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超临界流体增强溶液扩散技术制备纳米CL-20及表征 总被引:4,自引:0,他引:4
采用超临界流体增强溶液扩散技术(SEDS法),以乙酸乙酯为溶剂,在9.0 MPa、40℃及溶液质量分数30%、溶液和反溶剂流速分别为5mL/min、8 kg/h的工艺条件下,制备了纳米六硝基六氮杂异伍兹烷(CL-20).用偏光显微镜与扫描电镜(SEM)、激光粒度分析仪、动态颗粒图像分析仪对细化前后的形貌、粒度、粒度分布和球形度进行表征,用傅里叶红外光谱仪(FT IR)和X射线衍射仪(XRD)对纳米CL-20的晶型进行了表征,测试了其热安定性和撞击感度.结果表明,所得CL 20边缘光滑且趋于球形,粒度均匀(1~2μm),所属晶型为β-型,与原料CL-20相比,晶型转变温度推后了约30℃,而分解峰温提前了6.74℃,撞击感度明显降低. 相似文献
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超临界溶液浸渍法(supercritical solution impregnation,SSI)是一种将小分子物质负载到聚合物中的过程技术,主要是利用超临界流体的高扩散系数、低黏度及其对聚合物的溶胀作用,使小分子物质通过分子扩散作用迅速进入溶胀的聚合物并包裹于其中。近年来该技术已用于制备缓释药物/聚合物复合微球、薄膜和纤维等。该法的主要优点在于载体结构灵活,拓展了超临界技术在控释药物制备中的应用。本文主要介绍了SSI法的原理、流程及其在缓释药物制备中的应用,并展望了SSI法的发展趋势。 相似文献
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超临界流体沉析制备微细颗粒的技术及其应用 总被引:11,自引:2,他引:11
快速膨胀超临界流体溶液(RESS)过程和以超临界流体为稀释膨胀剂(GAS)过程是制备微细颗粒的新技术。本文着重分析了用RESS和GAS过程制备微细颗粒的特点及影响因素,介绍了在高分子聚合物、无机盐、陶瓷材料、有机物、药物及含能材料方面的应用,提出超临界流体沉淀技术将成为制备特殊细颗粒材料、超薄膜及提纯热敏性、易氧化物质的有效手段。 相似文献
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超临界流体快速膨胀法制备超细微粒 总被引:3,自引:0,他引:3
超临界流体快速膨胀法(RESS)是一项近10年发展起来的制备超细微粒的新技术,它将溶解有饱和溶质的超临界流体在非常短的时间内(10^-8-10^-5s)通过一个喷嘴(25-60um)进行减压膨胀,利用强烈的机械扰动以达到极高的过饱和度(约10^6)和均相成核条件,从而产生纳米至微米级粒径且粒径及形态分布均匀的超细微粒,该方法已经在制备药物微粒,聚合物微粒和纤维,有机材料和无机材料与陶瓷先驱物等方面得到广泛的应用研究,不仅可以制备单组分的形态不同的微粒或纤维,还可以制备双组分的包覆型微粒,但理论研究目前还处于探索阶段,不能准确解释装置结构参数和操作条件对最终产物形态的影响,在此主要就超临界流体的性质,RESS方法的基本原理,理论和应用研究成果进行简单介绍。 相似文献
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以二氧化碳作为超临界溶剂,采用超临界溶液快速膨胀技术制备得到超细阿昔洛韦药物粒子,在一定的温度和压力情况下,测定了阿昔洛韦在超临界二氧化碳中的溶解度,考察了各种操作参数对药物粒子粒径的影响,研究了药物粒子粒径随各种操作参数的变化规律。结果表明:阿昔洛韦在超临界二氧化碳中的溶解度较小,在10-5~10-6之间(摩尔分率),溶解度随着温度和压力的升高而增大,不存在文献中所报道的反向区。同时实验结果表明:药物粒子粒径变化对预膨胀温度最敏感,粒径随预膨胀温度的升高而减小;一定范围内随收集距离的增大而增大;在萃取温度较低的情况下,粒子粒径基本随着萃取温度的升高而减小;随着萃取温度的升高,在相对较高预膨胀温度下,粒径随着萃取温度升高而增大。 相似文献
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全灿 《中国化学工程学报》2009,17(2):344-349
Based on the solubility in supercritical CO2, two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies. The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 µm can be made via solution enhanced dis-persion by supercritical fluids (SEDS) process, in which CO2 worked as turbulent anti-solvent; while for astaxan-thin, micronized particles with mean particle size of 0.3-0.8 µm were also made successfully by rapid expansion supercritical solution (RESS) process. 相似文献
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设计了预成膜二流式喷嘴用于超临界流体强制分散溶液(SEDS)过程以获得良好的雾化与传质效果。采用预成膜雾化的SEDS(SEDS-PA)过程对胡萝卜素、麻黄素及黄芩甙进行了超细和聚合物包覆实验以考察该法制备药物微粒和载药聚合物微粒的有效性。通过SEM及光学显微镜照片分析微粒形态,用分光光度法检测药物在聚合物微粒中的含量。实验表明,通过SEDS-PA过程可成功地对天然药物超细化,并用聚合物对其包覆,从而制备药物微粒及载药聚合物微粒。 相似文献
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The solubilities of several low-volatility compounds in supercritical fluids were measured. The fluids used were pure carbon dioxide or carbon dioxide modified with small amounts of organic liquids. Some enthalpies of solution of solids in carbon dioxide at a density of 0.80 g/mL are presented. The enthalpy of solution of fluoranthene in carbon dioxide was found to be less endothermic at higher CO2 density. The order of solubilities in the modified fluids was the same as that in the pure liquid modifiers. The same apparatus was used to measure vapor pressures of some substances as well as solubilities. 相似文献
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As particle design is presently a major development of supercritical fluids applications, mainly in the pharmaceutical, nutraceutical, cosmetic and specialty chemistry industries, number of publications are issued and numerous patents filed every year. This document presents a survey (that cannot pretend to be exhaustive!) of published knowledge classified according to the different concepts currently used to manufacture particles, microspheres or microcapsules, liposomes or other dispersed materials (like microfibers):RESS: This acronym refers to ‘Rapid Expansion of Supercritical Solutions’; this process consists in solvating the product in the fluid and rapidly depressurizing this solution through an adequate nozzle, causing an extremely rapid nucleation of the product into a highly dispersed material. Known for long, this process is attractive due to the absence of organic solvent use; unfortunately, its application is restricted to products that present a reasonable solubility in supercritical carbon dioxide (low polarity compounds).GAS or SAS: These acronyms refer to ‘Gas (or Supercritical fluid) Anti-Solvent’, one specific implementation being SEDS (‘Solution Enhanced Dispersion by Supercritical Fluids’); this general concept consists in decreasing the solvent power of a polar liquid solvent in which the substrate is dissolved, by saturating it with carbon dioxide in supercritical conditions, causing the substrate precipitation or recrystallization. According to the solid morphology that is wished, various ways of implementation are available:GAS or SAS recrystallization: This process is mostly used for recrystallization of solid dissolved in a solvent with the aim of obtaining either small size particles or large crystals, depending on the growth rate controlled by the anti-solvent pressure variation rate;ASES: This name is rather used when micro- or nano-particles are expected; the process consists in pulverizing a solution of the substrate(s) in an organic solvent into a vessel swept by a supercritical fluid;SEDS: A specific implementation of ASES consists in co-pulverizing the substrate(s) solution and a stream of supercritical carbon dioxide through appropriate nozzles.PGSS: This acronym refers to ‘Particles from Gas-Saturated Solutions (or Suspensions)’: This process consists in dissolving a supercritical fluid into a liquid substrate, or a solution of the substrate(s) in a solvent, or a suspension of the substrate(s) in a solvent followed by a rapid depressurization of this mixture through a nozzle causing the formation of solid particles or liquid droplets according to the system.The use of supercritical fluids as chemical reaction media for material synthesis. Two processes are described: thermal decomposition in supercritical fluids and hydrothermal synthesis.We will successively detail the literature and patents for these four main process concepts, and related applications that have been claimed. Moreover, as we believe it is important to take into account the user's point-of-view, we will also present this survey in classifying the documents according three product objectives: particles (micro- or nano-) of a single component, microspheres and microcapsules of mixtures of active and carrier (or excipient) components, and particle coating. 相似文献
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Julin García Francisco Rodríguez Juan A Revenga 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2000,75(3):245-251
A Response Surface Methodology approach to correlate the solubility data of solids in supercritical fluids directly to the pressure and temperature is described. Published data for 2,6‐dimethylnaphthalene, 2,3‐dimethylnaphthalene, phenanthrene and benzoic acid in both supercritical carbon dioxide and supercritical ethylene were correlated by means of quadratic models, with R2 statistics greater than 0.99 at more than a 99.9% confidence level. With the developed quadratic models, the solubility for the above‐mentioned solids in both supercritical fluids was predicted with average absolute percentage errors less than 5%. So, this approach to estimate solubility provides a possible guide for saving experimental effort and then giving simple models that could be used for industrial design purposes. © 2000 Society of Chemical Industry 相似文献