Physical gelation of polystyrene-block-poly(ethylene/butylene)-block-polystyrene copolymer in paraffinic oil. Oscillatory shear and compression measurements

The thermoreversible gelation of the triblock copolymer polystyrene-block-poly(ethylene/butylene)-block-polystyrene (SEBS2) in paraffinic oil was studied. The solvent used is selective for the middle PEP block of the copolymer. The thermal behaviour as a function of copolymer concentration was investigated. The sol-gel transition temperature increases with the copolymer concentration. The mechanical properties were examined through oscillatory shear and compression measurements. The concentration dependence of the elastic storage modulus, G', was established. The relaxation rates observed were extremely high, indicating a considerable mobility in the gel during the measurement time.