaction conditions, unsaturated alcohol polyethers and unsaturated carboxylic acids are directly copolymerized by free radicals. Reaction, synthesis of polycarboxylate water reducer, this type of method can not control the arrangement and distribution of carboxyl and polyether side chains, only the proportion of functional groups can be controlled, and the unsuitable distribution and arrangement of carboxyl and polyether side chains may bring polycarboxylate Negative Effects on Superplasticizer Performance