Preparation method of high carboxyl density polycarboxylic acid water reducing agent with long and short branched chains

Abstract

The invention provides a preparation method of a high carboxyl density polycarboxylic acid water reducing agent with long and short branched chains. The preparation method comprises the following steps: (1) adding 3000 molecular weight polyether macromonomers, 1200 molecular weight polyether macromonomers and water at a certain ratio in a reaction kettle, and stirring and heating until dissolving;2) controlling the temperature to 45-50 DEG C, and starting to add a certain amount of hydrogen peroxide; (3) after 5 min, sequentially starting to dropwise add a solution B and a solution A, whereinthe solution A starts to be dropwise added within 10 min after the addition of the hydrogen peroxide, the dropwise adding time of the solution A is a hours, the dropwise adding time of the solution Bis a+0.5 hours, the solution A consists of acrylic acid, unsaturated sulfonate and water at a certain ratio, and the solution B consists of ascorbic acid, a phosphate monomer, a chain transfer agentand water; and (4) after the dropwise adding is completed, maintaining temperature constant, curing for b hours, and when the temperature of the reaction solution is lower than 30 DEG C, slowly addinga certain amount of neutralizer, and supplementing water to 1000 parts, thereby obtaining the high carboxyl density polycarboxylic acid water reducing agent with long and short branched chains.

Description

technical field [0001] The invention belongs to the technical field of building materials and relates to the field of concrete admixtures, in particular to a preparation method of a polycarboxylate water reducer with high carboxyl density long and short branched chains. Background technique [0002] Water reducer is one of the necessary components for preparing high performance concrete, and it is used more and more widely. At present, the molecular weight of the polyether macromonomer used in most polycarboxylate superplasticizers is around 2400, which has reached a bottleneck in the development level. It is necessary to increase the research and use of other polyethers with different molecular weights. The problem of the coordinated use of molecular weight polyethers is also to be explored. [0003] Two polyether macromonomers with large molecular weight differences are used to obtain a side chain structure with alternate distribution of long and short chain branches. Af...

AI Technical Summary

Problems solved by technology

At present, the molecular weight of the polyether macromonomer used in most polycarboxylate superplasticizers is around 2400, which has reached a bottleneck in the development level. It is necessary to increase the research and use of other polyethers with different molecular weights. The problem of the coordinated use of molecular weight polyethers also needs to be explored