Preparation method of salt-tolerant amphoteric polycarboxylate high-performance water reducer

Abstract

The invention relates to a preparation method of a salt-tolerant amphoteric polycarboxylic acid high-performance water reducer. The present invention uses unsaturated cationic quaternary ammonium salt monomers, unsaturated small monomers, unsaturated initiators, transition metal complexes, etc. as main raw materials, and synthesizes salt-tolerant amphoteric polycarboxylic acids by self-polymerization and then graft copolymerization. High-performance water reducer, that is, using unsaturated cationic quaternary ammonium salt monomer as reactant, atom transfer radical polymerization (ATRP) in the system composed of unsaturated initiator and transition metal complex to obtain cationic macromonomer, and then It is prepared by free radical graft copolymerization with small unsaturated monomers under the action of initiator and chain transfer agent. The invention is based on the principle of traditional radical polymerization and atom transfer radical polymerization to carry out innovative design and synthesis of molecular structure. The prepared water reducer has the advantage of maintaining good dispersibility under high-concentration salt conditions, and the process is simple and reliable. control, energy saving and environmental protection, and realize the cationic substitution of traditional polyether side chains.

Description

technical field [0001] The invention relates to the technical field of a water reducer for cement concrete, in particular to a salt-tolerant amphoteric polycarboxylic acid obtained by self-polymerizing an unsaturated cationic quaternary ammonium salt monomer to obtain a cationic macromonomer and then graft-copolymerized The specific preparation method of high-performance water reducer. Background technique [0002] Polycarboxylate high-performance water reducer has the advantages of low dosage, high water reducing rate, good slump retention, and strong designability of molecular structure, and has become an important part of concrete admixture. Commonly used polycarboxylate superplasticizers have main chains of -COOH, -SO 3 H and other adsorption groups, the side chain is a comb structure polymer of polyether, but the spatial configuration of the traditional comb structure polycarboxylate superplasticizer is easily affected by the high concentration of salt ions in cement o...

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Problems solved by technology

However, the amphoteric polymer prepared by the above-mentioned invention has not shown good dispersion and dispersion stability in the high-concentration salt cement system due to the low proportion of the cationic component contained in the above-mentioned synthesis method, and the above-mentioned synthesis method has a certain degree of inadequacy. , most of the inventors use traditional polyether as the reaction raw material to prepare the target product, and have not really realized the innovation of molecular structure. chain (each link of the side chain is a cationic structure) replaces the traditional polyether structure, which severely limits the theoretical and technological development of amphoteric water reducers and their application in the field of cement concrete.

Therefore, there is an urgent need for a concrete water-reducing agent with a new molecular structure, which not only has the characteristics of both sexes and excellent functions in a balanced manner, but also can ensure a simple and controllable preparation process and a wide range of preparation raw materials. There are no relevant reports on this aspect of work

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