Styrene-butadiene rubber (SBR): properties and applications / Articles

Styrene-butadiene rubber (SBR) is the most widely used and mass-produced general-purpose synthetic rubber in the world. It is a copolymer of butadiene (CH₂=CH–CH=CH₂) and styrene (C₆H₅–CH=CH₂). In terms of global production volume, SBR ranks first among all synthetic rubbers and is the primary material for the tyre industry. Thanks to excellent abrasion resistance, good physical and mechanical properties and affordable pricing, SBR has found widespread application in tyres, rubber technical products, footwear and many other goods.

Chemical Structure and History

Styrene-butadiene rubber is a random copolymer of butadiene and styrene. The bound styrene content in commercial grades is typically 10–25% (the most common grades contain about 23–25% styrene). The low-temperature flexibility of the rubber depends on the bound styrene content: rubbers with 8–10% styrene are more frost-resistant than natural rubber.

The history of SBR began in Germany in the 1930s when chemists Walter Bock and Eduard Tschunkur of IG Farben first developed an emulsion polymerisation process, producing the synthetic rubber Buna-S. In the 1960s, Firestone and Phillips began commercial production of solution SBR grades. In the USSR, industrial production of SBR was established in the post-war years and continues to develop to this day.

Production Methods

Depending on the polymerisation technology, two main types of styrene-butadiene rubber are distinguished:

Emulsion SBR (e-SBR) — produced by free-radical emulsion polymerisation of butadiene and styrene. The process can be carried out at 50–60 °C (hot emulsion polymerisation) or at about 5 °C (cold emulsion polymerisation). The cold process provides better abrasion resistance and dynamic properties.

Solution SBR (s-SBR) — produced by anionic polymerisation in a hydrocarbon solvent (hexane or cyclohexane) using butyllithium as an initiator. Solution grades offer improved flexibility, good resilience and low rolling resistance, making them preferred for high-performance tyres.

Grades and Classification

In Russia, styrene-butadiene rubbers are produced under the SKS brand with a numerical designation indicating the bound styrene content. Main grades include:

SKS-30ARK — non-oil-extended rubber with 30% styrene content, contains antioxidants. Mooney viscosity — 45–57.
SKS-30ARKM-15 — oil-extended emulsion rubber produced by low-temperature emulsion copolymerisation. Combines high elasticity with improved frost resistance and wear resistance.
SKS-30ARPD — rubber for cable and electrical industries with high dielectric characteristics. Tensile strength — not less than 26.5 MPa, elongation at break — not less than 575%. Bound styrene content — 22–25%.

Physical, Mechanical and Chemical Properties

Styrene-butadiene rubber possesses a unique combination of properties:

Abrasion Resistance. This is the key property of SBR — it can withstand repeated friction and wear without breaking down quickly, making it ideal for tyres and conveyor belts. SBR tyre treads are somewhat superior to natural rubber in abrasion resistance under summer conditions.

Elasticity. SBR is the only material that exhibits long-range elasticity. Elongation at break reaches 575% and more.

Physical and Mechanical Properties. Tensile strength is at least 26.5 MPa (265 kgf/cm²). Hardness can range from 35 to 100 IRHD.

Chemical Resistance. Carbon black-filled SBR vulcanisates are chemically resistant but swell in gasoline, benzene, toluene, mineral and vegetable oils. SBR is not resistant to oils, ozone and weathering.

Water Resistance and Gas Permeability. SBR vulcanisates are equivalent to natural rubber vulcanisates in water resistance and gas permeability.

Electrical Properties. SBR has good dielectric characteristics, allowing its use in the cable industry.

Advantages and Disadvantages

Key Advantages:

Excellent abrasion and wear resistance
Good physical and mechanical properties
Affordable price compared to natural rubber
Wide range of grades with various properties
Good processability

Main Disadvantages:

Low resistance to oils, ozone and weathering
Limited low-temperature flexibility (depends on styrene content)
Low green strength

Applications

Styrene-butadiene rubber finds wide application in various industries:

Tyre Industry. This is the main consumer of SBR — over 50% of total volume. SBR is used for passenger and truck tyre treads, sidewalls, and in blends with natural rubber and other elastomers.

Rubber Technical Products. Production of conveyor belts, drive belts, hoses, hoses, gaskets, seals and other technical products.

Footwear Industry. SBR is widely used for soles, heels and other shoe components.

Cable Industry. Special grades are used for insulation and sheathing of power and special cables.

Automotive Parts. Production of automotive seals, gaskets, trims and other components.

Consumer Goods. Manufacture of toys, sports equipment, mats and other consumer products.

Global Market

The global styrene-butadiene rubber market shows steady growth. In 2025, the market was valued at USD 11.95–14.39 billion. It is projected to reach USD 19.44–24.72 billion by 2034 at a CAGR of 3.86–5.56%.

The Asia-Pacific region dominates the market with a share of about 33%, driven by the growth of the tyre and automotive industries, especially in China. North America accounts for about 30% of the market, Europe — 24%, Latin America — 6%, and the Middle East and Africa — 5%.

Major SBR producers include Arlanxeo, Synthos, Trinseo, Kumho Petrochemical, JSR Corporation, LG Chem, Sinopec and PetroChina. In Russia, SBR is produced by Sibur (Nizhnekamsk, Togliatti), Voronezhsynthezkauchuk and others.

Synthetic rubber consumption in Russia grew by 19.8% in 2024 to 345,000 tonnes, while the import share decreased from 10% to 3%.

Conclusion

Styrene-butadiene rubber (SBR) is the most widely used and sought-after synthetic rubber in the world. Thanks to excellent abrasion resistance, good physical and mechanical properties and affordable pricing, it occupies key positions in the tyre industry, rubber technical products, footwear and cable products. The development of solution-grade technologies with improved characteristics and growing demand in the automotive industry ensure sustainable growth of the SBR market in the long term.