SWELLING EQUILIBRIA FOR HETEROGENEOUS POLYACRYLAMIDE GELS

摘要

To correlate swelling equilibria for heterogeneous polyacrylamide gels in water to the monomer concentration at preparation, it is necessary to modify the classic Flory-Rehner theory. The necessary modification concerns the relation which links the number of segments between junction points to the monomer concentration at preparation; that relation is here adjusted empirically. Modified theory is compared to experimental swelling equilibria for polyacrylamide gels synthesized in water by free-radical copolymerization of acrylamide (AAm) and N,N'-methylenebis(acrylamide) (BIS) at various monomer concentrations. Synthesis conditions studied are (1) different AAm-to-BIS ratios with fixed total monomer concentrations, (2) different total monomer concentrations with fixed AAm-to-BIS ratios, and (3) different AAm-to-BIS ratios with a fixed number of BIS molecules. The modified theory and experiment show good agreement. (C) 1996 John Wiley & Sons, Inc. [References: 27]