Effects of Pore-Forming Agents and Polymer Composition on the Properties of Novel Poly(N,N-Dimethylaminoethyl Methacrylate Sulfate-co-N,N-dimethylacrylamide) Hydrogels

Abstract

Homopolymer of N,N-dimethylaminoethyl methacrylate sulfate (DMAEMASA) and its copolymer with N,N-dimethylacrylamide (DMAm) [P(DMAEMASA-co-DMAm)] were synthesized in the presence and absence of pore-forming agents NaHCO(3), poly(ethylene glycol) 2000 (PEG), and sucrose (SUC). The polymers were characterized by equilibrium swelling measurements (ESVs) in distilled water (20-60 degrees C) and buffer solutions (I=0.1 M, pH = 2.2-10.0, 20 degrees C), FTIR, DSC, and SEM methods. The presence of DMAm in monomer feed and the use of pore-forming agents during the polymerization enhanced the swelling of polymers. ESVs of both porous and nonporous PDMAEMASA and P(DMAEMASA-co-DMArn) gels decreased with pH, and displayed a phase transition at pH = 5. Among the pore-formers, NaHCO(3) made the highest contribution to the swelling of polymers, but poly(ethylene glycol) and sucrose slightly affected the swelling values of gels. Wile glass transition temperature (T(g)) of nonporous DMAEMASA homopolymer was determined to be 168.4 degrees C, T(g)s of nonporous copolymer with 20- and 40-mol % DMAm were found to be 154.5 and 147.8 degrees C, respectively. Pore-formers decreased the Tg of homopolymer in the order NaHCO(3) < PEG < SUC. In case of copolymers, NaHCO(3) and PEG had nearly no effect on T(g)s, but sucrose led to approximately 7 degrees C decrease in T(g)s of copolymers.