均匀沉淀法制备不同粒径的纳米氧化锌

由于纳米氧化锌的功能和用途不同,因而需要制备出不同平均粒径的纳米氧化锌。论文以六水硝酸锌为原料,尿素为沉淀剂,研究了均匀沉淀法制备不同平均粒径纳米氧化锌的工艺条件,讨论了工艺条件对其粒径和产率的影响规律。结果表明:通过均匀沉淀法制备的纳米氧化锌的前驱体为Zn5(OH)6(CO3)2;制备的纳米氧化锌为六方晶系的球形颗粒,平均粒径为20～50nm;纳米氧化锌的产率随反应物浓度的增大、反应温度的升高、反应配比(n尿素/nZn2+)的增大而增大;纳米氧化锌颗粒的平均粒径随反应物浓度的减小、反应温度和煅烧温度的降低而减小。     

加压碳化体系对纳米碳酸钙粒度和分散性的影响

利用加压碳化体系制备粒径均一、高分散性纳米碳酸钙材料。考察氢氧化钙浓度、表面活性剂添加量、反应温度、CO2压力对制备纳米CaCO3粒子尺寸和分散程度的影响,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、Zeta电位和傅立叶变换红外光谱(FT-IR)对制备的纳米碳酸钙粒子进行表征。结果表明,最优加压碳化反应条件是Ca(OH)2质量浓度为2%、表面活性剂添加量为3%(占碳酸钙理论产量的百分比)、反应温度为40℃、CO2压力为6 MPa,所得立方形碳酸钙平均粒径为117 nm,晶型为方解石型碳酸钙。碳化反应加入表面活性剂十六烷基三甲基溴化铵(CTAB)使CaCO3表面形成的正电荷增大至+37.7 mV并高于标准值30 mV,表明制备的CaCO3产品具有良好的分散性且稳定。通过FT-IR和Zeta电位对CTAB改性前后CaCO3纳米粒子进行表征,探讨了CTAB对合成纳米CaCO3分散性的影响机理,为纳米碳酸钙制备提供了一种新的方法。     

SEDS技术制备水飞蓟素纳米颗粒

采用超临界流体增强溶液分散技术(SEDS)从丙酮溶液中沉淀制备水飞蓟素纳米颗粒,用扫描电镜考察了工艺参数温度(25℃,32℃,40℃,50℃)、压力(9.5MPa,12MPa,15MPa,20MPa)、溶液浓度(40mg.mL-1,60mg.mL-1,80mg.mL-1,100mg.mL-1,120mg.mL-1)对颗粒形貌、粒径尺寸及粒径尺寸分布的影响。结果表明,所得颗粒均为实心微球;温度和溶液浓度是影响粒径尺寸的主要因素,降低温度和浓度能够显著减小粒径尺寸;温度也对粒径尺寸分布影响显著,在40℃时,粒径尺寸分布较窄,当温度高于或低于40℃时,粒径尺寸分布明显变宽。通过优化工艺参数,在9.5MPa,40℃,60mg.mL-1的条件下,制备出粒径尺寸介于100~300nm的水飞蓟素纳米颗粒。     

疏水改性核壳结构颗粒对Pickering乳液的稳定作用

为了探究固体颗粒对乳液的稳定作用,采用双亲染料分子罗丹明B对核壳结构的Fe_3O_4@SiO_2纳米颗粒进行疏水改性,并将改性后的纳米颗粒作为稳定剂制备Pickering乳液。通过Zeta电位、FTIR、XRD、SEM、接触角测量、光学显微镜、电导率仪对Fe_3O_4@SiO_2纳米颗粒以及Pickering乳液的结构、形貌和性能进行表征与分析,结果表明:制备的纳米颗粒粒径小,约为150 nm,为单分散球形核壳结构;罗丹明B成功修饰到Fe_3O_4@SiO_2纳米颗粒表面,改性后颗粒接触角由30°增加至120°;随乳化剂颗粒质量浓度的增加,制备的乳液液滴的粒径减小。另外,所得Pickering乳液具有良好的磁场响应性,可通过外加磁场实现对乳液稳定性的可逆调控,且此过程可重复3次以上。     

焦磷酸钠对改性膨润土分散性的影响

膨润土/改性膨润土分散体系可用于制备水性仿石涂料。通过焦磷酸钠作为分散剂对膨润土水溶液进行改性,研究了焦磷酸钠对膨润土结构的影响,并研究了膨润土浓度(5%~10%)对分散体系结构的影响,采用X射线衍射(XRD)、傅里叶红外光谱(FT-IR),激光粒径分布和Zeta电位对溶液以及烘干后的粉末的结构进行表征。结果表明:焦磷酸钠和膨润土的比例在1∶10左右时,晶面间距小,溶液的Zeta电位最低;采用该比例焦磷酸钠分散改性膨润土,改性膨润土浓度对该分散体系结构的影响是,随着改性膨润土浓度的增加,晶面间距先减小后增大,溶液中平均粒径呈现增大的趋势。而焦磷酸钠与膨润土之间存在氢键作用。     

水溶性丁二酸酐酰化壳聚糖纳米凝胶的制备及其pH响应性研究

以水为介质、碳酸钠为催化剂,室温下制备了水溶性丁二酸酐酰化壳聚糖,研究了反应物料比对产物酰化取代度及水溶性的影响。红外光谱分析表明丁二酸酐成功接枝到了壳聚糖分子链上;XRD结果表明酰化反应改变了壳聚糖的结晶结构;Zeta电位分析发现存在1个等电点:pI=3.54。将丁二酸酐酰化壳聚糖加入到甲酸溶液中,通过自组装法制备纳米凝胶粒子。SEM照片显示该纳米凝胶粒子呈球形,粒径为20~30nm;DLS测试表明,随溶液pH值的增大,粒径从70~80nm增大到350~700nm,表明丁二酸酐酰化壳聚糖纳米凝胶粒子具有一定的pH响应性。     

空气纳米气泡的稳定性及理化特性

空气纳米气泡（Air-NBs）的理化特性是其广泛应用的基础。本文利用纳米粒度-zeta电位分析仪研究了水力空化原理产生的Air-NBs的理化特性,即粒径分布和zeta电位,考察了装置运行压力、电解质浓度、pH和温度对Air-NBs理化特性的影响;同时考察了去离子水和CaCl₂溶液中Air-NBs稳定性。结果表明：纳米气泡发生器的压力越大,其产生的Air-NBs的小粒径比例更大,且电解质的加入有助于气泡粒径的缩小。随着溶液中电解质浓度、pH和温度的升高,溶液中Air-NBs的平均粒径逐渐减小,但气泡间的聚结作用会导致其粒径随时间逐渐增大;通过对两种溶液中Air-NBs粒径的实时监测发现其能在溶液中存在5天之久。胶体稳定（DLVO）理论和zeta电位效应可以合理阐释溶液中Air-NBs的稳定性。     

溶胶-凝胶法制备粒径可控的纳米钛酸铅

纳米钛酸铅是一种应用广泛的压电材料。采用溶胶-凝胶法研究了纳米钛酸铅的制备,考察了凝胶的煅烧温度、反应物的浓度及溶胶的反应温度对纳米颗粒粒径的影响和变化规律。研究表明,控制钛酸丁酯-醇溶液浓度为0.100～1.000 mol/L、醋酸铅-醋酸浓度为0.500～1.500 mol/L、溶胶反应温度为70～90℃、凝胶煅烧温度为400～800℃,可制备出平均粒径在20～50 nm范围的近似球形的四方相纳米钛酸铅。制备条件对纳米钛酸铅的粒径有显著影响:随溶胶反应温度和凝胶煅烧温度的升高,所制备纳米钛酸铅平均粒径增大;当醋酸铅-醋酸溶液浓度为1.500 mol/L,随钛酸丁酯-醇溶液浓度由0.100 mol/L增大至1.000 mol/L,所制备纳米钛酸铅粒径先增大后减小。制备粒径可控的纳米钛酸铅对其性能及应用具有重要的价值。     

超重力液相沉淀法制备纳米铁酸钴

针对磁力搅拌器制备纳米材料时存在粒径分布宽、分散不均匀的问题,采用撞击流-旋转填料床结合化学共沉淀法,以Fe（NO₃）₃·9H₂O、Co（NO₃）₂·6H₂O、NaOH为原料制备CoFe₂O₄纳米颗粒。研究了转速、液体流量、NaOH浓度以及晶化时间对CoFe₂O₄纳米颗粒粒径的影响;并与磁力搅拌器制备的CoFe₂O₄纳米颗粒在磁性能方面进行了对比。采用X射线衍射仪（XRD）、傅里叶红外光谱仪（FTIR）、透射电镜（TEM）、纳米粒度仪及振动样品磁强计（VSM）对产物的粒径形貌及磁性能进行表征。结果表明：CoFe₂O₄纳米颗粒的粒径随转速、液体流量和NaOH浓度的增加而减小,但随晶化时间的增加而增大。最佳工艺条件为：转速900r/min,液体流量60L/h,NaOH浓度3mol/L,晶化时间6h。此条件下制备的CoFe₂O₄纳米颗粒的粒径约为20nm,饱和磁化强度为75.43emu/g,较磁力搅拌器提高40%。     

超临界乳液萃取法制备载槲皮素微胶囊

采用超临界乳液萃取法(SFEE)制得载槲皮素微胶囊,系统考察了制备过程中萃取温度、压力、CO2流速、配制乳液参数对溶剂残留与微胶囊粒径的影响。采用顶空气相色谱法、场发射扫描电镜、Zeta电位、FTIR对溶剂残留与微胶囊进行表征。结果表明:在313 K、9 MPa、CO2流速为0.4 L/min的条件下,处理40 min,溶剂残留可低至59 mg/L。壁材质量浓度从10 g/L增加至100 g/L时,微胶囊粒径由0.9μm升至3.7μm。与溶剂蒸发法相比,SFEE法可在短时间内有效去除有机溶剂,所制备的微胶囊球形度高,界面清晰,在水中稳定性好。     

A novel preparation method for 5-aminosalicylic Acid loaded eudragit s100 nanoparticles

In this study, solution enhanced dispersion by supercritical fluids (SEDS) technique was applied for the preparation of 5-aminosalicylic acid (5-ASA) loaded Eudragit S100 (EU S100) nanoparticles. The effects of various process variables including pressure, temperature, 5-ASA concentration and solution flow rate on morphology, particle size, 5-ASA loading and entrapment efficiency of nanoparticles were investigated. Under the appropriate conditions, drug-loaded nanoparticles exhibited a spherical shape and small particle size with narrow particle size distribution. In addition, the nanoparticles prepared were characterized by X-ray diffraction, Differential scanning calorimetry and Fourier transform infrared spectroscopy analyses. The results showed that 5-ASA was imbedded into EU S100 in an amorphous state after SEDS processing and the SEDS process did not induce degradation of 5-ASA.     

Application of organic nonsolvent in the process of solution-enhanced dispersion by supercritical CO2 to prepare puerarin fine particles

An organic nonsolvent, dichloromethane was employed in the process of solution-enhanced dispersion by supercritical CO₂ (SEDS) to prepare fine particles of puerarin. A 2³ factorial experiment was designed to investigate and identify the relative significance of the processing parameters on the surface morphology, particle size and particle size distribution of the products. The effect of the nonsolvent/solvent ratio was found to be dominant in the results regarding particle size. Increasing the nonsolvent content of the puerarin solution decreased the particle size significantly. After optimization, the resulting puerarin nanoparticles exhibited a good spherical shape, a smooth surface and a narrow particle size distribution, with a mean particle size of 0.19 μm. After SEDS processing, the measurements of high performance liquid chromatography (HPLC), ultraviolet (UV) and mass spectrometry (MS) indicated there was no change in the chemical composition of puerarin particles; Fourier transform infrared (FTIR) spectroscopy measurement found the minor structural changes occurred on a molecular level; X-ray powder diffraction (XRPD) analysis revealed that the physical state of puerarin shifted into an amorphous form; and a significant increase in the dissolution rate of puerarin nanoparticles was observed. The SEDS process combined with the addition of dichloromethane could produce puerarin nanoparticles without contamination.     

Preparation of non-woven mats from all-aqueous silk fibroin solution with electrospinning method

In the present study, we successfully prepared non-woven mats from stable regenerated silk fibroin aqueous solution at high concentration. Scanning electronic microscope (SEM) was used to observe the morphology of the fibers. The structure of the fibers was characterized using Fourier transform infrared (FTIR), wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The mechanical tests were also performed. In the as-spun fibers, silk fibroin was present in a random coil conformation, the stress and strain at break were 0.82 MPa and 0.76%, respectively, while after methanol treatment, the silk fibroin was transformed into a β-sheet-containing structure, the stress and strain at break increased to 1.49 MPa and 1.63%, respectively. This study provided an option for the electrospinning of silk fibroin without using organic solvent or blending with any other polymers, which may be important in tissue engineering scaffold preparation.     

Production of silk fibroin nanoparticles using ionic liquids and high‐power ultrasounds

Biopolymeric nanoparticles have attracted great research interest in the last few years due to their multiple applications. This article describes how high‐power ultrasounds are capable of enhancing the dissolution process of silk proteins in ionic liquids (ILs) and how silk fibroin nanoparticles (SFNs) can be obtained directly from the silk/ionic liquid solution (SIL) by rapid desolvation in polar organic solvents. The silk fibroin integrity is highly preserved during the dissolution process, as confirmed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) of the SIL. These regenerated SFNs are insoluble in water and other common organic solvents and are indistinguishable from the classical SFNs with respect to their diameter (180 ± 5 nm), Zeta potential (?25 ± 3 mV), high degree of β‐sheet and low cytotoxicity. Large amounts of silk can be turned into biomaterials directly from the SIL solution for use in a wide range of applications, while the ILs can be recovered from the coagulant solution under reduced pressure and reused without loss of their solvent properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41702.     

离子液体对丝素蛋白溶解性能的影响

合成了一系列碱性离子液体,其中离子液体1-丁基-3-甲基咪唑乙酸盐([Bmim]AC)对丝素蛋白具有良好的溶解性能。考察了丝素蛋白在该离子液体中的溶解特性及在离子液体中的溶解温度和溶解时间,结果表明,在75℃下,溶解840 min,该离子液体对丝素蛋白的溶解能力达到15%(质量分数)。XRD和FTIR分析表明,再生丝素蛋白的构象以α-螺旋为主,丝素蛋白在溶解过程中没有发生衍生化。因此,[Bmim]AC离子液体是丝素蛋白的优良溶剂。     

Production of dye nanoparticles via a supercritical gas anti-solvent process and optimisation of the process conditions

Nanoparticles of dyes and pigments with high quality and efficiency can be successfully used in the supercritical dyeing process of the textile industries, which is introduced as a waterless and greener dyeing method. In this study, nanoparticles of the Quinoline yellow dye, known as colour index (CI) Solvent Yellow 33, were precipitated via the supercritical gas anti-solvent (GAS) process. This process was performed at various pressures (100, 130, and 150 bar), temperatures (308, 318, and 328 K), and solute concentrations (10, 30, and 50 mg/ml), designed by the Box–Behnken design (BBD) method. It was found that increasing the pressure, reducing the temperature, and reducing the initial concentration of the liquid solution provided favourable conditions for the production of nano-sized particles with narrow size distribution and uniform morphology. Accordingly, the optimum operating conditions of the GAS process which resulted in precipitation of the dye nanoparticles, with a mean particle size of 125 nm, were determined at a temperature of 318 K, pressure of 150 bar, and the initial concentration of 10 mg/ml. The characteristics of the precipitated particles were analysed with high-performance liquid chromatography (HPLC), field-emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR) spectrometry analysis. Based on the DSC and XRD results, GAS processed samples have lower crystallinity and lower particle size. Also, nano-metric size and narrow size distribution of the precipitated dye particles were confirmed through the FESEM and DLS results.     

乳液聚合法制备PSA纳米微球与PS纳米微球的性能测定

以苯乙烯(St)和甲基丙烯酸(MAA)为原料,采用乳液聚合法共聚制备羧基化聚苯乙烯(PSA)纳米微球。通过改变乳化剂(SDS)的用量、St/MAA的质量配比控制微球性质和大小。利用透射电镜(TEM)、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、差示扫描量热仪(DSC)、热重分析仪(TGA)和Zeta电位仪对PSA纳米微球进行表征。FTIR结果证实MAA成功引入到微球中,TEM和SEM表明当乳化剂用量为单体总质量的10%时,得到大小均匀,直径为45 nm的PSA微球。PSA的玻璃化转变温度和热分解温度随MAA的含量增加而提高。纯PS表面带负电荷,Zeta电位为-17 mV。共聚后的PSA纳米颗粒,其St与MAA物质的量比为10/1. 0,10/1. 5和10/2. 5时,Zeta电位分别为-31. 9、-39. 6和-44 mV。上述结果表明,采用共聚是调节PS微球热性质及表面性质的有效途径。     

用含夹带剂丙酮的超临界CO2快速膨胀法制备灰黄霉素的微细颗粒

Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducingparticle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect ofpre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on theprecipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated byRESS was less than 1.2 μm. An increase in pre-expansion pressure, extraction temperature, spraying distance andconcentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With thedecrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material andthe processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphologyof particles precipitated was analyzed by scanning electron microscopy (SEM).     

硫酸法水解家蚕丝及其光谱性质研究

文章用一定质量分数的硫酸溶液对家蚕丝进行水解,并利用傅里叶红外光谱仪、紫外可见分光光度计、X-射线衍射仪和扫描电镜等先进测试方法对硫酸水解家蚕丝制取丝素肽进行测试,分析家蚕丝丝素多肽的结构,为以后在食品、药品、化妆品等领域的应用提供理论数据。