Synthesis and properties of P superporous hydrogel

Poly(N-isopropylacrylamide-co-acrylic amide) superporous hydrogels were prepared by dispersion polymerization in foam state using N-isopropylacrylamide (NIPA) and acrylic amide (AM) as monomers, ammonium persulfate (APS) as initiator, N, N’-Methylene-bis-acrylamide (BIS) as crosslink agent . Its swelling ratio and deswelling ratio were measured when the molar content of AM, the dosages of initiator or crosslink agent or HCI or NaHCO₃ were changed. The structure of SPH was characterized by DSC, FTIR and SEM. The results show that lower critical solution temperature(LCST) of P(NIPA-co-AM) gels is improved with the increasing molar content of AM. The hydrogel prepared at condition of x(AM)=20%, ρ(APS)=20g/L, ρ(BIS)=3.5g/L, c(HCI)= 0. 55mol/L, ρ(NaHCO₃)= 5.0×10²g/L, is more superporous which has higher swelling ratio and deswelling ratio, and good temperature sensitive properties, which makes it possible to load and release with macromolecular drugs.