A kind of synthetic method of polycarboxylate water-reducer containing siloxyl group

Abstract

The invention provides a method for synthesizing a polycarboxylate water reducer containing siloxy groups, which comprises the following steps: S1: adding maleic anhydride and a silane coupling agent, at a reaction temperature of 0°C to 10°C , the reaction is complete to generate silicone oligomers; S2: Add the silicone oligomers, organic solvent and initiator, and add unsaturated carboxylic acid monomer dropwise at a uniform speed. After the reaction is complete, after treatment, the target product can be obtained. The polycarboxylate superplasticizer containing silaneoxy group exhibits excellent retarding and plastic preservation effect, and because of the use of an organic solvent system, it avoids the formation of silane coupling agent after hydrolysis of silicon methoxy or silicon ethoxy The silanol condensation reaction occurs, thereby avoiding the adverse effect that ordinary polycarboxylate superplasticizers cannot effectively function in precast concrete. Both the initial performance and the time-lapse performance of the polycarboxylate water reducer containing siloxy groups are significantly better than commercially available common polycarboxylate water reducers.

Description

Technical field[0001]The invention belongs to the technical field of building admixtures, and in particular relates to a method for synthesizing a polycarboxylic acid water reducing agent containing siloxy groups.Background technique[0002]Polycarboxylic acid type water reducer is the third generation concrete admixture after lignosulfonate type water reducer and naphthalene type water reducer. It is currently used in various industrial buildings, civil buildings, roads and bridges at home and abroad. Widely used; polycarboxylate water-reducing agent has become the most widely used and the largest amount of building admixture, in some engineering fields, such as nuclear power engineering, high-strength concrete (C60 and above), ultra-high-strength concrete (C80 and above) ), high-speed railway engineering, high-rise / super high-rise pumping and other concrete applications play an irreplaceable role.[0003]In the prior art, the ratio of reactants, reaction conditions and synthesis proce...

AI Technical Summary

Problems solved by technology

In addition, in the existing synthesis process, when organosilicon compounds are applied to the synthesis of polycarboxylate superplasticizers, it is impossible to completely avoid the hydrolysis reaction of the silicon-oxygen bond of the silane coupling agent under acidic water phase conditions, so that it is impossible to avoid the hydrolysis reaction. The generated silanol condensation reaction affects the performance of the water reducer

Images