155results about How to "The synthesis process is easy to control" patented technology

The invention relates to a method for directly synthesizing a pure solid high-performance polycarboxylate water-reducer in one step, belonging to the field of water-reducers. According to the method, the pure solid high-performance polycarboxylate water-reducer is prepared by taking an acrylic compound and unsaturated polyoxyethylene ether as polymerization reaction monomers, adding a molecular weight regulator and carrying out free-radical polymerization reaction under the action of an initiator and under a solvent-free environment. The method disclosed by the invention is strong in controllability, high in polymerization degree, low in cost, environment-friendly and pollution-free, achieves the purpose of preparing the absolutely anhydrous pure solid polycarboxylate water-reducer by bulk polymerization, not only has the fluidity and holding property of cement paste, cement adaptability and concrete application performance which are similar to those of a polycarboxylate water-reducer prepared from a common solution by polymerization and can be prepared into any concentration of solution according to actual demands as the pure solid high-performance polycarboxylate water-reducer prepared by direct polymerization is an anhydrous pure solid, but also is free of postprocessing working procedures, such as heat drying or solvent separation and is more convenient to transport, saved in transport cost and favorable in market competitiveness and application prospect.

This invention relates to a method for preparing a star-shaped polycarboxylate superplasticizer by the first esterification step with polyol and (meth)acrylic acid as main reactants and the second polymerization step. In the first step, the star-shaped polymerizable active ends were synthesized by esterification between polyol and (meth)acrylic acid in the presence of catalyst. In the second step, the final star-shaped polycarboxylate superplasticizer was prepared by radical polymerization among the product obtained in first step, unsaturated polyoxyethylene ethers, molecular weight regulator and unsaturated carboxylic acid in the presence of initiator. The production process of this invention exhibits some characteristics including simple, easily controllable, high polymerization degree, low cost and pollution free. The star-shaped molecular structure of polycarboxylate superplasticizer can be achieved through synthesizing active “core” by esterification and “arm” by radical polymerization. It showed better cement paste fluidity and fluidity retention, which manifested as better adaptability to cement and application performance in concrete, than both traditional linear and comb-shaped polycarboxylate superplasticizer at common or lower dosage.

The invention discloses a synthesis method of a polycarboxylic acid high-performance water reducing agent of a star-like structure, belonging to the field of a water reducing agent. According to the synthesis method, polybasic alcohol, (methyl) acrylic acid, a polyethylene glycol compound and the like are used as esterification raw materials, and the polycarboxylic acid high-performance water reducing agent of the star-like structure is prepared through a sequential esterification and polymerization method, i.e., the (methyl) acrylic acid and the polybasic alcohol are used as reactants, a star-like polymerizable active end is prepared through esterification reaction under the action of a catalyst, and then the polycarboxylic acid high-performance water reducing agent is prepared from the star-like polymerizable active end and esterification macromolecule, a molecular weight regulator and an unsaturated carboxylic acid monomer under the action of an initiator through free radical polymerization reaction. The synthesis method has the advantages of simplicity, easiness in control, high polymerization degree, low cost, no pollution, capability of realizing the polycarboxylic acid high-performance water reducing agent of the star-like structure connected with a plurality of polycarboxylic acid molecules, and more superior cement paste fluidity and holding capacity, good cement adaptability and concrete application performance compared with the conventional linear and comb-shaped polycarboxylic acid water reducing agent in the case of normal and low added amount.