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1.
O/W微乳液中聚吡咯超微粒子的制备   总被引:4,自引:0,他引:4  
郭荣  宋根萍 《应用化学》1997,14(4):18-20
选择合适的SDBS/吡咯/H2O三组分O/W微乳液与吡咯单体共存的两相体系,以单体相为单体源,在O/W三组分微乳液中进行了吡咯聚合,所得聚吡咯粒子大小仅为2~3nm,分布较均匀,且具有较好的导电性能.  相似文献   

2.
利用冷冻蚀刻电镜、FT-IR、ESR和NMR方法研究了SDBS/n-C4H9OH/n-C8H18盐水体系中相微乳液微观结构。四种方法均表现随着体系含盐度的增加,中相微乳液微观结构经历了从O/W型到B.C型,再到W/O型的转变。  相似文献   

3.
微乳液结构的研究   总被引:6,自引:1,他引:6  
测定了十二烷基磺酸钠/正丁醇/20%苯乙烯/水体系的相平衡,用冷冻刻蚀、ESR、FT-IR研究了上述体系微乳液的结构,研究表明,苯乙烯含量恒定时,随着体系中水含量增加,电导确定的双连续结构的微乳液经历着从油包水到以连续再到水包油变化,FT-IR测定表明,W/O微乳兴较O/W微乳液的OH伸缩振动和弯曲振动频率有显著减小,说明W/O微乳兴中氢键缔合要比O/W强得多。ESR测定表明O/W微乳液的旋转相关  相似文献   

4.
微乳液增敏作用机理探讨:显色剂在微乳液中的分配系数   总被引:13,自引:0,他引:13  
朱霞石  戚文彬 《分析化学》1995,23(9):989-992
与胶束体系比较,显色剂PNA和CAS在油/水(O/W)微乳液中具有更大的分配系数,这表明O/W微乳液比胶束体系具有更好的增敏作用是因为O/W微乳液对显色剂PAN和CAS具有更好的增溶与富集作用所致。  相似文献   

5.
维生素C对表面活性剂体系相行为的影响   总被引:3,自引:1,他引:2  
维生素C(VC)能提高表面活性剂十六烷基三甲基溴化铵(CTAB)在水中的溶解度,具有助溶作用;且能提高n-C5H11OH在O/W微乳液中的增溶量和水在W/O微乳液中的增溶量,O/W与W/O微乳液区域同时扩大,具有助溶-增溶作用。VC的助溶作用与助溶-增溶作用均具有一定的选择性,只对阳离子表面活性剂CTAB体系有效,VC助溶-增溶作用的机理是同时增加W/O和O/W微乳液的稳定性和层状液晶向双连续结构  相似文献   

6.
聚苯胺的合成及其摩擦学行为的研究   总被引:2,自引:0,他引:2  
选择合适的SDBS/ 苯胺/ 水三组分O/W 微乳液与苯胺单体共存的两相体系,以单体相为单体源,在O/W 三组分微乳液中进行了苯胺聚合,成功地制备出了能够稳定分散于石腊油的聚苯胺微粒。并在四球试验机上研究合成条件、负荷、浓度对其摩擦学行为的影响。结果表明:聚苯胺有一定的减摩抗磨效果  相似文献   

7.
口服聚酯聚醚疫苗蛋白微球的制备研究   总被引:10,自引:0,他引:10  
采用本体聚合法合成不同聚醚含量的聚酯聚醚嵌段共聚物聚 DL 乳酸 聚乙二醇(Poly DL lactide b polyethyleneglycol,PELA).PELA及PLA包裹人血清白蛋白(HSA)微球采用溶剂挥发法双乳液体系(W1/O/W2)制备.微球球形规整,粒径集中在05~50μm.用CBB法检测微球中蛋白含量,蛋白包裹量达25%,包裹效率近80%.从双乳液体系中界面张力角度考察了聚合物囊材的性质、稳定剂的种类及W1/O的稳定性等对微球粒径及蛋白包裹量的影响.微球体外释放结果表明PELA蛋白微球的突释现象不明显,释放速度较为恒定.  相似文献   

8.
SDS/BA/H2O体系的扩散系数与结构特性   总被引:3,自引:1,他引:3  
在无探针条件下,用电化学方法测定了SDS/BA/H2O三组分体系的扩散系数和扩散活化能。结果表明,L1区域由O/W结构微乳液与油、水双连续结构微乳液两个小区域组成,并不是单一的O/W区域。在O/W区域内,微乳液以液滴状态存在,具有较好的扩莠性能和较小的扩散活化能;在BI区域,水与BA同作为连续相与被增溶相存在,缔合体系呈网络结构,扩散性能较低,扩莠活化能较大。  相似文献   

9.
CPDB/正丁醇/正辛烷/水体系溶致液晶的^2HNMR和DSC法研究   总被引:10,自引:1,他引:10  
测定了溴化十六烷基吡啶/正丁醇/正辛烷/水体系的相平衡,在液晶区域选取样品点,用^2HNMR和差示扫描量热法,并与液晶纹理相对照研究了该区域的相结构变化,结果表明,在一定温度下,随着含水量的增加,体系从单一的W/O型微乳液→微乳液和层状液晶共存→层状液晶与六角状液晶共存→层状、六角状与六角状向立方状过渡晶型的三相共存→立方状→O/W型微乳液过度,在组成固定情况下,研究了该体系液晶相结构随温度升高所  相似文献   

10.
郝京诚  尤进茂 《分子催化》1997,11(5):391-393
O/W微乳液催化苯乙烯聚合动力学研究1)郝京诚孙海英汪汉卿2)(中国科学院兰州化学物理研究所兰州730000)尤进茂(曲阜师范大学化学系曲阜273165)关键词微乳液催化苯乙烯聚合动力学分类号O643.13微乳液作为聚合反应介质,催化单体聚合反应研究...  相似文献   

11.
A new rotating membrane emulsification system using a stainless steel membrane with 100 microm laser drilled pores was used to produce oil/water emulsions consisting of 2 wt% Tween 20 as emulsifier, paraffin wax as dispersed oil phase and 0.01-0.25 wt% Carbomer (Carbopol ETD 2050) as stabilizer. The membrane tube, 1 cm in diameter, was rotated inside a stationary glass cylinder, diameter of 3 cm, at a constant speed in the range 50-1500 rpm. The oil phase was introduced inside the membrane tube and permeated through the porous wall moving radially into the continuous phase in the form of individual droplets. Increasing the membrane rotational speed increased the wall shear stress which resulted in a smaller average droplet diameter being produced. For a constant rotational speed, the average droplet diameter increased as the stabilizer content in the continuous phase was lowered. The optimal conditions for producing uniform emulsion droplets were a Carbomer content of 0.1-0.25 wt% and a membrane rotational speed of 350 rpm, under which the average droplet diameter was 105-107 microm and very narrow coefficients of variation of 4.8-4.9%. A model describing the operation is presented and it is concluded that the methodology holds potential as a manufacturing protocol for both coarse and fine droplets and capsules.  相似文献   

12.
Uniformly sized microparticles of poly(d,l-lactic-co-glycolic) (PLGA) acid, with controllable median diameters within the size range 40–140 μm, were successfully prepared by membrane emulsification of an oil phase injected into an aqueous phase, followed by solvent removal. Initially, simple particles were produced as an oil in water emulsion, where dichloromethane (DCM) and PLGA were the oil phase and water with stabiliser was the continuous phase. The oil was injected into the aqueous phase through an array type microporous membrane, which has very regular pores equally spaced apart, and two different pore sizes were used: 20 and 40 μm in diameter. Shear was provided at the membrane surface, causing the drops to detach, by a simple paddle stirrer rotating above the membrane. Further tests involved the production of a primary water in oil emulsion, using a mechanical homogeniser, which was then subsequently injected into a water phase through the microporous membrane to form a water in oil in water emulsion. These tests used a water-soluble model drug (blue dextran) and encapsulation efficiencies of up to 100% were obtained for concentrations of 15% PLGA dissolved in the DCM and injected through a 40 μm membrane.

Solidification of the PLGA particles was followed by removal of the DCM through the surrounding aqueous continuous phase. Different PLGA concentrations, particle size and osmotic pressures were considered in order to find their effect on encapsulation efficiency. Osmotic pressure was varied by changing the salt concentration in the external aqueous phase whilst maintaining a constant internal aqueous phase salt concentration. Osmotic pressure was found to be a significant factor on the resulting particle structure, for the tests conducted at lower PLGA concentrations (10% and 5% PLGA). The PLGA concentration and particle size distribution influence the time to complete the solidification stage and a slow solidification, formed by stirring gently overnight, provided the most monosized particles and highest encapsulation efficiency.  相似文献   


13.
This study addresses problems encountered with an emulsion/membrane bioreactor. In this reactor, enzyme- (lipase) catalyzed hydrolysis in an emulsion was combined with two in-line separation steps. One is carried out with a hydrophilic membrane, to separate the water phase, the other with a hydrophobic membrane, to separate the oil phase. In the absence of enzyme, sunflower oil/water emulsions with an oil fraction between 0.3 and 0.7 could be separated with both membranes operating simultaneously. However, two problems arose with emulsions containing lipase. First, the flux through both the hydrophilic and the hydrophobic membranes decreased with exposure to the enzyme. Second, the hydrophobic membrane showed a loss of selectivity demonstrated by permeation of both the oil phase and the water phase through the hydrophobic membrane at low transmembrane pressure. These phenomena can be explained by protein (i.e. lipase) adsorption to the polymer surface within the pores of the membrane. It was proven that lipase was present at the hydrophilic membrane and that this, in part, explains the flux decrease of the hydrophilic membrane. To prevent the observed loss of selectivity with exposure to protein, the hydrophobic polypropylene membrane (Enka) was modified with block copolymers of propylene oxide (PO) and ethylene oxide (EO). These block copolymers act as a steric hindrance for proteins that come near the surface. The modification was successful: After 10 days of continuous operation the minimum transmembrane pressure at which water could permeate through an F 108-modified membrane was 0.5 bar, the same value as that observed in the beginning of the experiment. This indicates that loss of selectivity due to protein adsorption is prevented by the modification of the membrane.  相似文献   

14.
采用相反转方法制备了丙烯酸(AA)接枝的超亲水-水下超疏油聚偏氟乙烯膜(PVDF-g-PAA),通过加入一定量的聚乙烯吡咯烷酮获得可用于油水分离的多孔聚偏氟乙烯膜.多孔聚偏氟乙烯膜具有较好的抗油污染性能及较高的力学强度,可以快速高效地分离油水混合体系和乳化油水体系,分离性质稳定,多次使用后对油水混合物的分离效率在98%以上,对油水乳化液的分离效率在91%以上,可广泛应用于油水混合体系和乳化油水体系的油水分离.  相似文献   

15.
The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustained and rhythmic oscillation was observed. To a certain extent, the features of the oscillation (e.g. induction time, frequency, life time and orientation of the pulse pikes) strongly depend on the property of surfactant, dissolved in octanol. The mechanism may be explained by the formation and destruction of dual-ion surfactant membrane accompanying with emulsification at the interface and considering the coupling effect of diffusion and associated reaction in the vicinity of the interface.  相似文献   

16.
报道了谷氨酸在乳状液膜体系中的迁移行为,采用失水山梨醇单油酸酯(span80)-乙基己基琥珀酸酯磺酸钠(AOT)为表面活性剂,对氨基苯磺酸(APS)为载体,煤油为膜溶剂,氯化钾为内相试剂.讨论了制乳时间和乳液与外相混合时间、表面活性剂和流动载体浓度、内相试剂浓度、水乳比和油内比对分离效果的影响.确定了最佳分离条件为制乳...  相似文献   

17.
乳状液膜法分离水中的铬   总被引:3,自引:0,他引:3  
乳状液膜法由于其独特的物理化学性质,已广泛用于金属离子的萃取分离[1~3]。本文以span80-煤油-NaOH液膜体系分离水中铬。不加流动载体,利用内、外相中被分离物的浓度梯度实现物质迁移。当Cr2O2-7进入内相时,与内相的NaOH发生反应,在内相高浓度的NaOH存在下,可保持Cr2O2-7在液膜两侧有最大的浓度梯度,促使Cr2O2-7的迁移,实现Cr2O2-7与外相溶液的分离。1 实验部分1 1 仪器与试剂D40-1型电动搅拌器(杭州仪表电机厂),78-1型磁力加热搅拌器(江苏金坛新一佳仪器厂),721型分光光度计(上海第三分析仪器厂)。铬标准溶液(100ml/L):准…  相似文献   

18.
镍在乳状液膜体系中的迁移行为   总被引:3,自引:0,他引:3  
研究了镍在乳状液膜分离体系中的迁移行为。在此分离体系中,以煤油作为膜溶剂,span80为表面活性剂,磷酸三丁酯(TBP)为载体。详细讨论了制乳时间和混合时间、span80和TBP浓度、乳水比和油内比、内相NH。和外相HCl的浓度对镍迁移率的影响,确立了最佳分离条件。  相似文献   

19.
Recently, there has been an increasing interest in the breakage of water-in-oil (W/O) emulsions by the freeze/thaw method. Most of the previous works focused on the phase transition of the water droplet phase. This paper emphasizes the effect of continuous oil phase transition. A series of oils with different freezing points were used as oil phases to produce model emulsions, which were then frozen and thawed. The emulsion whose oil phase froze before the water droplet phase did (OFBW) on cooling was readily demulsified with a dewatering ratio as high as over 80%, but the emulsion whose oil phase did not freeze when the water droplet phase did (NOFBW) was relatively hard to break. The difference in demulsification performance between them resulted from the distinction between their demulsification mechanisms via the analyses of the emulsion stability, emulsion crystallization/melting behaviors, oil phase physical properties, and wettability of the frozen oil phase, etc. For the OFBW emulsion, the first-frozen oil phase was ruptured by the volume expansion of the subsequently frozen droplet phase, and meanwhile, some liquid droplet phase was drawn into the fine gaps/crevices of the frozen oil phase to bridge droplets, which were considered to be essential to the emulsion breakage, whereas for the NOFBW emulsion, the demulsification was attributed to the collision mechanism proposed in our previous work. The findings may provide some criteria for selecting a proper oil phase in the emulsion liquid membrane (ELM) process and then offer an alternative approach to recycle the oil phase for continuous operation. This work may also be useful for emulsion stability against temperature cycling.  相似文献   

20.
近年来膜分离技术在环境治理方面得到广泛应用。本文研究了铜在span80-TBP(磷酸三丁酯)-煤油-NH3液膜分离体系中的迁移行为。用TBP作为载体,在溶液中迁移时,在外相与膜相界面上形成中性络合物后穿过膜相,在膜相与内相界面上络合物再与NH3反应,生成铜氨络离子,释放出来的TBP又返回膜相。  相似文献   

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