Cationic cyclization of styrene–butadiene rubber

Controlled cyclization of styrene–butadiene rubber (SBR) was achieved with the aid of cationic catalyst system based on diethylaluminium chloride (AlEt2Cl) and benzyl chloride (C6H5CH2Cl) and by working in xylene solution at high temperature (T>100°C). The main parameters of the cyclization process were investigated. Elastomers with low intrinsic viscosity, ready solubility, free gel were obtained. The products were characterized with IR 1 H-NMR, DSC, GPC. The polycyclic structure was determined.