PREPARATION OF CROSSLINKED MEMBRANES WITH CONTROLLED PORE-SIZE DISTRIBUTION

A technique has been developed to prepare crosslinked, porous/asymmetric membranes from poly(styrene-co-divinylbenzene). Mixtures of styrene monomer, divinylbenzene, benzoin (a photo-initiator), and some dead polystyrene are dissolved in a cosolvent and cast on a flat, transparent substrate. The coating is then irradiated with a UV lamp and subsequently phase separated by exposure to a nonsolvent bath. Pores and generated by phase separation induced by nonsolvent ingression. Crosslinking is achieved via the photo-initiated incorporation of divinylbenzene with styrene, while the membrane morphology evolves. A mechanism for the formation of crosslinked membranes prepared by this technique is proposed.