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超临界状态下微胶囊化综述 总被引:6,自引:1,他引:5
综述了近年来在超临界溶液快速膨胀过程(RESS和气体抗溶剂法(GAS)基础上拓展出的微胶囊化方法,并设想和展望了超临界萃取和微胶囊化的耦合过程。 相似文献
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阿魏酸和川芎嗪在超临界CO2中溶解度的测定 总被引:2,自引:0,他引:2
采用动态法分别测定了阿魏酸和川芎嗪在超临界CO2中的溶解度.实验结果表明在压力10~35MPa和温度308.15~338.15K范围内,阿魏酸在超临界CO2中的溶解度(摩尔分数)为6.936×10(7~26.527×10(7;在压力10~30MPa和温度318.15~338.15K范围内,川芎嗪在超临界CO2中的溶解度(摩尔分数)为0.010~0.131.阿魏酸在超临界CO2中的溶解度随着压力的增加而增大;温度对阿魏酸溶解度的影响较为复杂,出现了交迭压力行为.而川芎嗪在超临界CO2中的溶解度在实验范围内没有出现交迭压力行为.采用Chrastil方程分别对阿魏酸和川芎嗪在超临界CO2中的溶解度数据进行了关联,其AARD值分别为12.92%和4.23%. 相似文献
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为超临界CO2染色工艺提供必要的基础数据,采用静态循环法在343.2~383.2 K,12~28 Mpa温度压力范围内,测定了分散红343和分散蓝366及其混合物在超临界CO2中的溶解度.实验结果表明,二元体系(分散红343+CO2,分散蓝366+CO2)和三元体系(分散红343+分散蓝366+CO2)中染料的溶解度均随温度和压力的升高而增大;染料分子的极性对其在超临界CO2中的溶解度影响较大;三元体系中两种染料的溶解存在"共溶剂效应"和竞争溶解作用;两种染料在二元和三元体系中的溶解度实验数据用Chrastil方程关联,结果较好. 相似文献
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超临界CO2抗溶剂法制备酶微胶囊过程研究 总被引:1,自引:0,他引:1
研究了以木瓜蛋白酶为芯材,乙基纤维素为膜材的超临界流体抗溶剂(GAS)法制备酶微胶囊过程。在正交实验结果初步表明压力、温度、芯膜比和膜材料浓度依次是GAS法制备微胶囊过程较主要的影响因素基础上,进一步较系统地考察了这些因素对制备的微胶囊的粒径分布、包裹率、释放等性能的影响。 相似文献
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以超临界CO2作为溶剂,采用溢流法研究聚己酸内酯(PCL)在CO2中的溶胀过程和超临界CO2/PCL体系的热力学平衡规律。考察了温度、压力对溶解度的变化趋势,分析加入有机溶剂后对CO2在聚合物中的溶解度的影响,并应用P-T(Patel-Teja)方程作为热力学模型分析和计算溶解规律。结果表明:CO2的溶解度随温度升高而降低,随压力增大而增大,有机溶剂的加入能够进一步提高CO2的溶解度,在相同的温度压力条件下,加入相当于CO2质量的2.26%的二氯甲烷,最多可使溶解度增加28.06%。在温度313.15—353.15 K、压力10—20 MPa范围内,P-T方程能较好地预测CO2在PCL中的溶解度,其相对误差在-12.53%—12.01%。 相似文献
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介绍了超临界二氧化碳抗溶剂结晶过程的基本原理,综述了超临界二氧化碳抗溶剂结晶在制药技术中应用的最新进展,讨论了超临界二氧化碳抗溶剂结晶技术中需要进一步研究的问题和开发的领域. 相似文献
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在温度298—338 K,压力300—700 kPa,吸收剂浓度1—3 mol/L的实验条件范围内,讨论了CO2-吸收剂体系气液二相基本达到平衡时,CO2吸收量与体系温度,压力及吸收剂浓度的关系。根据亨利定律,引入温度及压力相关因子,建立了CO2在单胺溶液中的溶解度模型。模型对CO2在MEA、DETA单胺溶液中的溶解度预测效果较好,与实验值比较,误差在1%以下。引入增强因子β=1.06,并以单胺在混合胺溶液中的摩尔分数为系数,将CO2在单胺溶液中的溶解度叠加获得CO2在MEA+DETA混合溶液中的溶解度模型。模型对MEA+DETA混合胺的预测误差在1%—10%。 相似文献
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The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion. 相似文献
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Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement 总被引:1,自引:0,他引:1
In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably. 相似文献
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Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG), and 3,5-diaminobanzoic acid (DABA), were used as polyelectrolytes in this study. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to monitor the effect of the various kinds of PEG on the changes in morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO4) dopants. The results of DSC and FT-IR indicate the Li+ ions coordinate with the soft and hard segments. Additionally, the crystallinity of the PEG soft segment and the ordered hydrogen-bonded urea carbonyl groups decreased with increasing salt concentration. Impedance spectroscopy (IS) measurements show that the PUU electrolyte with the high phase separation degree has the high ionic conductivity. The hard-segment Tg and the soft-segment Tm influence the conductivity behavior of polyelectrolytes with increasing measurement temperature. 相似文献
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