A kind of silane coupling agent modified polycarboxylate water reducer and preparation method thereof

Abstract

The invention discloses a polycarboxylate water reducer modified by a silane coupling agent and a preparation method thereof. It belongs to the field of cement additives. Add a certain amount of acrylic acid to the polyether macromonomer solution, stir evenly, then add a silane coupling agent containing a double bond, the stirred solution is clear, continue to stir; continue to keep stirring, add oxidant, initiator solution and small Monomer solution; after stirring and aging for 1-2 hours, add liquid caustic soda to neutralize, stabilize the pH value at 6, and then add a silane coupling agent without double bonds to obtain a silane coupling agent-modified polycarboxylate superplasticizer finished product. The synthesis of the present invention introduces a functional group containing a siloxane structure into the main chain of the polycarboxylic acid molecule to provide an anchoring ability for the branched chain of the comb-shaped polycarboxylate superplasticizer to chemically bond and strongly interact with the gelling material particles , the increase of the anchoring capacity can significantly enhance the adaptability and slump retention of the water reducer, and expand the use of the water reducer in the field of mineral powder dispersion to a certain extent.

Description

technical field [0001] The invention relates to a polycarboxylate water reducer modified by a silane coupling agent and a preparation method thereof, belonging to the field of cement additives. Background technique [0002] The setting time, fineness, specific surface area and particle distribution of cement all affect the bleeding performance of concrete. The setting time of cement directly determines the settlement time of cement particles. The longer the setting time, the easier it is for the concrete to bleed; the coarser the fineness of the cement, the smaller the specific surface area, and the C 3 If the A content is too small, the cement hydration amount in the early stage will be less, and the less hydration products will not be enough to block the capillary pores in the concrete, so that the internal moisture will easily move from bottom to top, and the concrete will bleed more seriously. In addition, when the sand aggregate contains more mud, it will seriously aff...

AI Technical Summary

Problems solved by technology

The dispersion of cement particles is caused by weak interactions such as electrostatic repulsion, steric repulsion, and wetting of water molecules. During the hydration process, polycarboxylic acid molecules will lose their adsorption capacity and water-reducing effect as the microscopic conditions change. reduce

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