Method for synthesizing solid polyacrylic-series water reducing agents by aid of microwaves at one step

Abstract

The invention provides a method for synthesizing solid polyacrylic-series water reducing agents by the aid of microwaves at one step. The method includes adding unsaturated polyoxyethylene ether into a reactor with a stirring device; melting the unsaturated polyoxyethylene ether under microwave conditions, then sequentially adding chain transfer agents, unsaturated carboxylic acid and initiators into the reactor; stirring the unsaturated polyoxyethylene ether, the chain transfer agents, the unsaturated carboxylic acid and the initiators at the temperatures of 20-70 DEG C for 10-30min, and then stopping the polyoxyethylene ether, the chain transfer agents, the unsaturated carboxylic acid and the initiators from reacting with one another; cooling reaction products of the polyoxyethylene ether, the chain transfer agents, the unsaturated carboxylic acid and the initiators until the temperatures of the reaction products reach the room temperature so as to obtain the solid polyacrylic-series water reducing agents. The method has the advantages that microwave equipment with a stirring function is utilized in procedures for preparing the solid polyacrylic-series water reducing agents, so that various materials which participate in reaction can be uniformly mixed with one another without water or other organic solvents, and can completely react with one another, and the solid polyacrylic-series water reducing agents with excellent performance and the content nearly equal to 100% can be obtained under the conditions of specific microwave reaction frequencies, reaction power and reaction time.

Description

technical field [0001] The invention belongs to the technical field of polycarboxylate water reducer for concrete, and in particular relates to a method for one-step synthesis of solid polyacrylic acid water reducer by using microwaves. Background technique [0002] Polyacrylic acid-based water reducer has become one of the necessary components of concrete because of its high water-reducing rate and excellent slump retention. However, the current polyacrylic acid-based water-reducer is usually an aqueous solution with a content of 10% to 50%. The content of active ingredients is low. On the one hand, this polyacrylic acid water reducer in the form of aqueous solution will greatly increase the transportation cost. On the other hand, it also limits its application in dry powder mortar and narrows the application range of polyacrylic acid water reducer. [0003] Patent CN1919772A reports a preparation method of powder polycarboxylate water reducer, which obtains polycarboxylate...

AI Technical Summary

Problems solved by technology

This method can obtain solid polycarboxylate superplasticizers with high solid content, but has the following defects: 1. Organic solvents are used in the reaction process, which increases the burden on the environment; 2. Polycarboxylate superplasticizers must be neutralized by alkali , centrifugation and other steps to obtain solid products, the process is complicated and not conducive to industrial production

Secondly, the polyethers used in this patent are isopentenyl alcohol polyoxyethylene ether, isobutenyl alcohol polyoxyethylene ether and allyl alcohol polyoxyethylene ether. Most of the currently commercially available polyethers are solid at room temperature. In this patent It is difficult to mix it into a uniform paste under the ratio of raw materials. Spreading this unevenly mixed paste raw material on a flat plate without stirring during the reaction will lead to different batches of reactions. Poor repeatability, not conducive to industrial production

Images