Styrene-butadiene rubber (SBR) is the most widely used synthetic rubber and can be produced by the copolymerization of butadiene (75%) and styrene (25%) using free radical initiators. A random copolymer is obtained. The microstructure of the polymer is 60%–68% trans, 14%–19% cis, and 17%–21% 1,2-. Wet methods are normally used to characterize polybutadiene polymers and copolymers. Solid-state NMR provides a more convenient way to determine the polymer microstructure.
Currently, more SBR is produced by copolymerizing the two monomers with anionic or coordination catalysts. The formed copolymer has better mechanical properties and a narrower molecular weight distribution. A random copolymer with ordered sequence can also be made in solution using butyl-lithium, provided that the two monomers are charged slowly. Block copolymers of butadiene and styrene may be produced in solution using coordination or anionic catalysts. Butadiene polymerizes first until it is consumed, then styrene starts to polymerize. SBR produced by coordination catalysts has better tensile strength than that produced by free radical initiators.
The main use of SBR is for tire production. Other uses include footwear, coatings, carpet backing, and adhesives.
Feature
Wear resistance, aging resistance, water resistance and air tightness are better than natural rubber, while adhesion, elasticity and deformation calorific value are lower than natural rubber. Styrene butadiene rubber has excellent comprehensive properties. It is the largest variety of synthetic rubber, and its output accounts for 60% of synthetic rubber. About 87% of the styrene butadiene rubber production capacity in the world uses emulsion polymerization. Generally speaking, styrene butadiene rubber mainly refers to emulsion polymerized styrene butadiene rubber. Emulsion polymerized styrene butadiene rubber also includes high temperature emulsion polymerization of butadiene styrene and low temperature emulsion polymerization of cold butadiene.
Use
Used for making sponge rubber, impregnated fiber and fabric, also used as adhesive, coating etc.
Post time: Mar-10-2022