Method for synthesizing polycarboxylic acid concrete high-performance water reducing agent

Abstract

The invention discloses a method for synthesizing polycarboxylic acid concrete high-performance water reducing agent, which comprises two steps of etherification and polymerization, wherein in the step of etherification, methoxypolyethylene glycol (MPEG) and vinyl methacrylate serving as main reaction raw materials are added with a polymerization inhibitor and a catalyst to undergo the etherification, and after the etherification is finished, softened water is used for dilution to achieve a 73 percent concentration, the pH value is adjusted to 3.5 to 4.0, mercaptopropionic acid is added, and discharging is performed after the temperature is reduced to 43 DEG C to obtain an etherified monad; and in the step of polymerization, a proper amount of softened water are added in a reaction kettle, the etherified monad and the softened water are transferred into two overhead tanks in a ratio of 20:8 respectively, a metered initiator (ammonium persulfate) in an amount of 1.7 percent by mass of the etherified monad is added into the softened water, the etherified monad and the softened water added with the metered initiator are dripped into the reaction kettle at a constant speed, the temperature is kept for 4 hours after the dripping is finished, the temperature is reduced to be between 40 and 45 DEG C, 30 percent sodium hydroxide is added, the pH value is adjusted to between 6.0 and 8.0, and after the polymerization, the polycarboxylic acid concrete high-performance water reducing agent is obtained.

Description

technical field [0001] The invention relates to a high-performance water-reducer for concrete, in particular to a synthesis method of a novel polycarboxylate high-performance water-reducer for concrete. technical background [0002] The research on traditional lignosulfonate, naphthalene, melamine and other water reducers began in the 1960s. The research and application in various countries have become increasingly mature and perfect, and the corresponding structure and performance development changes little; The research and development of polycarboxylate water reducers began in the late 1980s and early 1990s. Its molecular structure can have many changes, and it can be directly synthesized to obtain water reducers with different properties. Its dispersion ability is much higher than that of naphthalene. It can meet the requirements of concrete slump loss control, and can meet the requirements of various properties of concrete in construction projects at the same time, and ...

AI Technical Summary

Problems solved by technology

[0011] The research and development of new polycarboxylate superplasticizers in my country is just in its infancy, and the performance of most new products is far from meeting the actual needs. There are widespread problems in practical applications, which affect the widespread application.

Polycarboxylate superplasticizers are sensitive to the dosage during application. If the dosage is too low, the cement particles cannot be fully dispersed and the concrete slump is small. If the dosage is too large, the cement particles will be easily dispersed. The water retention of concrete is not good, the phenomenon of segregation and bleeding is serious, and even the slurry compaction is separated from water, so it is difficult to control during construction.