W/O微乳液制备纳米羟基磷灰石的影响因素研究

W/O微乳液制备的纳米羟基磷灰石粉体具有颗粒细小、团聚度低、分散性好、表面活性高等优点。综述了W/O微乳液制备纳米羟基磷灰石的原理;重点论述了影响粉体粒径和形貌的水油比、表面活性剂与助表面活性剂类型、前驱物浓度、反应温度等因素;并初步展望了该领域的研究发展趋势。     

空心球羟基磷灰石等离子喷涂粉体的制备

羟基磷灰石等离子喷涂粉体被广泛用于等离子喷涂方法制备的骨及牙等医用种植体表面的生物活性涂层产品中,研制高性能的羟基磷灰石喷涂粉体对提高等离子喷涂羟基磷灰石生物活性涂层的使用性能有着重要意义.本研究采用水热、喷雾造粒、等离子球化及空心化等方法制备出一种新型空心球羟基磷灰石喷涂粉体.扫描电镜照片显示该粉体外观主要呈规则球形,平均粒径约为80.4μm,内部为空心结构,空心部分呈球状位于粉体中心,其平均壳壁厚度约为13.3μm.另外,本工作探讨了团聚结构羟基磷灰石粉体在等离子焰流中的空心化过程,认为粉体的初始孔隙率、粉体在焰流中的熔化程度、熔滴内部的气密性是影响空心化效果的主要因素.最后,通过等离子喷涂方法制备了团聚结构和空心球结构两种羟基磷灰石粉体涂层,结果表明:空心球结构羟基磷灰石粉体涂层的致密性及结合强度均优于团聚结构羟基磷灰石粉体涂层.     

羟基磷灰石的可控制备及其研究

以CTAB为表面活性剂,利用模板技术水热反应合成了平均粒径为68 nm的近球形颗粒和宽为26～35 nm,长为790～960 nm的纳米羟基磷灰石.通过对合成粉体的X射线衍射、红外光谱和透射电镜分析,探讨了CTAB在水热反应中对羟基磷灰石合成的影响机理.结果表明:通过控制反应温度、pH值、反应时间和CTAB的浓度等工艺条件,可以实现纳米羟基磷灰石粒径大小和形貌的可控生长.     

纳米棒状羟基磷灰石的研究进展

综述了形状纳米羟基磷灰石和棒状纳米羟基磷灰石的常用制备方法、各自的优缺点、研究现状及存在的主要问题,即粒子的几何形状不是很均一,晶相稳定性不好;粉体有团聚;粒子纯度及表面的清洁度很差;粒子粒径及粒度分布范围太宽。针对性地提出了采用微波辅助法合成纳米棒状羟基磷灰石。     

碳纳米管的表面改性与羟基磷灰石的包覆

通过TEM、FTIR及XRD等检测手段对原位合成法制备羟基磷灰石/碳纳米管复合材料过程中碳管的表面改性及影响羟基磷灰石包覆的因素进行了系统探讨. 研究表明, 浓酸处理后, 碳纳米管表面产生大量官能团; 阴离子表面活性剂十二烷基磺酸钠(SDS)的加入提高了碳纳米管与水的相容性; 实验中随着(NH₄)₂HPO₄溶液的加入, 羟基磷灰石原位沉积并形成包覆层. 结果发现: 碳纳米管的表面改性、适当的pH值和陈化温度是得到羟基磷灰石连续包覆层的关键因素.     

硅烷偶联剂KH-570表面修饰羟基磷灰石的结构与吸附性能研究

采用硅烷偶联剂KH-570对羟基磷灰石粉体进行表面修饰,使羟基磷灰石在聚合物介质中有较好的相容性和分散稳定性。采用红外光谱、热重、差热、激光粒度、Zeta电位和X射线衍射等方法对表面修饰前后的羟基磷灰石进行表征分析。结果表明,KH-570硅烷偶联剂结合在羟基磷灰石表面,并未对其晶体产生明显影响;羟基磷灰石经修饰后在水溶液中的Zeta电位绝对值增加,分散稳定性提高,粒子团聚程度降低,纳米级颗粒尺寸从272.8nm减小到166nm,Cd2+吸附性能随增重率的增加而降低。     

表面活性剂对羟基磷灰石纤维形貌的影响

以Ca(NO₃)₂·4H₂O和(NH₄)₂HPO₄水溶液为前驱体, 采用水热均相沉淀法制备了结晶度较高的羟基磷灰石纤维, 研究了表面活性剂十六烷基三甲基溴化胺(CTAB)、十二烷基硫酸钠(SDS)和聚乙二醇(PEG)及其含量对产物形貌和相组成的影响。结果表明, 采用这三种表面活性剂制备的产物都是羟基磷灰石, 部分样品含有少量碳酸钙杂质。加入CTAB和SDS均会对纤维的生长起到抑制作用, 得到纤维与球形团聚体并存的产物, 而PEG的加入在一定程度上促进了纤维的生长。     

BaTiO3纳米粉体的制备与表征

采用溶胶 -沉淀工艺制备BaTiO3 纳米粉体 ,探讨了沉淀剂NaOH溶液浓度对制备BaTiO3 粉体相组成的影响 ,提出了溶胶 -沉淀法合成纯相BaTiO3 的反应机理。并对沉淀水洗后的湿凝胶进行表面改性 ,探讨了添加表面活性剂及有机溶剂脱水过程对粉体团聚程度的有效控制     

铁掺杂羟基磷灰石的制备及在强磁场中的定向研究

生物陶瓷表面纳米结构能够影响成骨细胞增殖和分化, 其表面微观结构的控制, 特别是烧结前晶粒取向调控, 是设计开发生物活性陶瓷的关键之一。针对羟基磷灰石晶粒取向调控问题, 重点研究了铁掺杂羟基磷灰石晶体在强磁场中的取向。分别采用共沉淀法和共沉淀-水热法合成了羟基磷灰石(HA)和铁-羟基磷灰石(Fe-HA), 通过XRD、SEM、TEM、PPMS和ICP等对HA和Fe-HA的物相、微观形貌、磁学性能、元素组成进行了表征和分析。研究发现：Fe-HA物相与HA相同, 没有明显的杂质相; HA为抗磁性, Fe-HA转化为顺磁性; 共沉淀法粉体为针状, 共沉淀-水热法粉体为短棒状, 针状粉体在强磁场中不能定向, 短棒状粉体能够定向; 在单一方向强磁场中, HA不能单轴定向, Fe-HA能够在一定程度上沿c轴取向。     

纳米羟基磷灰石粉体的制备及其生物安全性评价

优化溶胶-凝胶法制备纳米羟基磷灰石工艺,试验中添加分散剂聚乙二醇,溶胶经超声震荡、离心洗涤等处理,然后干燥、煅烧,得到纳米羟基磷灰石粉体。通过对产物的XRD、FTIR、SEM及TEM测试,分析其物相组成、颗粒尺寸及微观形态,并经过动物实验来验证其生物安全性。结果表明:该方法制备的纳米羟基磷灰石颗粒细小,添加聚乙二醇并对溶胶进行超声分散可减少纳米羟基磷灰石颗粒的团聚,粉体分散较为均匀,且不影响成分组成。动物实验证明其不致溶血性,在体内无毒、无刺激,具有良好的生物安全性。     

Intrinsic effect of anionic surfactant on the morphology of hydroxyapatite nanoparticles and its structural and biological properties

This paper describes the potential effect of anionic surfactant on the morphology of hydroxyapatite (HA) nanostructures during hydrothermal synthesis. Sodium dodecyl sulfate (SDS) was used as an anionic surfactant. Various concentrations of SDS were used to study morphological changes in HA due to the presence of the surfactant. The final morphology, after treatment by a hydrothermal method, revealed that the anionic surfactant induced growth in one direction (a-axis) and inhibited growth in the other (c-axis) based on the charge distribution on the crystal faces of HA. Further structural analysis (by X-ray diffraction) confirmed this growth along the a-axis. In-vitro cellular analysis revealed that the plate-like nanoparticles possess better bioactivity than their bulk counterparts. Therefore, HA nanoplates could be used for applications that include controlled drug delivery and bone mineralization.     

Synthesis of nanocrystalline hydroxyapatite using surfactant template systems: Role of templates in controlling morphology

Hydroxyapatite (HA) nanopowder was synthesized by reverse microemulsion technique using calcium nitrate and phosphoric acid as starting materials in aqueous phase. Cyclohexane, hexane, and isooctane were used as organic solvents, and Dioctyl sulfosuccinate sodium salt (AOT), dodecyl phosphate (DP), NP5 (poly(oxyethylene)₅ nonylphenol ether), and NP12 (poly(oxyethylene)₁₂ nonylphenol ether) as surfactants to make the emulsion. Effect of synthesis parameters, such as type of surfactant, aqueous to organic ratio (A/O), pH and temperature on powder characteristics were studied. It was found that the surfactant templates played a significant role in regulating the morphology of the nanoparticle. Hydroxyapatite nanoparticle of different morphologies such as spherical, needle shape or rod-like were obtained by adjusting the conditions of the emulsion system. Synthesized powder was characterized using X-ray diffraction (XRD), BET surface area and transmission electron microscopy (TEM). Phase pure HA nanopowder with highest surface area of 121 m²/g were prepared by this technique using NP5 as a surfactant. Densification studies showed that this nanoparticle can give about 98% of their theoretical density. In vitro bioactivity of the dense HA compacts was confirmed by excellent apatite layer formation after 21 days in SBF solution. Cell material interaction study showed good cell attachment and after 5 days cells were proliferated on HA compacts in OPC1 cell culture medium. The results imply this to be a versatile approach for making hydroxyapatite nanocrystals with controlled morphology and excellent biocompatibility.     

Utilization of biowaste eggshells to synthesize nanocrystalline hydroxyapatite powders

Nano hydroxyapatite (HA) powder was successfully synthesized from biowaste chicken eggshells. The nanopowders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), particle size distribution (PSD) analyzer, and Fourier transform infrared spectroscopy (FT-IR) techniques. Selected area electron diffraction (SAED) analysis during TEM showed the particles to be polycrystalline in nature. The resulting HA powder exhibited an average size of ~ 35 nm with a narrowly distributed particle size range from 5 to 90 nm. XRD and FT-IR analysis showed that the powders produced were of high purity. The present study provides a simple sol–gel precipitation method to obtain nano HA powders of high purity from biowaste chicken eggshells.     

前驱物和表面活性剂对等离子体电化学法制备银纳米颗粒的影响

利用等离子体电化学法成功制备出银纳米颗粒,并通过局域表面等离子共振效应对颗粒的生长过程进行实时监测,研究了表面活性剂的浓度、种类和前驱物浓度对银纳米颗粒制备的影响。研究结果表明:增大前驱物或表面活性剂浓度对Ag;还原均有促进作用;与聚乙烯吡络烷酮(PVP)和十六烷基三甲基溴化铵(CTAB)相比较,十二烷基硫酸钠(SDS)作为表面活性剂,在相同时间内,生成的银纳米颗粒数量更多,尺寸和形状分布更均匀。     

Sonochemical synthesis and shape change of colloidal CdSe nanocrystals by high-intensity ultrasound

In this article, we have developed the synthesis of CdSe nanocrystals by the introduction of high-intensity ultrasound combined with an anionic surfactant (sodium dodecyl sulfate, SDS). TEM, XRD, and SEM EDS confirmed the successful synthesis of CdSe nanoparticles with zinc blende crystal phase. UV, PL, and TEM revealed that large particles settled to the bottom of the reaction flask. In the lower part precipitate, nanorods of different aspect ratios were also observed. The CdSe nanorods were formed by self-assembly due to the SDS surfactant and high-intensity ultrasound. A three-stage mechanism for the synthesis of CdSe nanorods was proposed. The effect of SDS concentration on the shape of nanorods was also investigated. At medium concentrations of SDS (0.2 M), one-dimensional CdSe nanorods with different aspect ratios were obtained. When using low concentrations of SDS (0.1 M), two-dimensional square-like crystals were observed due to all growth crystal faces having roughly the same surface energy.     

Evaluation and characterization of nanostructure hydroxyapatite powder prepared by simple sol-gel method

Many attempts have been focused on preparing of synthetic hydroxyapatite (HA), which closely resembles bone apatite and exhibits excellent osteoconductivity. Low temperature formation and fusion of the apatite crystals have been the main contributions of the sol-gel process in comparison with conventional methods for HA powder synthesis. This paper describes the synthesis of nano-HA particles via a sol-gel method. Nanocrystalline powder of hydroxyapatite (HA) was prepared using Ca(NO₃)₂·4H₂O and P₂O₅ by a simple sol-gel approach. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for characterization and evaluation of the phase composition, morphology and particle size of products. The presence of amorphous and crystalline phases in the as-dried gel precursor was confirmed by the evaluating technique. Single phase of HA was also identified in the heat treated powder by XRD patterns. SEM and TEM evaluations showed that the obtained powder after heat treatment at 600 °C was agglomerated and composed of nanocrystalline (25-28 nm) HA particles. Increasing the sintering temperature and time could cause decomposition of HA into β-tricalcium phosphate and calcium oxide. The prepared nanocrystalline HA is able to improve the contact reaction and the stability at the artificial/natural bone interface for medical applications.     

液相沉淀法工艺条件对羟基磷灰石粉体的影响

采用液相沉淀法成功制备纳米羟基磷灰石陶瓷粉体,使用X-射线衍射、扫描电子显微镜等检测手段分析了粉体的组织结构,研究了反应温度、pH值、陈化时间对粉末粒径和物相组成等的影响。结果表明,反应温度为90℃、溶液pH值为10、陈化12 h,在700℃煅烧2 h可制备出高纯度、晶体完整的球形羟基磷灰石粉体,平均尺寸为60 nm。     

Low temperature aqueous precipitation of needle-like nanophase hydroxyapatite

The use of tissue engineered biodegradable porous scaffolds has become an important focus of the biomedical research field. The precursor materials used to form these structures play a vital role in their overall performance thus making the study and synthesis of these selected materials imperative. The authors present a comparison and characterisation of hydroxyapatite (HA), a popular calcium phosphate (CaP) biomaterial, synthesised by an aqueous precipitation (AP) method. The influence of various reaction conditions on the phase, crystallinity, particle size as well as morphology, molecular structure, potential in-vivo bioactivity and cell viability were assessed by XRD, SEM and TEM, FTIR, a simulated body fluid (SBF) test and a live/dead assay using MC3T3 osteoblast precursor cells, respectively. Naturally carbonated nanoparticles of HA with typically needle-like morphology were synthesised by the reported AP method. Initial pH was found to influence the crystallisation process and determine the CaP phase formed as well as the resultant particle and crystallite sizes. A marked change in particle morphology was also observed above pH 9. The use of toluene as a replacement solvent for water up to 60 % was found to reduce the crystallinity of as-synthesised HA. This has marked influence on the effect of ethanolamine (5 wt%), which was found to improve HA crystallinity. SEM and EDS were used to confirm the growth of carbonated apatite on the surface of HA pellets immersed in SBF for up to 28 days. Cell culture results revealed viable cells on all samples where pH was controlled and maintained at 10–11 during precipitation, including those that used ethanolamine and toluene in preparation. When the initial alkali pH was not maintained non-viable cells were observed on HA substrates.     

Characterization and dissolution properties of ketoprofen in binary and ternary solid dispersions with polyethylene glycol and surfactants

The effect of incorporation of an anionic [sodium dodecyl sulfate (SDS) or dioctylsulfosuccinate (DSS)] or nonionic [Tween 60 (TW60)] surfactant on the properties of ketoprofen solid dispersions in polyethylene glycol 15000 (PEG) has been investigated. Physicochemical and morphological properties of the various solid systems were determined by differential scanning calorimetry, hot stage microscopy, X-ray powder diffraction analysis, and scanning electron microscopy. The results from dissolution studies, performed according to the USP 24 basket method, indicated that all ternary dispersed systems were significantly (p < 0.001) more efficacious than the corresponding binary ones, by virtue of the additive wetting and solubilizing effect due to the presence of the surfactant. The relative effectiveness of the incorporated surfactant was in the same order as found in phase-solubility studies (i.e., SDS > DSS > TW60). With regard to the solid dispersion preparation method, coevaporated products always gave better results than the corresponding cofused ones; however, this effect was statistically significant (p < 0.001) only in the initial phase of the dissolution process. The most effective solid dispersion was the 10-80-10 w/w drug-PEG-SDS ternary coevaporate, which allowed dissolution of 50% drug after only 6 min (in comparison with > 120 min for drug alone and 17 min for the binary coevaporate) and dissolution of about 100% drug after 30 min (in comparison with > 120 min for the binary coevaporate).     

Morphological study of hydroxyapatite nanocrystal suspension

Nanometer size hydroxyapatite (HA) crystals are prepared by a wet chemical precipitation method at different synthesis temperatures and with various reactant addition rates. The resulting aqueous suspensions are studied in terms of morphology (transmission electron microscope, specific surface area), phase (X-ray diffraction, electron diffraction and infrared spectroscopy) and rheological properties. This work shows that shape, size and specific surface area of the HA nanoparticles are very sensitive to the reaction temperature and also to the reactant addition rate. The measured pH at the end of synthesis, which is strongly linked with the reactant addition rate, is a key parameter which can be used to determine the purity of the synthesized HA nanocrystal and also for the stabilization (dispersion) of the suspension. HA nanoparticles synthesized at low temperature (T < 6°C) are monocrystalline. A transition temperature (T=60 °C) can be defined as a limit for the synthesis of monocrystalline HA nanocrystals, above this critical temperature nanocrystals become polycrystalline. HA monocrystals adopt a needle shape and are oriented following the c-axis of the hexagonal HA structure. The as-synthesized suspension is then concentrated and the effect of a dispersing agent addition, which is needed to get a high solid/liquid ratio coupled with good flowability of the suspension, is also shown, because this suspension is used in the suspension plasma spraying process.