Green preparation method of slow-release polycarboxylic-acid high-performance water reducing agent

Abstract

The invention relates to a green preparation method of a slow-release polycarboxylic-acid high-performance water reducing agent, which comprises the following steps: firstly, dissolving unsaturated polyethenoxy ether in water, adding an oxidant solution, and evenly stirring; then, respectively and dropwisely adding a reducer/chain-transfer agent mixed solution and a comonomer solution, and polymerizing; and finally, adding an alkaline regulator to neutralize and age the solution, thereby obtaining the slow-release polycarboxylic-acid high-performance water reducing agent. In the invention, hydrogen on the terminal hydroxyl group of the original unsaturated polyethenoxy ether is substituted by an allyl group containing unsaturated bond, so that the terminal group of methoxypolyethylene glycol is converted from the original active hydroxyl group into the inert methoxy group at present; and thus, the byproducts of the copolymerization product are greatly reduced, and the molecular weight distribution is narrow, so that the synthesized water reducing agent has the advantages of high water reduction rate and slump resistance. The redox system with low activation energy is used for initiating the monomer copolymerization, so that the polymerization can be implemented at normal temperature, thereby implementing the production of the product by a no heat source method, simplifying the production equipment and lowering the energy consumption and cost.

Description

Technical field [0001] The present invention belongs to the field of concrete exterior agent technology in building materials. It specifically involves a high -performance water reducing agent of a mild release polycarboxylic acid system. It specially involves a high -performance water reduction reduction of polycarboxylic acids that does not use organic solvents and does not use organic solvents.Green preparation method of the agent. Background technique [0002] Concrete is the world's largest and most widely used building material.With the comprehensive development of my country's infrastructure construction, the amount of concrete in railway, highway, bridge and other buildings has greatly increased, and the requirements for modern concrete technology have become higher and higher.High -performance concrete with high water reduction rate, low collapse, high strength, and high -strength characteristics is the direction of concrete development.In order to adapt to the developme...

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Problems solved by technology

Among them, the two-step process has a high reaction temperature and a long reaction cycle. In order to improve the esterification rate of the esterification reaction, an organic solvent is also used as a water-carrying agent, which not only consumes high energy, but also causes new pollution for its purification and recovery; Compared with the two-step process, although the production cycle is short and the temperature is low, the production energy consumption is greatly reduced, but heating equipment is still required, which cannot meet the requirements of simple production, and the use of coal and other fuels will also cause environmental pollution. Pollution; In addition, the products of the current one-step process still cannot meet the high water-reducing rate and requirements under low-concentration conditions, and the slump retention of concrete is not as good as the products of the two-step process

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