1.1 ,This test method covers the determination of styrene content, and is intended for general use on solid uncompounded styrene-butadiene copolymers, commonly referred to as SBR, prepared by the emulsion process. SBR polymers prepared in solution will require the use of different refractive index tables because the vinyl content of the butadiene differs from that in the emulsion polymers. It is applicable to polymers having less than 55 ,% bound styrene.