POROUS STRUCTURE AND SWELLING PROPERTIES OF STYRENE-DIVINYLBENZENE COPOLYMERS FOR SIZE-EXCLUSION CHROMATOGRAPHY

Small spherical particles of styrene-divinylbenzene copolymers have be en synthesized by modified suspension polymerization. The effects of d ivinylbenzene (DVB) contents, dilution degree of the monomers and dilu ent composition on the porous structure and swelling properties of the copolymers were investigated. Toluene uptakes of macroporous copolyme rs were considered as a result of three contributions: filling of the fixed pores, expansion of the fixed or collapsed pores, and nuclei swe lling and heptane uptakes as a result of the two first contributions. The increase of DVB content in the copolymers synthesized in presence of a solvating diluent (toluene) provoked a decrease on the nuclei swe lling. The increase of dilution degree with solvating diluents changed the toluene and heptane uptakes, and when the diluent-copolymer affin ity was reduced, the fixed pore volume increased. (C) 1997 John Wiley & Sons, Inc.