Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with ol...Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2’-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of-1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu.g-1. There was abundance of epoxy groups with density of 0.028 mmol·g^-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology.展开更多
Monosize, 1.6 μm, magnetic beads of poly（glycidyl methacrylate） [M-poly（GMA）], were prepared by dispersion polymerization in the presence of Fe3O4 nano-powder. Monosize M-poly（GMA） beads were characterized by s...Monosize, 1.6 μm, magnetic beads of poly（glycidyl methacrylate） [M-poly（GMA）], were prepared by dispersion polymerization in the presence of Fe3O4 nano-powder. Monosize M-poly（GMA） beads were characterized by swelling tests, density measurements, electron spin resonance （ESR）, vibrating sample magnetometer （VSM） and scanning electron microscopy （SEM）. The characteristic functional groups of M-poly（GMA） beads were analyzed by Fourier transform infrared spectrometer （FTIR）. The M-poly（GMA） beads are highly uniform in size and have a spherical shape and non-porous structure. Polydispersity index （PDI） of M-poly（GMA） beads was calculated to be around 1.008. The hydrated density of the M-poly（GMA） beads measured at 25 ℃ was 1.14 g/cm^3. The content of oxirane groups on the surface of the M-poly（GMA） sample was found to be 3.46 mmol/g by using perchloric acid titration. The specific surface area of the M-poly（GMA） beads was determined to be 3.2 m^2/g. The equilibrium swelling ratio was 52%. The volume fraction of magnetite nanopowder in the M-poly（GMA） beads was found to be 4.5%. The g factor, that can be considered as a quantity characteristic of the molecules in which the unpaired electrons are located, was found to be 2.28 for M-poly（GMA）. The external magnetic field at resonance was calculated to be 2055 Gs which was found sufficient to excite all of the dipole moments present in 1.0 g of M-poly（GMA） sample.展开更多
基金Supported by 863 Hi-Technology Research and Development Program of China (No. G2002AA302211)the National Natural Science Foundation of China (No. 20206032).
文摘Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2’-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of-1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu.g-1. There was abundance of epoxy groups with density of 0.028 mmol·g^-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology.
文摘Monosize, 1.6 μm, magnetic beads of poly（glycidyl methacrylate） [M-poly（GMA）], were prepared by dispersion polymerization in the presence of Fe3O4 nano-powder. Monosize M-poly（GMA） beads were characterized by swelling tests, density measurements, electron spin resonance （ESR）, vibrating sample magnetometer （VSM） and scanning electron microscopy （SEM）. The characteristic functional groups of M-poly（GMA） beads were analyzed by Fourier transform infrared spectrometer （FTIR）. The M-poly（GMA） beads are highly uniform in size and have a spherical shape and non-porous structure. Polydispersity index （PDI） of M-poly（GMA） beads was calculated to be around 1.008. The hydrated density of the M-poly（GMA） beads measured at 25 ℃ was 1.14 g/cm^3. The content of oxirane groups on the surface of the M-poly（GMA） sample was found to be 3.46 mmol/g by using perchloric acid titration. The specific surface area of the M-poly（GMA） beads was determined to be 3.2 m^2/g. The equilibrium swelling ratio was 52%. The volume fraction of magnetite nanopowder in the M-poly（GMA） beads was found to be 4.5%. The g factor, that can be considered as a quantity characteristic of the molecules in which the unpaired electrons are located, was found to be 2.28 for M-poly（GMA）. The external magnetic field at resonance was calculated to be 2055 Gs which was found sufficient to excite all of the dipole moments present in 1.0 g of M-poly（GMA） sample.
