中空介孔二氧化硅微球的制备及研究进展

中空介孔二氧化硅微球具有较大的中空空腔、可控外层介孔结构、大比表面积、良好的生物相容性等特性,因而被广泛应用于药物储存与释放、纳米反应器、催化、吸附等领域。对中空介孔二氧化硅微球的制备方法进行介绍,综述和评价了模板法、选择性刻蚀法、喷雾干燥法等三类制备方法的研究进展及其优缺点,并对其应用前景进行了展望。     

Ni/PS核壳结构纳米复合微球的制备及磁性能

采用乳液聚合法制备了纳米级聚苯乙烯微球,利用化学沉积法在微球表面镀镍,制备出了具有磁性的金属/高分子(Ni/PS)纳米复合微球。利用透射电子显微镜(TEM)、X射线衍射仪(XRD)和能量色散谱仪(EDS)分别对镀镍前后纳米微球的形貌结构、相组成、化学成分进行表征分析,用振动样品磁强计(VSM)测试了不同制备工艺条件下复合微球的磁学性能。结果表明,活化工艺、还原剂浓度、镀液pH值和温度对镀后复合微球的磁性能有显著影响。根据磁性能结果,优化工艺参数,制备了具有规则球形、单分散性好、粒径约为100nm、镀层完整、均匀的磁性Ni/PS核壳结构纳米复合微球,并获得最大的饱和磁化强度Ms=8.8764emu/g。     

磁性Fe_3O_4/PMAA高分子复合微球的制备

在以共沉淀法制备的磁性Fe3O4纳米微粒的存在下,以甲基丙烯酸(MAA)为单体,采用反相悬浮聚合法制得了一种新型的磁性Fe3O4/PMAA高分子复合微球。考察了超声波预处理,磁流体用量以及聚合反应时搅拌速度等因素对复合微球成球性的影响。利用扫描电子显微镜(SEM),X-衍射仪(XRD),能谱仪(EDS),傅里叶变换红外光谱仪(FTIR)等手段对磁性复合微球的表面形貌及组成进行了分析。实验表明,复合微球呈现球状结构,表面负载Fe3O4纳米微粒。由于此复合微球由于磁响应性具有易于分离的优点,而且由于复合微球上存在大量羧基功能基团可进行后续修饰的特点,因此,这类材料有望在构筑纳米反应器,处理印染废水等方面具有广阔的应用前景。     

二氧化硅/壳聚糖复合微球的制备及性能

通过溶胶-凝胶法制备出3种不同粒径的SiO₂微球,利用扫描电镜分析了微球的粒径分布情况,SiO₂微球粒径分别在140nm、208nm、336nm左右,在一定范围内,硅球的粒径随正硅酸四乙酯(TEOS)/氨水的添加量增加而增大。选取粒径在336nm左右的SiO₂微球,使用硅烷偶联剂3-(2,3-环氧丙氧基)丙基三甲氧基硅烷(GPTMS)将壳聚糖(CS)接枝在SiO₂微球上,得到SiO₂@CS复合微球。通过红外光谱分析、X射线衍射等对微球进行了表征。接枝CS后对SiO₂微球的结晶特性没有影响,微球仍为无定形晶体。元素分析结果表明CS的接枝量为1.03%。使用振荡法进行抗菌测试,SiO₂@CS复合微球对金黄色葡萄球菌(S.aureus)和大肠杆菌(E.coil)的抑菌率分别为85.52%和47.14%,表明复合微球有一定的抗菌效果。     

磁性药物微球制备的研究进展

在总结近年来国内外有关磁性药物微球研究成果的基础上,对磁性药物微球的几种制备方法,即直接包埋法、乳液聚合法和沉淀法的基本原理、工艺过程及特点进行了综述.     

微米二氧化硅微球的制备研究进展

以聚合诱导胶体凝聚法、种子生长法、模板法和反相乳液法等制备方法为主线,综述制备微米二氧化硅微球的最新研究进展,同时以所得微球的性能为考察重点,对各种方法进行评价与展望;提出通过硅酸钠等低成本硅原料取代硅酸酯制备高性能硅微球是未来研究重点;改变种子生长法中溶剂的种类、制备粒径更大的单分散微球并进行理论探究成为种子生长法的研究方向;采用模板法对聚合诱导胶体凝聚法制备的微球孔结构进行重组完善,得到纯度较高、机械强度和比表面积较大的微米有序介孔二氧化硅微球,进而用于高性能色谱柱的制备以及生物催化等领域,发展前景可观。     

磁性壳聚糖复合微球的制备和性能研究

本文采用乳化交联法制备了可附载放射性核素的磁靶向药物载体-磁性壳聚糖复合微球.考察了壳聚糖浓度、Fe3O4/壳聚糖质量比及搅拌速度等因素对磁性壳聚糖微球粒径、粒径分布以及形貌等对复合过程的影响,确定了制备高磁响应性的磁性壳聚糖的最佳条件,并借助不同手段对磁性壳聚糖的粒径、粒径分布、形貌及磁性能进行了初步表征.     

磁性高分子复合微球的研究进展

综合介绍了磁性复合微球的研究进展及目前常用的制备磁性复合微球的方法,总结了各种制备方法的优缺点和适用范围,并着重介绍了单体聚合法,最后展望了磁性复合微球的发展趋势.     

羧基化Fe3O4磁性纳米微球的制备及表征

采用化学共沉淀法制备纳米Fe3O4,油酸包覆,高锰酸钾氧化,修饰得到羧基功能化的亲水性磁性纳米复合粒子。通过XRD、TEM、傅里叶红外光谱仪等方法对纳米复合粒子的形态、结构及磁性能进行了研究。结果显示:修饰前后的纳米粒子粒径基本无变化,粒径20nm左右。纳米复合粒子的磁性能表现出超顺磁性,矫顽力减小为0,羧基化磁性纳米粒子可在pH=7.4的磷酸缓冲液中形成稳定分散的磁流体。     

多孔磁性复合微球的制备及其功能化研究进展

与常规磁性微球相比,多孔磁性复合微球具有比表面积大、密度小等特性,因此得到了人们的普遍关注。近几年来,多孔磁性复合微球的制备技术得到了很大发展。目前,基本实现了比表面积可控、孔径和表面化学性质可调。本文详细介绍了多孔磁性复合微球的制备方法,总结了成孔机理和影响孔结构的因素,并对磁性微球表面功能化的方法作了相关概述。     

沸石基纳米磁性材料MeFe2O4制备及表征

采用水热分散法,通过分步化学反应,简便有效地制备了沸石基纳米磁性材料,并用XRD、IR和振动样品磁强计(VSM)对所得样品进行了相关测试。测试结果表明,体相MeFe2O4的磁学参数:矫顽力Hc、饱和磁化强度Ms和剩余磁化强度Mr均有较大幅度的降低。即由体相强磁性材料变为纳米非晶软磁材料,这是纳米粒子的小尺寸效应和量子尺寸效应所致,并且XRD、IR和磁滞回线表征结果也佐证此结论。     

Fe3O4/聚苯乙烯中空微球磁性复合微粒的制备及其磁流变性能的研究

用共沉淀法在聚苯乙烯（PS）中空微球表面包覆Fe3O4，制备了Fe3O4/Ps中空微球磁性复合微粒，当磁性包覆层的厚度为30～50nm时，复合微粒的室温表现密度为1．5g/cm^3，为传统磁流变液（MRF）中所用铁粉等软磁性颗粒密度（约7．9g/cm^3）的1/5，更为接近MRF中载液的密度。复合颗粒的磁滞回线比较狭长，呈软磁性，其磁性能和Fe3O4纳米颗粒相差不大。与Fe3O4颗粒相比，Fe3O4/PS中空磁性复合微粒在水载液中的沉降稳定性大大提高，复合微粒含量越高，其沉降稳定性越好。在磁性微粒含量相同的条件下，基于Fe3O4/PS中空磁性复合微粒的MRF的磁流变性能明显优于基于Fe3O4纳米微粒的MRF。     

Fe_3O_4/木材复合材料的制备及磁性

以FeCl3和FeCl2混合液为浸渍溶液,以普通云南杉木为基体,在常温条件下,采用原位化学合成法制备出Fe3O4/木材复合材料。用X射线衍射仪、红外光谱仪及扫描电镜对复合材料的结构进行了表征,用振动样品磁强计研究了材料的磁性能。结果表明,木材中生成Fe3O4晶粒的平均粒径为14nm,但有一定团聚,木材空隙中的部分铁氧体增大到0.5～2.5μm;合成的Fe3O4与木材间有较强的相互作用,影响了复合材料的磁性能;浸渍溶液浓度对材料的磁性能具有一定影响,当浸渍溶液中Fe离子总浓度为1.2mol/L时材料磁性最强,浸渍溶液浓度过高或过低都会引起材料磁性能的降低;木材的纤维结构对材料磁性能也有一定影响,当外加磁场方向平行于材料纤维方向时,材料的剩余磁化强度要大于磁场方向垂直纤维方向时材料的剩余磁化强度。     

Preparation and characterization of Y2O3 hollow spheres

Y₂O₃ hollow spheres are prepared by coating the anionic poly (styrene-methyl acrylic acid) (PSA-A) latex with an amorphous yttrium layer and subsequent calcining at elevated temperatures in air. The aging temperature, aging time, the concentrations of Y(III) and urea are systematically varied to establish the optimum conditions for the formation of the coating shell. Zeta potential measurement, transmission electron microscopy, scanning electron microscopy, X-ray diffraction and infrared measurements are used to characterize the PSA-A latex, core-shell spheres and Y₂O₃ hollow spheres. A mechanism for the formation of the PSA-A/yttrium compounds core-shell spheres is suggested. The key factor to prepare smooth-coated spheres is obtained.     

Sol-gel synthesis, microstructure and adsorption properties of hollow silica spheres

Spherical colloidal particles with a hollow interior and a mesoporous shell are particularly useful for drug delivery and release because such spheres combine the unique properties of hollow interior (for storing the drug) with mesoporous shell (for controlled release). Hollow silica spheres (HSS) with a mesoporous shell were prepared via a sol-gel process in the presence of dual templates polystyrene spheres and cetyltrimethylammonium bromide for creating the hollow core and mesopore shell. The effect of the ratio of silica precursor over polystyrene spheres on particle morphology and pore structure of the HSS was investigated. The adsorption kinetics of methyl blue on the HSS was evaluated and correlated with the mesoporous shell structure.     

CuFe2O4/海泡石磁性吸附剂的制备及性能

以硫酸铜、氯化铁为主要原料,采用化学共沉淀法制备CuFe2O4纳米磁性微粒,然后将其与海泡石复合制得CuFe2O4载量不同(质量分数,下同)的磁性海泡石.分别用X射线衍射(XRD)、透射电子显微镜(TEM)、振动样品磁强计(VSM)对样品的物相、形貌、磁学性能进行了表征.结果表明,合成的CuFe2O4结晶度高,晶粒度约...     

Electrical and magnetic properties of Ni0.8Zn0.2Fe2O4/silica composite prepared by sol-gel method

Ultrafine Ni_0.8Zn_0.2Fe₂O₄ particles dispersed in silica (SiO₂) matrix are produced by sol-gel method. The powders were subjected to X-ray diffraction to confirm the formation of crystalline phases. The physical properties such as bulk density, true density, % of porosity and % of linear shrinkage were studied. The magnetic permeability as the function of frequency from 1 kHz to 13 MHz and temperatures from room temperature to 300°C were studied for samples sintered at temperature 1250°C. The AC electrical resistivity as the function of frequency and DC electrical resistivity as the function of temperature were studied. The AC-resistivity of the order of 10⁵ cm and DC-resistivity 10⁸ cm were obtained at room temperature. Microstructural features of sintered samples show the presence of ferrite grains of 1–2 m size.     

Folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell composite particles: Synthesis and application in drug release

A drug delivery system was designed by deliberately combining the useful functions into one entity, which was composed of magnetic ZnFe₂O₄ hollow microsphere as the core, and mesoporous silica with folic acid molecules as the outer shell. Amine groups coated magnetic ZnFe₂O₄ hollow microsphere core/mesoporous silica shell (MZHM-MSS-NH₂) composite particles were first synthesized by a one-pot direct co-condensation method. Subsequently a novel kind of folic acid-functionalized magnetic ZnFe₂O₄ hollow microsphere core/mesoporous silica shell (MZHM-MSS-NHFA) composite particles were synthesized by conjugating folic acid as targeted molecule to MZHM-MSS-NH₂. Ibuprofen, a well-known antiphlogistic drug, was used as a model drug to assess the loading and releasing behavior of the composite microspheres. The results show that the MZHM-MSS-NHFA system has the higher capacity of drug storage and good sustained drug-release property.