共查询到19条相似文献,搜索用时 187 毫秒
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采用Stokes落球模型研究了两相密度差对油/水分散体系悬浮稳定性的影响规律,考察了水相粘度及水相界面张力对油/水分散体系分散稳定性的影响。结果表明:复色多相分散体系的悬浮稳定性主要由两相密度差决定,当两相密度差降至0.5kg/m3时,可以制得悬浮稳定性很好的复色多相分散体系。水相粘度增大,悬浮稳定性提高。水相界面张力对丙烯酸酯-聚氨酯油相形成的分散体系影响较大,当其界面张力大于69.5×10-3N/m时,分散稳定性好。只要粒子间不易相互融结,形成的复色多相分散体系便不发生渗色现象。 相似文献
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氧化锆增韧堇青石陶瓷的研究 总被引:3,自引:1,他引:3
添加分散的氧化锆对多晶体堇青石进行了增强和增韧。含10%(按质量计,下同)ZrO2的氧化锆增韧堇青石陶瓷(ZTCC)的抗弯强度(130MPa)较1400℃,6h制备的人工合成高纯多晶堇青石的(74.3MPa)有明显提高。含有5%ZrO2和1%CaO二元弥散相粒子的ZTCC的断裂韧性增大至2.83MPa·m^1/2。当加入15%Y-TZP,样品的抗弯强度和断裂韧性分别高达188MPa和3.2MPa· 相似文献
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多级搅拌塔气液液系统的轴向混合 总被引:1,自引:0,他引:1
本文在内径为54mm,级数为16的多级搅拌塔中,研究了空气-水-煤油系统的轴向混合性质。讨论了搅拌转速、水相流速、有机相流速及气相流速对液体连续相和分散相轴向混合的影响。得到了操作范围内描述塔内轴向扩散系数的关联式。对连续水相:Ec=0.745·Ns0.530·ug0.459·uc0.691·ud0.319对分散有机相:Ed=21.92·Ns0.465·ug0.898·uc0.258·ud0.762 相似文献
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综述了多相操作均相催化技术的研究进展,分成水相-有机相、有机相-有机相、全氟相溶剂对、超临界流体相、非水离子液体溶剂相和可溶态聚合物相等组成的两相操作均相催化体系。重点评述了水相/有机相两相体系。水相-有机相两相体系率先使得多相操作均相催化技术获得突破,并且取得工业化应用成就,也是目前最受工业界和学术界关注的领域。 相似文献
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聚氨酯脲-乙烯基聚合物复合水分散液 总被引:7,自引:0,他引:7
以蓖麻油、二官能度聚醚多元醇(GE 210)、苯乙烯和丙烯酸丁酯等原料合成了聚氨酯脲-乙烯基聚合物(PUA)复合水分散液,并研究了这类水分散体系的粒子形态、流变性能以及稳定性。结果表明,分别由蓖麻油以及蓖麻油与GE 210质量比为1/l合成的PUA分散液中的分散相呈现出较好的核壳结构,分散液的粘度较小,接近于牛顿流体,且体系的电位绝对值和临界聚沉浓度较大。由GE 210合成的PUA复合水分散液中未观察到规则的分散粒子,分散液的粘度较大,表现为假塑性流体,且对电解质较敏感。 相似文献
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将碱法制浆黑液与稠油混合,可明显降低稠油的粘度.用均匀设计法设计试验,讨论了黑液浓度、稠油酸值、水油比(体积)、温度及水的矿化度对稠油降粘作用的影响.结果表明,黑液浓度为5%~15%,酸值为3~4.5mg/g(KOH/油)时,体系粘度最低,在试验范围内,水油比越大,温度越高,矿化度越小体系的粘度越低. 相似文献
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负离子型聚氨酯离聚体水分散过程的相反转 总被引:1,自引:0,他引:1
用异佛尔酮二异氰酸酯、聚己二酸新戊二醇酯和二羟甲基丙酸(DMPA)合成了负离子型聚氨酯离聚体.研究了该类离聚体在水分散过程中的相反转变化,讨论了DMPA质量分数和水分散温度对相反转过程的影响。结果表明,DMPA质量分数增加或水分散温度提高,可使相反转所需的时间缩短,分散液粒子粒径变小,粒径分布更均匀,黏度增大。水分散温度的作用较DMPA更为明显。差示扫描量热分析表明,水分散过程破坏了亲水性硬链段的有序性。傅里叶变换红外光谱分析表明,聚氨酯水分散液用乙二胺扩链后.脲羰基的氢键化程度随DMPA质量分数的增加、水分散温度的提高而提高。 相似文献
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剪切增稠液体是指其表观粘度随剪切速率增加而变大的一类流体。工业生产中,剪切增稠的出现会阻碍输送管道,破坏生产设备。针对这种情况,人们对如何降低流体粘度造成的不利影响进行了大量研究。另一方面,剪切增稠液体是“液体防弹材料”的关键组成部分,并且在减震、控制方面也具有可观的应用潜力。该文采用原生粒径为50 nm 的SiO2和80~100 nm 的 CaCO3分别作为分散相,聚乙二醇(PEG)200为分散介质,采用超声分散法制备得到不同固含量的剪切增稠液。并通过纳米粒度仪和扫描电镜对分散相粒子团聚情况进行分析;通过应力控制流变仪分别对 SiO2/PEG200和 CaCO3/PEG200悬浮分散体系的稳态流变性能进行分析。结果表明,两种体系试样在测试中均出现剪切增稠现象,并且分散相质量分数越高,剪切增稠效果越明显;而高质量分数的 SiO2/PEG200体系的粘度变化范围更大,增稠现象更为明显。 相似文献
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汽液液三相精馏总板效率的研究 总被引:7,自引:2,他引:5
在Oldershaw精馏塔内,对汽液液三相精馏筛型塔板上的传质特性进行测试,研究了泡沫工况下,汽速、液汽比等操作条件,表面张力梯度、界面张力、乳化液分散粘度等物系性质,以及油水体积比等多种参数对总板效率的影响、对测试数据进行关联,获得了适用于泡沫工况下汽液液三相精馏过程的总板效率估算式,此关联式对设备设计及操作优化有一定的参考价值. 相似文献
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利用纳米Fe3O4作为稳定剂和乳化剂来制备Pickering型ASA(alkenyl succinic anhydride) 施胶乳液,并研究了固体颗粒浓度、油水比、水分散相pH对乳液类型、稳定性、形态及施胶性能的影响。结果表明,纳米Fe3O4能够乳化制备均一稳定的Pickering型ASA乳液。乳液在室温下静置稳定,析出油相体积分数随固体颗粒用量的增加而增大,随油水比的增大而减小。油水比为2:1,水分散相浓度为0.1%(质量分数)时制备的ASA乳液稳定性最佳。固体颗粒部分吸附在油/水界面处,部分分散在分散相中,随分散相中固体颗粒浓度的增加,乳液稳定性变差。乳液静置分层之前,ASA发生部分水解。在放置1 h后用于纸页浆内施胶,随ASA乳液用量的增加,纸页表面接触角逐渐增大,且纸页表面粗糙度下降。在ASA的添加量为1.0%(质量分数)时,纸页表面接触角达到93.5°,纸页表面粗糙度为15.924 μm。 相似文献
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疏水纳米颗粒分散于有机体系中形成的纳米分散体,具有独特的理化性质和重要的应用价值。其中,纳米颗粒的单分散性、均匀性和稳定性是决定纳米分散体性能的关键。以CuO纳米分散体作为纳米流体和复合薄膜前体这一典型体系为研究对象,通过设计平板型微通道实现了CuO纳米分散体制备过程中的液滴聚并和改性CuO纳米颗粒的原位分散。制备了颗粒体积分数达2%、平均粒径约30 nm的CuO-基础油纳米流体,该纳米流体具有良好的稳定性和达到0.184 W·m-1·K-1的较高热导率;制备的CuO-PDMS(聚二甲基硅氧烷)复合薄膜具有较强的抗菌性能和颗粒复合层稳定性。通过系统性实验研究,证明了原位分散方法在强化改性颗粒高效分散中的重要作用,确定了颗粒性能及分散行为对分散体性能的影响规律。 相似文献
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《Progress in Organic Coatings》2001,42(3-4):188-193
Thickening of lattices of styrene–acrylic copolymers containing a small amount of acrylic acid and various amounts of 2-hydroxyethyl methacrylate (HEMA) with alkali-swellable dispersion of crosslinked ethyl acrylate/methacrylic acid copolymer has been studied using capillary viscometry and dynamic and steady shear measurements. The higher the amount of HEMA incorporated into the latex copolymers, the stronger the thickening effect is. A comparison of flow behavior of thickened systems with those of neat lattices confirmed a significant influence of the effective volume fraction of alkalinized swollen latex particles on the thickening process. Under these conditions, to obtain the same rheological properties, the necessary amount of thickener was lower for the latex copolymers with higher amounts of HEMA because a part of the thickener volume fraction was replaced by an increased volume fraction of swollen latex particles. These findings indicate weakly interacting dispersion systems without strong compression of particle domains. 相似文献
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Jonathan McCulfor Paul Himes Mark R. Anklam 《American Institute of Chemical Engineers》2011,57(9):2334-2340
The effect of water on the flow behavior of glass microspheres dispersed in mineral oil was investigated for various levels of water, particle volume fractions, and particle sizes. The addition of small amounts of water leads to large increases in viscosity due to the formation of water bridges between particles that give rise to capillary forces between the particles. The capillary forces between the particles also make the flow profile highly shear‐thinning across the range of particle volume fractions that were studied (0.10 to 0.25). The presence of water leads to a significant effect of particle size, and the viscosity of dispersion goes through a maximum as the amount of water is increased. Two hydrophobic surfactants, Span 80 and Arquad 2HT, were found to reduce the viscosity of the dispersions with added water, but the mechanism and extent of viscosity reduction differed. © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
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Dongming QI Xiaoli ZHAO Zhijie CHEN Peng HUANG Jun CAO 《Frontiers of Chemical Science and Engineering》2012,6(4):395
A novel phenolic rigid organic filler (named KD) with a high melting point was dispersed in an isotactic polypropylene (iPP) matrix by solution-mixing and/or melt-mixing. A series of KD/iPP blends was prepared with or without addition of maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Influences of MAPP and mixing methods on the filler dispersion were studied using polaried optical microscope (POM), scanning electron microscope (SEM) and tensile test. The filler particles are always inclined to form large irregular aggregates in the iPP matrix due to their significant differences in polarity and solubility in solvent. However, an iPP/MAPP/KD (PMK) blend containing filler particles with a quasi-spherical shape (~97.8 nm in diameter) and narrow particle size distribution (polydispersity index= 1.076) was successfully prepared by incorporating MAPP to reduce the interfacial tension and surface free energy between the dispersion phase and the continuous phase, and adopting a spray-drying method after solution-mixing to suppress the increase of the size of the dispersed phase during the removal of solvent. 相似文献