A method for preparing carboxylated styrene-butadiene rubber by emulsion polymerization

Abstract

The invention relates to a method for preparing carboxylated styrene-butadiene rubber by emulsion polymerization. Styrene, an emulsifier, a regulator, and an initiator are added to a polymerization kettle, and after adding butadiene, emulsion polymerization is carried out under stirring. In the late stage of the reaction, Add unsaturated carboxylic acid and / or its anhydride of unsaturated carboxylic acid into the polymerization tank. The carboxylated styrene-butadiene rubber prepared by the method of the present invention has low gel content, controllable binding acid index, has a double-layer molecular structure, and is easy to form a three-dimensional network shape structure during processing, and has good physical and mechanical properties of rubber products, and is easy to process. After the Mooney viscosity increases, the degree of crosslinking of the finished product is good, especially the elongation at break is significantly improved.

Description

A method for preparing carboxylated styrene-butadiene rubber by emulsion polymerization technical field The invention relates to a method for preparing carboxylated styrene-butadiene rubber by emulsion polymerization, in more detail, a method for producing surface-grafted carboxylated styrene-butadiene rubber raw materials by emulsion polymerization. Background technique At present, there are many methods for preparing styrene-butadiene rubber by emulsion method, such as continuous polymerization method and batch polymerization method. CN200710042967.6 discloses a styrene-butadiene emulsion and its preparation method and application. The preparation method comprises the following steps: carboxylic acid monomer, butadiene monomer, (methyl) styrene monomer, molecular weight regulator, emulsifier The aqueous solution of the mixture of the initiator and the initiator is subjected to free radical emulsion copolymerization, and the reaction time is 3 to 10 hours. The pH of the ...

AI Technical Summary

Problems solved by technology

The current styrene-butadiene rubber is formed by binary copolymerization of butadiene and styrene. The terpolymerized carboxylated styrene-butadiene rubber has a high gel content due to the structure of more ether bonds and unsaturated bonds in the main chain. The physical and mechanical properties of the product after processing are poor, and the characterization data is unstable. The existing method to change the properties of styrene-butadiene rubber is to add polymers containing carboxyl components to the mixing formula to achieve the purpose of improving the physical and mechanical properties of styrene-butadiene rubber products. Complexity, many equipment requirements, pollution, high energy consumption, uneven mixing of final products, unstable physical and mechanical properties, and limited applications