Study On Preparation And Properties Of Acrylamide-based Microgel Spheres

Poly(acrylamide-co-itaconic acid) (P(AM-co-IA)) microgel spheres with a size range of 0.5-5μm were prepared via inverse suspension polymerization, using N,N'-methylenebisacrylamide (Bis-A), potassium persulfate (KPS) as cross-linker and initiator, respectively. Sorbitan monooleate (Span-80) and polyoxyethylene-60-sorbitan monooleate (Tween-60) were chosen as co-stabilizers. Results of particle sizing analysis showed that the particle size of microgel spheres increased by increasing initiator concentration and decreased by increasing concentration of stabilizer or cross-linker. Swellability of P(AM-co-IA) microgel spheres in water and saline were calculated, which showed the maximum swelling ratio in water and saline 6859g/g and 3375g/g. P(AM-co-IA) microgel spheres showed good thermal stability through DSC and TG characterization.Mondispersed P(AM-co-IA) microgel spheres with a size range of 0.3-1μm were successfully prepared from AM and IA monomers by batch dispersion polymerization and delayed addition dispersion polymerization, respectively. The effects of monomer ratio and the concentrations of stabilizer (poly(N-vinylpyrrolidone), PVP), initiator (2,2'-azobisisobutyronitrile, AIBN) and cross-linker (Bis-A) on particle size and size distribution were systematically investigated. The particle size increased with the increase of IA content, whereas decreased with the increase of PVP-K30, AIBN and Bis-A concentration. The microgel spheres prepared from batch method showed some dissociation. However, those prepared from delayed addition method showed good swelling ratio at 96.9g/g, due to the intense and homogenous network in the microgel spheres.A series of monodispersed P(AM-co-IA) microgel spheres with a size range of 100-300nm were prepared via inverse emulsion polymerization, using Bis-A, AIBN as cross-linker and initiator, respectively. Span-80 and Tween-60 were chosen as co-emulsifers. Results of particle sizing analysis showed that the particle size of P(AM-co-IA) microgel spheres increased by increasing AM content and decreased by increasing stabilizer or cross-linker concentration. With the increase of initiator concentration, P(AM-co-IA) microgel spheres increased to a maximum size, and then decreased. Through water absorbency test, we could calculate the optimal swelling ratio at 180.8g/g. P(AM-co-IA) microgel spheres showed good thermal stability by DSC and TG characterization.Microgel spheres prepared from the above three polymerization method all showed good water absorbency capacity and some kind of strength due to polymer network, and somehow exhibited good thermal stability. If we compared water absorbency performance, those synthesized by inverse suspension polymerization had the vast water absorbency capacity, while particles from dispersion polymerization showed the worst water absorbency capacity.