Full definition
Styrene-Butadiene Rubber — the largest-volume synthetic elastomer produced globally (~6 million tonnes/year), offering good abrasion resistance, adequate aging stability, and the lowest cost of any synthetic rubber. Developed during WWII as a replacement for natural rubber. Styrene content: typically 23.5% (standard SBR 1500/1502 — emulsion polymerized, most common general-purpose grade). Properties: hardness 40-90 Shore A (compounded), tensile 10-25 MPa (with carbon black reinforcement), elongation 300-600%, resilience 50-60% (lower than NR). ASTM D2000: AA/BA. Types: E-SBR (emulsion polymerized — general industrial), S-SBR (solution polymerized — lower rolling resistance for modern tire treads). Limitations: poor oil resistance, poor ozone resistance (needs antiozonant), lower tear and tensile than NR (does not strain-crystallize). Applications: tire treads and sidewalls (largest consumption), industrial rubber sheet and flooring (SBR sheet is the standard economical industrial rubber), conveyor belt covers, shoe soles, gaskets, hose covers, and carpet backing. Often blended with NR (for better tear/fatigue) or BR (for better resilience and low-temperature properties).