Synthesis and properties of P(NIPA-co-AM) superporous hydrogel

Poly(N-isopropylacrylamide-co-acrylic amide) [P(NIPA-co-AM)] 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.