Testing of Compositional Distribution in Brominated Isobutylene Elastomers

Abstract A method based on high-performance liquid chromatography (HPLC) method has been developed for the characterization of the compositional distribution of brominated poly(isobutylene- co -4-methylstyrene) and poly(isobutylene- co -isoprene). The desired separations in normal-phase chromatographic mode could only be achieved by using columns packed with specifically developed 10 and 3 µm porous monodisperse poly(2,3-dihydroxypropyl methacrylate- co -ethylene dimethacrylate) beads that have a homogeneous coverage of aliphatic hydroxyl groups. Linear gradients of tetrahydrofuran in hexane and dichloromethane in heptane were used respectively as the mobile phases for the selective elution of brominated poly(isobutylene- co -4-methylstyrenes) and brominated poly(isobutylene- co -isoprenes). In-column solvo-thermal treatment of the stationary phase further improved both selectivity and retention and enabled the easy detection and detailed quantification of differences in bromine content well below 1 mol %.