Thermo-responsive poly(N-isopropylacrylamide-co-styrene)[P(NIPAM-co-St)] hydrogel microspheres were prepared by surfactant-free emulsion polymerization. The effects of initiator dosage, stirring rate, phase ratio and ...Thermo-responsive poly(N-isopropylacrylamide-co-styrene)[P(NIPAM-co-St)] hydrogel microspheres were prepared by surfactant-free emulsion polymerization. The effects of initiator dosage, stirring rate, phase ratio and polymerization time on particle size and monodispersity were investigated.The results showed that, with increasing initiator dosage,mean diameter increased slightly to a maximum, and then decreased drastically; meanwhile, the monodispersity of the particles became a little better at first, and then became worse significantly. With increasing stirring rate,particle diameter decreased while the monodispersity became worse. When the amount of phase rate increased, the mean diameter became larger simply, whereas the monodispersity became worse firstly and then became better again. As the polymerization proceeded, the mean diameter of the particles hardly changed, and the monodispersity became better gradually. The microspheres prepared under the optimum experimental conditions showed satisfactory particle size and monodispersity.展开更多
Inverse suspension polymerization of acrylamide was carried out in benzene continuous phase using cellulose acetate as suspension stabilizer and ammonium persulfate as initiator.An ideal recipe was recommended for the...Inverse suspension polymerization of acrylamide was carried out in benzene continuous phase using cellulose acetate as suspension stabilizer and ammonium persulfate as initiator.An ideal recipe was recommended for the preparation of monodispersed polyacrylamide particles of 150—297μm in diameter and 1.5—4.0 nm in polymer network pore size through experiments.The effects of initial monomer concentration,stabilizer concentration,initiator concentration and agitation rate on the diameter and diameter distribution of polymer particles were systematically studied.展开更多
The emulsifier free emulsion polymerization of styrene and N isopropylacrylamide(NIPAM) was successfully carried out with microwave irradiation,and the thermosensitive particles with diameters in the range 130～150?nm...The emulsifier free emulsion polymerization of styrene and N isopropylacrylamide(NIPAM) was successfully carried out with microwave irradiation,and the thermosensitive particles with diameters in the range 130～150?nm were prepared.The effect of temperature on the hydrodynamic diameter of particles was characterized by PCS,the diameter of particles was decreased as the temperature increased from 25℃ to 40℃,and the particles showed thermo reversible phase transition phenomenon at 32℃.The morphology,size and size distribution of the particles were characterized by SEM and PCS.The ordered two dimensional films were prepared by using the capillary force method on the clean glassware wafers,and the morphology of two dimensional films was studied by AFM.展开更多
基金国家自然科学基金 (No 2 0 2 0 60 19)教育部留学回国人员科研启动基金 (No [2 0 0 2 ] 2 47)资助项目~~
文摘Thermo-responsive poly(N-isopropylacrylamide-co-styrene)[P(NIPAM-co-St)] hydrogel microspheres were prepared by surfactant-free emulsion polymerization. The effects of initiator dosage, stirring rate, phase ratio and polymerization time on particle size and monodispersity were investigated.The results showed that, with increasing initiator dosage,mean diameter increased slightly to a maximum, and then decreased drastically; meanwhile, the monodispersity of the particles became a little better at first, and then became worse significantly. With increasing stirring rate,particle diameter decreased while the monodispersity became worse. When the amount of phase rate increased, the mean diameter became larger simply, whereas the monodispersity became worse firstly and then became better again. As the polymerization proceeded, the mean diameter of the particles hardly changed, and the monodispersity became better gradually. The microspheres prepared under the optimum experimental conditions showed satisfactory particle size and monodispersity.
文摘Inverse suspension polymerization of acrylamide was carried out in benzene continuous phase using cellulose acetate as suspension stabilizer and ammonium persulfate as initiator.An ideal recipe was recommended for the preparation of monodispersed polyacrylamide particles of 150—297μm in diameter and 1.5—4.0 nm in polymer network pore size through experiments.The effects of initial monomer concentration,stabilizer concentration,initiator concentration and agitation rate on the diameter and diameter distribution of polymer particles were systematically studied.
文摘The emulsifier free emulsion polymerization of styrene and N isopropylacrylamide(NIPAM) was successfully carried out with microwave irradiation,and the thermosensitive particles with diameters in the range 130～150?nm were prepared.The effect of temperature on the hydrodynamic diameter of particles was characterized by PCS,the diameter of particles was decreased as the temperature increased from 25℃ to 40℃,and the particles showed thermo reversible phase transition phenomenon at 32℃.The morphology,size and size distribution of the particles were characterized by SEM and PCS.The ordered two dimensional films were prepared by using the capillary force method on the clean glassware wafers,and the morphology of two dimensional films was studied by AFM.
