T型微通道装置制备尺寸均一壳聚糖微球

采用T型微通道装置制备尺寸均一的壳聚糖微球. 研究了乳化剂用量、油水两相流速比和流速等条件对乳液粒径的影响,尝试制备了不同分子量的壳聚糖乳液,并确定了交联固化方式. T型微通道装置的油相通道直径350 mm,水相通道直径65 mm,两通道接口处直径16 mm. 以1.5%(w)的壳聚糖醋酸水溶液为水相,以液体石蜡/石油醚(7/5, j)的混合物作为油相,水相流速20 mL/min,油水两相流速比为15:1,4%(w)的PO-500作为油相乳化剂,制备得到的壳聚糖乳液粒径分布系数<10%. 以戊二醛的甲苯溶液作为交联剂,当戊二醛所含醛基与壳聚糖所含氨基的摩尔比为1:1时,交联时间选择2 h.     

微孔膜乳化与悬浮聚合结合法制备均一PST-DVB多孔微球

使用自制的微孔膜乳化装置,通过微孔膜乳化结合悬浮聚合方法,批量制备了微米级的聚(苯乙烯-二乙烯基苯)(PST-DVB)微球. 实验中采用孔径为5.2 mm的微孔膜,考察了膜线剪切力、管线速度和膜乳化压力对微球粒径及其分布的影响,以及膜乳化压力和膜线剪切力对分散相流速的影响. 研究结果表明,膜线剪切力在合适的范围内对微球粒径影响不大,而管线速度在14.38~26.49 m/min之间、膜乳化压力在0.008~0.012 MPa之间时,所制备微球的尺寸均一. 研究还发现膜乳化压力是影响分散相流速的最主要因素. 研究结果为装置的规模化放大奠定了理论基础.     

旋转膜乳化法制备均一魔芋葡苷聚糖凝胶微球

以天然多糖魔芋葡苷聚糖(KGM)为材料,采用旋转膜乳化法结合化学交联法制备均一的魔芋葡苷聚糖凝胶微球,以3种不同粘度的12%(w) KGM水溶液为分散相(水相)、液体石蜡(LP):石油醚(PE)混合油相为连续相,考察了乳化剂种类对KGM乳液稳定性的影响及水相粘度、油相配比和膜管转速对KGM成球的影响. 结果表明,KGM水相粘度越高,相应的最佳油相粘度越低,最佳KGM水相粘度为1548 mPa×s,最佳油相体积比为LP:PE=5:1,最优膜管转速为400 r/min,利于KGM乳液稳定的乳化剂是4%(w) Span 80. 该条件下制得粒径约70 μm、粒径分布系数Span<1.0的均一KGM微球.     

快速膜乳化法制备尺寸均一的载硫酸亚铁明胶微球

采用快速膜乳化技术,以大豆油为油相、葡萄糖为固化剂,制备均一载硫酸亚铁明胶微球,考察了制备参数对明胶微球形貌和均一性的影响. 结果表明,优化的制备参数为明胶溶液浓度0.200 g/mL、乳化剂浓度0.07 g/mL、初乳均质转速10000 r/min、固化反应时间20 min. 在该条件下制备了球形圆整、平均粒径为50 μm的均一载FeSO4明胶微球,FeSO4包埋率达44.12%,Fe2+含量为60.8%.     

快速膜乳化技术制备均一小粒径复合多糖微球及其色谱性能评价

采用快速膜乳化技术制备均一小粒径复合多糖微球,重点探究膜乳化工艺关键参数和微球固化冷却工艺等对微球形貌、粒径及其分布的影响,以及制备工艺对微球耐压性能的影响,在此基础上制备粒径均一、耐压性能良好的小粒径复合多糖微球。色谱研究表明,该均一小粒径复合多糖微球具有较高的色谱分离度,在高分辨率色谱领域具有良好的应用前景。     

快速膜乳化法制备尺寸均一PELA多孔微球及其孔径调控

采用快速膜乳化法,以二氯甲烷为油相,通过溶剂挥发制孔,在室温下制备了一系列聚乙二醇-聚乳酸共聚物(PELA)多孔微球. 结果表明,优化的制备条件为：搅拌速度250 r/min、油相中PELA浓度50 g/L、水/二氯甲烷/PVA水溶液体积比1:2.5:25及mPEG:PLA分子量比1:14,在该条件下可制备粒径均一、尺寸可控的PELA多孔微球,且孔径较大,孔径最大为15.0 nm,属介孔材料,可用于蛋白多肽类药物的吸附.     

微球材料尺寸和结构控制的过程工程

微球材料的粒径均一性和结构可控性直接影响其应用效果,这对过程工程提出了挑战。在发展微孔膜乳化过程制备均一乳液和微球的基础上,对均一乳液的形成机理进行了研究,通过对液滴形成过程的控制,在油/水、水/油、水/油/水等体系成功制备出了均一微球。通过发展微球结构演变过程的定量研究方法,成功对微球结构进行了调控;针对生化工程对超大孔微球的重要需求,发展了超大孔微球制备方法,实现了孔径在100 nm到微米级的调控。研究了粒径均一性和结构对其应用效果的影响。微球应用于生物分离介质时,粒径均一性提高了蛋白质的分离度;超大孔微球可使超大生物分子快速进入介质内部,显著提高纯化回收率。微球应用于胰岛素口服药物载体时,粒径对其在消化道的分布有显著影响,中空-多孔微球显示了最佳的降血糖效果。     

膜乳化法与复乳法结合制备粒径均一的PELA载溶菌酶微球

采用快速膜乳化技术与复乳-溶剂去除法制备了尺寸均一的单甲氧基聚乙二醇-聚-DL-乳酸(PELA)载溶菌酶微球,比较了膜材种类和有机溶剂类型对微球中药物包埋率和活性保持的影响. 研究结果表明,该方法能快速制备粒径均一的载药微球,在油相与外水相体积比为1:6的条件下,微球粒径分布系数小于20%,而且该方法对膜材和有机溶剂有很好的普适性. 以PELA为膜材、乙酸乙酯为有机溶剂,采用溶剂扩散法制备的载药微球包埋率高达95.7%,并且能保持高的活性.     

微球材料尺寸和结构控制的过程工程

微球材料的粒径均一性和结构可控性直接影响其应用效果,这对过程工程提出了挑战。在发展微孔膜乳化过程制备均一乳液和微球的基础上,对均一乳液的形成机理进行了研究,通过对液滴形成过程的控制,在油/水、水/油、水/油/水等体系成功制备出了均一微球。通过发展微球结构演变过程的定量研究方法,成功对微球结构进行了调控;针对生化工程对超大孔微球的重要需求,发展了超大孔微球制备方法,实现了孔径在100 nm到微米级的调控。研究了粒径均一性和结构对其应用效果的影响。微球应用于生物分离介质时,粒径均一性提高了蛋白质的分离度;超大孔微球可使超大生物分子快速进入介质内部,显著提高纯化回收率。微球应用于胰岛素口服药物载体时,粒径对其在消化道的分布有显著影响,中空-多孔微球显示了最佳的降血糖效果。     

均一粒径BaSO4微球的合成及产率

以BaCl_2、Na_2SO_4为原料,乙二胺四乙酸二钠(EDTA×2Na)为络合剂,采用络合法合成了均一粒径的BaSO_4微球,并利用XRD、FTIR、XRF、SEM及DLS对BaSO_4微球进行了表征。考察了EDTA×2Na用量、反应物浓度、反应温度、二次调节pH对BaSO_4微球形貌和产率的影响。BaSO_4微球合成的最佳条件为:c(BaCl_2)=1.0mol/L,n(EDTA×2Na)∶n(BaCl_2)∶n(Na_2SO_4)=1∶1∶1,反应温度55℃,pH=9.0。结果表明:合成产物是BaSO_4,单分散且粒径在1.3~1.8μm范围内的微球占总颗粒数量的47.01%,产率为74.15%。二次调节pH=7.0可将BaSO_4的收率由74.15%提高至87.88%,但除了获得粒径1.5~2μm的BaSO_4微球外,还会获得大量亚微米级BaSO_4颗粒,导致产物粒径均一性下降。     

膜乳化法原理及其制备单分散高分子微球的进展

介绍了膜乳化法的原理及其影响因素,由膜乳化法制备的单分散高分子微球具备粒径均一、分布可控等特点;综述了由膜乳化法制备的单分散高分子微球在化妆品、生物医药、化工等相关领域的应用研究进展.     

粒度在线检测技术在微球催化剂装置的应用

微球催化剂装置使用在线湿法粒度仪作为产品粒度分布在线监测手段,通过实时分析结果及时反馈产品粒度分布,以便及时调整操作条件,保证催化剂产品粒度分布合格。通过对比在线湿法粒度仪分析结果与班样的分析结果,得出满足装置需要的在线湿法粒度仪在线分析参考值:(0~20) μm为4.3%~4.8%,(0~40) μm为 22.0%~22.8%,(0~149) μm为92.0~92.6%,该条件下生产的催化剂产品的粒度分析结果可以满足生产需要。     

膜法制备乳状液研究进展

膜法制乳是靠膜两侧的压差使分散相通过微孔膜,以小液滴的形式分散在连续相中而形成乳状液的方法。与转-定体系、高压均化等传统方法相比,该法液滴尺寸均一、节能、剪应力小,可应用于化妆品、食品、医药等领域,其中一些应用已经工业化。液滴从膜孔中形成和分离依赖于各种过程参数(如过膜压差、膜表面连续相的剪切应力)、膜材料和结构。很多实验研究集中在膜乳化过程参数的影响上,膜乳化过程的机理尚需进一步完善。     

Emulsification of a viscous monomer mix: Particle size and size distribution

A non-Newtonian mixture of monomers, their copolymer and pigment was dispersed into water with emulsifier by a rotor-stator homogenizer (Brinkmann Polytron). Volume median diameters d₅₀ of the droplets, measured by Coulter Counter or optical microscopy, were typically 4–20 μm; d₅₀ was about inversely proportional to monomer fraction (0.2 to 1.0), or to rotor speed (4000 to 11000 rpm). Increasing the emulsifier from 0.1 % to 3% roughly halved d₅₀; volume fraction of organic phase had little effect. Turbulent dispersion theory (Calabrese et al., 1986a, b), adapted to non-Newtonian drops, represented the data but with different numerical constants. A high geometric standard deviation, around 1.7 but increasing slightly as monomer fraction decreased, may be due to non-uniform turbulence and to the complexity of breakup at high viscosity.     

Design and fabrication of whisker hybrid ceramic membranes with narrow pore size distribution and high permeability via co-sintering process

Ceramic microfiltration membranes (MF) with narrow pore size distribution and high permeability are widely used for the preparation of ceramic ultrafiltration membranes (UF) and in wastewater treatment. In this work, a whisker hybrid ceramic membrane (WHCM) consisting of a whisker layer and an alumina layer was designed to achieve high permeability and narrow pore size distribution based on the relative resistance obtained using the Hagen-Poiseuille and Darcy equations. The whisker layer was designed to prevent the penetration of alumina particles into the support and ensure a high porosity of the membrane, while the alumina layer provided a smooth surface and narrow pore size distribution. Mass transfer resistance is critical to reduce the effect of the membrane layers. It was found that the resistance of the WHCM depended largely on the alumina layer. The effect of the support and whisker layer on the resistance of the WHCM was negligible. This was consistent with theoretical calculations. The WHCM was co-sintered at 1000?°C, which resulted in a high permeability of ~?645?L?m^?1 h^?1 ;bar^?1 and a narrow pore size distribution of ~?100?nm. Co-sintering was carried out on a macroporous ceramic support (just needed one sintering process), which greatly reduced the preparation cost and time. The WHCM (as the sub-layer) also showed a great potential to be used for the fabrication of ceramic UF membranes with high repeatability. Hence, this study provides an efficient approach for the fabrication of advanced ceramic MF membranes on macroporous supports, allowing for rapid prototyping with scale-up capability.     

Preparation of natural microcrystalline graphite with high sphericity and narrow size distribution

Natural microcrystalline graphite with high sphericity and narrow size distribution was prepared by powder engineering methods. The shape of microcrystalline graphite (MCG) particles was modified using a wet agitating method and then the particles were separated into groups with narrow size distribution by means of gravity settling and hydrocyclone combined. Several methods such as scanning electron microscope (SEM), Raman spectroscopy and X-ray diffraction (XRD) were employed to investigate the structure of the sample. The result showed that the present method was effective in classifying the MCG particles into a narrow size range. Galvanostatic cycling was used to investigate the electrochemical performance of the as-prepared MCG as the anode material of lithium ion cells. Compared with raw MCG, the modified MCG shows a large improvement in reversible capacity, though the cycleability is slightly reduced.     

逐层自组装法制备纳米二氧化钛空心微球

本文采用溶胶-凝胶法与自组装技术相结合的工艺,以聚乙二醇为模板制备了多层组装的TiO2空心微球。采用TEM对产物进行了表征。以甲基橙溶液的脱色降解率,考察了不同煅烧温度和组装层数对TiO2空心微球光催化性能的影响。结果表明：500℃煅烧下组装四层的TiO2空心微球光催化效果最佳,2h内对甲基橙的催化效果可达到97.25%。     

Low-temperature synthesis of bioactive glass-ceramic microspheres: Effect of processing parameters on the size and morphology

A low-temperature method was developed to produce bioactive glass microspheres (BGMs). The microspheres were fabricated by dispersing the prepared sol in silicon oil, a process called the sol-microemulsion-gel method. The resulting microspheres were characterized by X-ray diffractometry (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Brunauer-Emmett-Teller (BET) techniques. Furthermore, the effect of various processing parameters such as reaction chamber size and the stirring rate on microspheres diameter was investigated. The results indicated that under optimized conditions, one could obtain BGMs with acceptable sphericity having a narrow size distribution. The obtained microspheres had diameters in the range of 19.3 ± 9.3 μm. The BET specific surface area was 240.33 m²/g. The results also showed that the increase in the reaction chamber size had interesting contradictory effects on BGMs diameter. The increase in the stirring rate intensified the shear forces exerted on the water-based phase and caused the generation of smaller droplets and microspheres.