Preparation method for gas making barrier of anti-adsorption type polycarboxylic acid water reducer

Abstract

The invention discloses a preparation method for a gas making barrier of an anti-adsorption type polycarboxylic acid water reducer. The preparation method comprises the following steps: 1) placing a polyether macromonomer and water at the bottom of a reactor, stirring until a solution has no obvious blocky or sheet-shaped materials, controlling the initial temperature to be not higher than 22 DEGC, and adjusting the pH to be equal to 8.5 with liquid alkali; 2) after 5 min, simultaneously dropwise adding a reducing chain transfer complex agent solution and an oxidant solution, and controllingthe dropping time to be a h; 3) after another 5 min, dropwise adding a small monomer solution, and controlling the dropping time to be a to 0.5 h; 4) then after 20 min, dropwise adding a liquid alkalisolution, controlling the dropping time to be a+0.5 h; 5) at later reaction, when the reaction temperature exceeds 35 DEG C, opening cooling water to circulate, and opening an air pump and introducing micro pores of which the apertures are 0.5 to 2 mm to the reaction kettle; and 6) after dropwise adding the liquid alkali solution, carrying out heat preservation for 0.5 to 2.0 h, stopping stirring, thus obtaining finished product mother liquor. The polycarboxylic acid water reducer disclosed by the invention has strong adaptability, can resist burying or physical adsorption of strong adsorbates, and obviously improves the slump retention, cohesiveness and plasticity retention of fresh concrete.

Description

technical field [0001] The invention relates to the technical field of a polycarboxylate water reducer, in particular to a method for preparing an anti-adsorption polycarboxylate water reducer for gas-forming barrier. Background technique [0002] At present, there are many factors affecting the working state of concrete, such as sand, cement, and mineral admixtures; correspondingly, concrete admixtures have increased significantly. C 3 A. Clay minerals are layered hydration products, the layer is negatively charged, and the end of the layer is positively charged. Because the end of the layer is positively charged, due to electrostatic adsorption, some negatively charged short-chain branches -COOH, - in the PC structure CONH 2 、-SO 3 Na is easily adsorbed at the end of the layer, causing the long side chain (polyether) of PC to enter the interlayer structure, and the O of the long side chain polyether molecule forms a hydrogen bond with the H of the clay layer, making it ...

AI Technical Summary

Problems solved by technology

The double-dropping mode generally puts the oxidizing agent directly at the bottom of the kettle, and the reducing agent and the small monomer solution are added dropwise in batches. This traditional dropping method does not consider the half-life of the oxidizing agent, and the reactivity is poor. This method will have a certain probability of normal temperature When the process fails to trigger the temperature rise normally, during the double dropping process, the pH value of the reaction solution tends to be less than 3 in the later stage of the dropping, and the triggering efficiency decreases