Oil absorbents based on styrene-butadiene rubber

Four oil absorbents based on styrene-butadiene (SBR)-pure SBR (PS), 4-tert-butylstyrene-SBR (PBS), EPDM-SBR network (PES), and 4-tert-butylstyrene-EPDM-SBR (PBES)-were produced from crosslinking polymerization of uncured styrene-butadiene rubber (SBR), 4-tert-butylstyrene (tBS), and ethylene-propylene-diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a prepolymer and a crosslink agent in this work, and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with ASTM method F726-81. The order of maximum oil absorbency was PBES > PBS > PES > PS. The maximum values of oil absorbency of PBES and PBS were 74.0 and 69.5 g/g, respectively. Gel fractions and swelling kinetic constants, however, had opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49.97 X 10(-2) h(-1). The gel strength parameter, S, the relaxation exponent, n, and the fractal dimension, d(f), of the crosslinked polymer at the pseudo-critical gel state were determined from oscillatory shear measurements by a dynamic rheometer. The morphologies and light resistance properties of the crosslinked polymers were observed, respectively, with a scanning electron microscope (SEM) and a color difference meter. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1818-1824, 2003.