New synthesis process of maleic anhydride monomethyl and dimethyl maleate concrete polycarboxylic acid slump retaining agent

Abstract

The invention provides a new synthesis process of a maleic anhydride monomethyl and dimethyl maleate concrete polycarboxylic acid slump retaining agent, the new synthesis process is characterized in that the process is polymerization of maleic anhydride monomethyl and dimethyl maleate and polyoxyethylene ether under effect of an initiator and a redox agent, the initiator is hydrogen peroxide; and the process is simple and easy to operate. The polymerization process is short, and production efficiency is high. The maleic anhydride monomethyl and dimethyl maleate concrete polycarboxylic acid slump retaining agent can be synthesized at normal temperature, and can also be heated and synthesized. The polymerization process has the advantages of flexible selection of temperature and low production cost. A polymerization drop solution is prepared only by use of deionized water to dissolve vitamin C, only needing dropwise addition, preparation operating labor burden of an operator can be reduced, the preparation is single, and has small error probability, and a basis for stable product quality is provided from operational aspects.

Description

technical field [0001] The invention relates to the field of concrete polycarboxylate slump-retaining agent, in particular to a new process for synthesizing the concrete polycarboxylate slump-retaining agent of maleic anhydride monodimethyl maleate. Background technique [0002] Compared with traditional high-efficiency superplasticizers, polycarboxylate high-efficiency superplasticizers that have been developed and gradually improved in recent decades have the characteristics of high water-reducing rate, low dosage in concrete, good slump-preserving effect, and flexible molecular structure design. It is favored and respected by the majority of concrete technology, production, and construction engineering technicians, so it is popularized and applied very quickly. However, in the face of the shortage of natural high-quality resources such as cement, sand, and stone, one of the main raw materials for concrete, a large number of substitutes are used; in order to solve environm...

AI Technical Summary

Problems solved by technology

First, the addition of organic retarders and inorganic retarders cannot fundamentally solve the problem of rapid loss of concrete slump. If the cement is not suitable, it will not only fail to increase the slump retention capacity of concrete, but will also cause false setting or Non-condensing, reducing the quality of concrete and affecting the construction progress

And the combination of organic retarder and polycarboxylate high-efficiency water reducer will easily make the admixture corrupt and deteriorate in a high temperature environment, affecting the performance of the admixture

Second, adding concrete high-efficiency water-reducing agent several times during concrete production and construction, or adding polycarboxylate high-efficiency water-reducing agent to reshape concrete before construction can restore the better working performance of concrete and make concrete have good fluidity However, adding polycarboxylate high-efficiency water-reducing agent for many times increases the amount of admixture and water, which not only increases the cost of concrete, but also causes bleeding and segregation of concrete, which destroys the uniformity of concrete and makes each part of concrete There is a large difference in the strength of the concrete, which reduces the compressive and flexural strength of concrete

Repeated addition of polycarboxylate high-efficiency water reducer solution can easily change the water-cement ratio and air content of concrete, reduce the impermeability of concrete, and increase the difficulty of concrete construction quality control

Third, the implementation of the post-mixing method has improved the performance of concrete, but it also cannot fundamentally solve the problem of increasing the slump retention capacity of concrete.

Ethylene oxide and propylene oxide are high-risk substances, flammable and explosive, and the safety risk of esterification synthesis is high, so the cost of esterification synthesis is high, and the cost of polymerizing polycarboxylic acid slump inhibitors with them is high, and the polymerization process is relatively complicated

The cost of the terminal product compounded by polymeric slump retaining agent and polycarboxylate superplasticizer is high