Poly carboxylic acid series super plasticizer and its preparing method

Abstract

The present invention is serial polycarboxylic acid super plasticizers and their preparation process, and belongs to the field of concrete admixture technology. The super plasticizer is prepared with acrylic acid, methoxy polyglycol-1000 and sodium vinyl sulfonate, and through the esterification of acrylic acid and methoxy polyglycol-1000 in water bath to prepare intermediate polyglycol acrylate, and the subsequent free radical polymerization of polyglycol acrylate, sodium vinyl sulfonate and acrylic acid under the action of initiator in water solution. The preparation process has easily controlled condition, simple operation, no pollution, low cost and other features. The product of the present invention may be used as concrete super plasticizer suitable for different kinds of cement.

Description

Technical field: [0001] The invention belongs to the technical field of concrete admixtures, in particular to a concrete superplasticizer and a preparation method thereof. Background technique: [0002] With the development of modern concrete technology, the strength and durability of concrete continue to increase, and the water-binder ratio of concrete will become smaller and smaller. In engineering, the water-binder ratio is less than 0.25, the compressive strength exceeds 100MPa and can maintain good fluidity. The application is gradually increasing; in addition, with the development of modern architectural design and construction technology, concrete is required to develop in the direction of high strength, light weight and construction fluidization. High-performance superplasticizer is a key material for obtaining high-performance concrete. In addition to its higher water-reducing effect, it is also required to control the slump loss of concrete and better solve the air...

AI Technical Summary

Problems solved by technology

[0006] It can be seen that the current polycarboxylate superplasticizers and their preparation methods almost all use polyethylene glycol as the grafted side chain to carry out the synthesis of superplasticizers, and the use of polyethylene glycol as the grafted side chain needs to control its 50 % of the esterification rate, the esterification conditions are difficult to control, and it is easy to generate part of maleic anhydride polyethylene glycol diester or meth (acrylic acid) polyethylene glycol diester during the esterification process, which will produce cross-linking in the polymerization process. Linked to obtain body-shaped polymers, resulting in fluctuations in the performance and performance stability of polycarboxylic acid superplasticizer products; Small (between 1 and 1.5), so to increase the yield of esterification, an oil bath or electric heating mantle is usually used as a heating device, and organic solvents such as toluene, benzene, ethyl acetate, and cyclohexane are used as water-carrying agents to form a constant temperature with water. The boiled matter then takes out the water generated by the esterification reaction. The organic solvent has certain toxicity and special odor, and will increase the operation of recovering the solvent; in addition, in the polymerization reaction, the feeding method of the initiator ammonium persulfate or sodium persulfate is The synthesis process is cumbersome by adopting the method of dropping or batch feeding

[0007] It can be seen that the current domestic synthesis methods of polycarboxylic acid superplasticizers have certain defects in the selection of raw materials. Polyethylene glycol is used as the grafted side chain, and the synthesis conditions are difficult to control. Organic solvents with certain toxicity and special odor are used as water-carrying agents, which do not conform to the development trend of green production of high-efficiency concrete superplasticizers, and once polyethylene glycol diester is produced, the performance and performance of superplasticizers will inevitably be stable. In addition, the feeding method of the initiator ammonium persulfate or sodium persulfate adopts the method of dropping or batch feeding, and the synthesis process is cumbersome, which is not conducive to industrial production and application

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