SYNTHESIS AND CHARACTERIZATION OF THERMOSENSITIVE POLYMERIC BEADS

Thermo‐sensitive polymeric beads were synthesized by inverse suspension polymerization of aqueous monomer solution containing N‐acryloylpyrrolidine (APR) and N,N′‐methylenebisacryl‐amide (MBA : crosslinking agent). The polymerization conditions such as dispersion medium, dispersing agent, monomer, and initiator concentration were investigated. Fine spherical gels with diameter of 50–500μm were obtained in high yield. The swelling volume of these gels in water continually decreased by raising atmospheric temperature and vice versa. The degree of swelling increased for the gels synthesized with lower degree of crosslinking or with lower monomer concentration at polymerization. The degree of swelling was high in water and alcohols, but the gels swelled even in nonpolar organic solvents, although the degree of swelling was low. The pore radius distribution of the gels was determined by aqueous size exclusion chromatographic method to investigate relations between pore characteristics of the gels and polymerization conditions. Monomer concentration had large effect on pore size, porosity, and pore volume of the gels. On the other hand, degree of crosslinking had little effect on these pore characteristics. Copyright © 1990 John Wiley & Sons, Inc.