P(St-GMA)/Fe3O4磁性聚合物微球的制备及表征

采用沉淀法制备了Fe3O4纳米粒子, 以苯乙烯(St)、甲基丙烯酸缩水甘油酯(GMA)为聚合单体, 使用分散聚合法制备了P(St-GMA)/Fe3O4磁性聚合物微球. 分析了Fe3O4粒子的形貌和结构. 研究了制备条件对磁性聚合物微球磁含量的影响. 采用FTIR, XRD, TG及TEM等手段对磁性聚合物微球的微观结构及形貌、磁含量等进行了分析表征. 研究结果表明, 制备的磁性聚合物微球粒径均一, 磁含量高达74%.     

1,1-二苯基乙烯存在下无皂乳液聚合制备磁性复合微球

报道了一种制备磁性复合微球的方法——DPE法.在自由基控制剂1,1-二苯基乙烯(DPE)存在条件下,甲基丙烯酸甲酯(MMA)与丙烯酸(AA)发生无皂乳液聚合,制备能与Fe3O4粒子相螯合的活性短链共聚物,加入Fe3O4粒子把短链共聚物引到其表面,引发其它单体继续在Fe3O4粒子表面聚合,制备磁性复合微球.研究了AA、DPE、引发剂及Fe3O4粒子加入量等对制备磁性复合微球的影响.并在此基础上,对优化后工艺制备的磁性复合微球进行了TEM、TGA及磁响应性表征.结果表明,利用该新的方法制备出了磁含量为20%、比饱和磁化强度为32.2emu/g、平均粒径为265nm且表面不含任何杂质的磁性复合微球.     

控制自由基聚合制备Fe_3O_4/SiO_2/P(AA-MMA-St)磁性复合微球

用原硅酸乙酯对Fe3O4纳米粒子进行表面改性得到Fe3O4/SiO2磁流体.在Fe3O4/SiO2磁流体存在下,以1,1-二苯基乙烯(DPE)为自由基聚合控制剂,利用乳液聚合法制备了Fe3O4/SiO2/P(AA-MMA-St)核-壳磁性复合微球.用红外光谱(FTIR)、振动样品磁强计(VSM)、透射电镜(TEM)、X光电子能谱(XPS)、热重分析(TGA)、示差扫描量热仪(DSC)对所制备的磁流体、磁性高分子复合微球的结构、形态、性能进行了表征.研究发现,原硅酸乙酯水解后能在Fe3O4表面形成硅膜保护层从而避免Fe3O4的酸蚀,使Fe3O4/SiO2/P(AA-MMA-St)复合微球的比饱和磁化强度比同样条件下制备的Fe3O4/P(AA-MMA-St)微球提高了28%;DPE能有效控制自由基在Fe3O4/SiO2磁流体表面均匀地引发单体聚合,得到平均粒径为422 nm,无机粒子含量为40%,比饱和磁化强度为34.850 emu/g,表面羧基含量为0.176 mmol/g的磁性复合微球.     

免疫磁性纳米微球的制备与表征

成功制备了Fe3O4磁性纳米颗粒及二甲基丙烯酸乙二醇酯-甲基丙烯酸(EGDMA-MAA)共聚物包覆的Fe3O4磁性复合微球。将吲哚美辛抗体固定在复合微球表面,形成了Fe3O4(核)/聚合物-抗体(壳)的复合免疫磁性颗粒。XRD结果表明,制备的Fe3O4的晶型为反立方尖晶石型且纯度较高;TEM表征表明Fe3O4粒径较为均匀,平均粒径为12nm;磁性复合微球的平均直径为460nm。制备的Fe3O4磁性纳米颗粒和磁性复合微球有较强的磁响应强度,其饱和磁化率分别为49.16和8.38emu/g,能够满足磁性分离的要求。FT IR验证了磁性复合微球中羧基特征峰的存在,表明羧基成功连接在磁性微球上面。通过碳二亚胺/N-羟基琥珀酰亚胺(EDC/NHS)活化法将微球表面羧基活化并成功与抗吲哚美辛抗体交联。     

Fe_3O_4/P(NaUA-St-BA)核-壳纳米磁性复合粒子的合成与表征

以表面包敷有反应型的表面活性剂NaUA(十一烯酸钠)的Fe3O4磁性胶体粒子为种子,运用无皂乳液聚合方法原位制备出Fe3O4P(NaUAStBA)核壳纳米磁性复合粒子.Fe3O4磁性胶体粒子的粒径为10nm左右.IR和TG结果分析表明,苯乙烯、丙烯酸酯和NaUA在Fe3O4粒子的表面发生了聚合反应,形成P(NaUAStBA);TEM和激光粒度分析仪测试结果显示,Fe3O4P(NaUAStBA)复合粒子具有核壳结构而且粒子分布均匀、平均粒径60nm;TG测试的结果表明,NaUA在Fe3O4粒子的包覆率为13.83%,P(NaUAStBA)共聚物的包覆率71.85%;振动样品磁强仪(VSM)测试的磁滞回线则表明由无皂乳液聚合得到的Fe3O4P(NaUAStBA)复合粒子具有超顺磁性,可避免磁性微球在磁场中的团聚.另外,合成的磁性胶乳可稳定存放数月.     

Fe3O4/P(NaUA-St-BA)核-壳纳米磁性复合粒子的合成与表征

以表面包敷有反应型的表面活性剂NaUA（十一烯酸钠）的Fe3O4磁性胶体粒子为种子,运用无皂乳液聚合方法原位制备出Fe3O4／P（NaUA-St-BA）核-壳纳米磁性复合粒子,Fe3O4磁性胶体粒子的粒径为10nm左右,IR和TG结果分析表明,苯乙烯、丙烯酸酯和NaUA在Fe3O4粒子的表面发生了聚合反应,形成P（NaUA-St-BA）;TEM和激光粒度分析仪测试结果显示,Fe3O4／P（NaUA-St-BA）复合粒子具有核-壳结构而且粒子分布均匀、平均粒径60nm;TG测试的结果表明,NaUA在Fe3O4粒子的包覆率为13．83％,P（NaUA-St-BA）共聚物的包覆率71．85％;振动样品磁强仪（VSM）测试的磁滞回线则表明由无皂乳液聚合得到的Fe3O4／P（NaUA-St-BA）复合粒子具有超顺磁性,可避免磁性微球在磁场中的团聚。另外,合成的磁性胶乳可稳定存放数月。     

表面含羧基的交联磁性高分子复合微球的合成

首先用化学共沉淀法制备了Fe3O4纳米微粒,并对其表面进行改性。然后在分散介质水中,以二乙烯基苯(DVB)为交联剂,采用改进的乳液聚合法,制备了磁性Fe3O4为核、苯乙烯和丙烯酸的共聚物为壳的交联复合微球,并利用FT-IR、TEM、XRD和XPS等对其进行表征。结果表明:该复合微球的粒度分布均匀、表面含有一定羧基,为单分散性、表面功能化的交联磁性高分子纳米复合微球。     

ZnO@P(AA/MMA/GMA)@Fe3O4复合微球：制备及光催化性能

采用导向沉淀法在胺化的P(AA/MMA/GMA)@Fe3O4(MCM,其中AA为丙烯酸,MMA为甲基丙烯酸甲酯,GMA为甲基丙烯酸缩水甘油酯)微球表面负载ZnO粒子制备得到了ZnO@P(AA/MMA/GMA)@Fe3O4(ZPM)三层结构磁性复合微球。通过XRD、SEM、粒度分析、TGA及VSM等手段对ZPM微球进行表征,结果表明:ZPM微球平均粒径为1.38μm,ZnO负载量为13.02%,比饱和磁化强度为8.64 emu.g-1。同时研究了ZPM微球的光催化性能,以罗丹明B(RhB)为被降解物,微球对RhB的吸附效率为50.07%,催化降解效率可达93.40%。     

高Fe3O4含量微米尺寸磁性复合微球的合成及其在化学发光免疫检测中应用初探

采用种子乳液聚合方法制得了微米尺度的高磁性物质含量的磁性复合微球.聚合体系中,以0.7～0.8 μm的Fe3O4磁性聚集体细乳液作为种子,将苯乙烯,二乙烯基苯作为聚合单体加入到磁性聚集体细乳液中,对Fe3O4磁性聚集体进行溶胀后进行聚合.研究了聚合过程中,溶胀时间对复合微球形貌和磁性物质含量的影响,获得系列形貌微球.通过透射电镜(TEM)、热重分析(TGA)、红外分析(FTIR)、振动样品磁强计(VSM)等表征手段对所制备的磁性聚合物微球进行分析表征.结果显示,所得到的磁性聚合物微球粒度为0.7～1 μm,尺寸分布较均一,具有超顺磁性,磁性物质含量为29 wt%～57 wt%.然后又通过丙烯酸和苯乙烯共聚对微球表面羧基功能化后,得到了表面羧基密度为0.92 mmol/g的微球,再将所制备的微球与生物分子偶联后(以hCG作为模式待检分子),在化学发光免疫检测上进行了初步的应用,取得到了较好的应用结果.     

高Fe_3O_4含量单分散P(St/AA)复合微球的合成与表征

在表面由十一烯酸和油酸共同修饰的Fe3O4磁流体存在下,以苯乙烯(St)和丙烯酸(AA)为共聚单体,用细乳液聚合法,制备了单分散,高Fe3O4含量,且表面带有羧基的超顺磁性高分子复合微球.采用透射电镜(TEM),热重分析(TGA),物性测量系统(PPMS),Zeta电位以及红外光谱等手段对磁性复合微球的各项性能进行表征.结果表明,Fe3O4粒子的表面改性是影响复合微球Fe3O4含量及形貌的关键因素.在优化的实验条件下,可以制得Fe3O4含量高达77wt%,平均粒径为137·9nm,表面羧基密度0·0894mmol/g,比饱和磁化强度为44·7emu/g的单分散超顺磁性高分子复合微球.     

Monodispers and Multifunctional Magnetic Composite Core Shell Microspheres for Demulsification Applications

Iron oxide@Poly(Glycidylmethacrylate‐methyl methacrylate‐divinyl benzene) magnetic composite core shell microspheres Fe₃O₄@P(GMA‐MMA‐DVB) with epoxy group on the surface was designed and synthesized by solvothermal process followed by distillation polymerization. The surface epoxy group was modified with amino group of ethylene diamine (EDA) to prepare Fe₃O₄@P(GMA‐MMA‐DVB)/NH₂ microspheres, and then effects of modification on the structure, interfacial behavior and hence demulsification of the amino modified epoxy coating were examined. The prepared magnetic microspheres were characterized using a laser particle size analyzer, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and thermogravimetric analysis. Fourier transform infrared spectrometer analysis indicates the presence of epoxy group, amino group and Fe₃O₄ in the final Fe₃O₄@P(GMA‐MMA‐DVB) and Fe₃O₄@P(GMA‐MMA‐DVB)/NH₂ magnetic core shell microspheres. Our experimental results show that Fe₃O₄@P(GMA‐MMA‐DVB)/NH₂ magnetic core shell microspheres exhibit good interfacial and demulsification properties and able to remove emulsified water from stable emulsion. The resulting microspheres showed excellent magnetic properties and further these can be recycled and reused by magnetic separation.     

Toward designer magnetite/polystyrene colloidal composite microspheres with controllable nanostructures and desirable surface functionalities

An effective method was developed for synthesizing magnetite/polymer colloidal composite microspheres with controllable variations in size and shape of the nanostructures and desirable interfacial chemical functionalities, using surfactant-free seeded emulsion polymerization with magnetite (Fe(3)O(4)) colloidal nanocrystal clusters (CNCs) as the seed, styrene (St) as the monomer, and potassium persulfate (KPS) as the initiator. The sub-micrometer-sized citrate-acid-stabilized Fe(3)O(4) CNCs were first obtained via ethylene glycol (EG)-mediated solvothermal synthesis, followed by 3-(trimethoxysilyl)propyl methacrylate (MPS) modification to immobilize the active vinyl groups onto the surfaces, and then the hydrophobic St monomers were polymerized at the interfaces to form the polymer shells by seeded emulsion radical polymerization. The morphology of the composite microspheres could be controlled from raspberry- and flower-like shapes, to eccentric structures by simply adjusting the feeding weight ratio of the seed to the monomer (Fe(3)O(4)/St) and varying the amount of cross-linker divinyl benzene (DVB). The morphological transition was rationalized by considering the viscosity of monomer-swollen polymer matrix and interfacial tension between the seeds and polymer matrix. Functional groups, such as carboxyl, hydroxyl, and epoxy, can be facilely introduced onto the composite microspheres through copolymerization of St with other functional monomers. The resultant microspheres displayed a high saturation magnetization (46 emu/g), well-defined core-shell nanostructures, and surface chemical functionalities, as well as a sustained colloidal stability, promising for further biomedical applications.     

Fabrication and functionalization of dendritic poly(amidoamine)-immobilized magnetic polymer composite microspheres

The synthesis of functionalized magnetic polymer microspheres was described by a process involving (1) preparation of the monodisperse magnetic seeds according to a two-step procedure including the preparation of bilayer-oleic acid-coated Fe3O4 nanoparticles followed by soap-free emulsion polymerization with methyl methacrylate (MMA) and divinyl benzene (a cross-linking agent, DVB); (2) seeded emulsion polymerization proceeding under the continuous addition of glycidyl methacrylate (GMA) monomers in the presence of the magnetic PMMA seeds; and (3) chemical modification of the PGMA shells with ethylenediamine (EDA) to yield amino groups. As such, the magnetic poly(MMA-DVB-GMA) microspheres were prepared possessing monodispersity, uniform magnetic properties, and abundant surface amino groups. Then, the dendritic poly(amidoamine) (PAMAM) shells were coated on the magnetic particles on the basis of the Michael addition of methyl acrylate and the amidation of the resulting ester with a large excess of EDA, which could achieve generational growth under such uniform stepwise reactions. For improving the luminescence properties of the composite particles, fluorescein isothiocyanate, which is a popular organic dye, was reacted with the terminal -NH2 groups from the dendritic PAMAM shells, resulting in the formation of multifunctional microspheres with excellent photoluminescence, superparamagnetic, and pH-sensitive properties. In this case, it can be expected that an extension of the functionalization of these microspheres is to immobilize other target molecules onto the PAMAM shells to introduce other desired functions for potential chemical and biological applications.     

Sulfonic acid-functionalized core-shell Fe_3O_4@carbon microspheres as magnetically recyclable solid acid catalysts

Green and recyclable solid acid catalysts are in urgent demand as a substitute for conventional liquid mineral acids.In this work,a series of novel sulfonic acid-functionalized core-shell Fe_3 O_4@carbon microspheres(Fe_3 O_4@C-SO_3 H) have been designed and synthesized as an efficient and recyclable heterogeneous acid catalyst.For the synthesis,core-shell Fe_3 O_4@RF(resorcinol-formaldehyde) microspheres with tunable shell thickness were achieved by interfacial polymerization on magnetic Fe_3 O_4 microspheres.After high-temperature carbonization,the microspheres were eventually treated by surface sulfonation,re sulting in Fe_3 O_4@C-x-SO_3 H(x stands for carbonization temperature) microspheres with abundant surface SO_3 H groups.The obtained microspheres possess uniform core-shell structure,partially-graphitized carbon skeletons,superparamagnetic property,high magnetization saturation value of 10.6 emu/g,and rich SO_3 H groups.The surface acid amounts can be adju sted in the range of 0.59-1.04 mmol/g via sulfonation treatment of carbon shells with different graphitization degrees.The magnetic Fe_3 O_4@C-x-SO_3 H microspheres were utilized as a solid acid catalyst for the acetalization reaction between benzaldehyde and ethylene glycol,demonstrating high selectivity(97%) to benzaldehyde ethylene glycol acetal.More importantly,by applying an external magnetic field,the catalysts can be easily separated from the heterogeneous reaction solutions,which later show well preserved catalytic activity even after 9 cycles,revealing good recyclability and high stability.     

Fe3 O4 /P(NVP-MAA)核壳复合微球的制备与表征

以N-乙烯基吡咯烷酮（NVP）和甲基丙烯酸（MAA）为原料,过硫酸钾为引发剂,采用乳液聚合的方法共聚包埋自制的磁流体Fe3O4,制得了Fe3O4／P（NVP—MAA）核壳复合微球。以粒径,羧基含量,Fe3O4含量为指标,采用L9（3^4）正交表,探讨了反应温度、单体总用量、单体配比和引发剂用量对反应的影响。通过多指标极差分析,确定了制备复合微球的最佳条件。并用IR,TG,SEM及XRD对其结构进行了表征。     

Mono- or narrow disperse poly(methacrylate-co-divinylbenzene) microspheres by precipitation polymerization

Precipitation copolymerizations of five mono-vinyl methacrylic monomers including methyl methacrylate (MMA), butyl methacrylate (BMA), dodecyl methacrylate (DMA), glycidyl methacrylate (GMA), and hydroxyethyl methacrylate (HEMA) with divinylbenzene (DVB), in a wide range of comonomer composition, were carried out in acetonitrile to form mono- or narrow disperse crosslinked copolymer microspheres. In addition, two divinyl methacrylic monomers, ethylene glycol dimethacrylate (EGDMA) and triethylene glycol dimethacrylate (TEGDMA), were also copolymerized with DVB, and optionally a third comonomer (GMA or HEMA), to yield similar microspheres in acetonitrile. The possibility of creating porosity was explored for some of the copolymer particles. All these microspheres have clean surfaces due to the absence of any added steric or ionic stabilizer, and they are in the size of the micrometer range, varying from 1 to 7 µm, depending on the type and content of the methacrylic comonomer. Particle size distribution, surface morphology, internal texture, and porosity properties of these particles were studied by a Coulter Multisizer, a scanning electron microscope, a transmission electron microscope, and an Autosorb-1. The effects of comonomers on microsphere formation and morphology are described. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2899–2907, 1999