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采用辛胺疏水改性海藻酸钠合成了具有两亲性的高分子表面活性剂海藻酸辛酰胺(OAAD),并将其与SiO2纳米颗粒协同制备了稳定的Pickering乳液。通过FTIR、1HNMR、表面张力、荧光光谱、动态光散射、接触角测量、光学显微镜分别对OAAD、OAAD/SiO2纳米颗粒水分散体系和Pickering乳状液的性能进行了表征。结果表明,辛胺氨基成功接枝到海藻酸钠(SA)分子链上,OAAD界面张力较SA降低、临界聚集质量浓度为0.60 g/L,表现出良好的两亲性。将OAAD吸附在SiO2纳米颗粒表面形成的水分散体系用于稳定Pickering乳液时,发现随着OAAD质量浓度增加,SiO2纳米颗粒润湿性增加,Zeta电位减少,粒径增加;而乳液的粒径则逐渐减少,稳定性增强,其机理经初步分析为,当一定浓度的OAAD吸附在SiO2纳米颗粒表面,可导致颗粒间絮凝,从而在油水界面形成网络结构式界面膜,有利于提高Pickering乳液的稳定性。 相似文献
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SiO2-MTES-CTAB-Al2O3纳米复合薄膜的制备及性能研究 总被引:2,自引:1,他引:1
以异丙醇铝和正硅酸乙酯为主要原料,采用溶胶-凝胶分步水解法,通过引入有机硅烷甲基三乙氧基硅烷和表面活性剂十六烷基三甲基溴化氨,并用乙二醇甲醚替换铝溶胶中水作为对比,制备了SiO2-MTES-CTAB-Al2O3纳米复合薄膜.通过FT-IR、可见光透射光谱分析、薄膜表面接触角测量及机械性能测试,研究了化学组成、煅烧温度和有无乙二醇甲醚替换对复合薄膜的影响.结果表明:不用乙二醇甲醚替换效果更好,经400 ℃热处理后不同配比复合薄膜在可见光区的透光率均大于85%,且不影响复合薄膜的疏水性,由于铝氧化物颗粒、十六烷基三甲基溴化氨和甲基三乙氧基硅烷的存在,所制备的纳米复合薄膜的硬度及耐摩擦性能均有较大提高,改善了力学性能,从而获得了具有良好的疏水性、透过率及硬质的SiO2-MTES-CTAB-Al2O3纳米复合薄膜. 相似文献
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通过在水介质中添加纳米CdSSe粒子,制备了CdSSe-H2O纳米流体,采用Zeta电位、吸光度并结合沉降照片研究了三种表面活性剂对CdSSe-H2O纳米流体的稳定性影响。结果表明:在0.01wt%CdSSe-H2O纳米流体中,对于三种表面活性剂聚乙二醇2000(PEG2000),十六烷基三甲基溴化铵(CTAB)和十二烷基苯磺酸钠(SDBS),当其浓度分别为0.06%、0.03%和0.05%时体系的分散稳定性最好。针对阴离子表面活性剂在带负电的CdSSe颗粒上的吸附本文提出了表面活性剂离子竞争吸附理论,很好的解释了SDBS对CdSSe-H2O纳米流体的稳定性影响过程。 相似文献
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高分散氧化锆纳米晶体的合成与表征 总被引:5,自引:0,他引:5
用阳离子表面活性剂十六烷基三甲基溴化胺(C19H42BrN)进行自组装,在水热条件下合成了高分散、近似球形、均匀粒径的氧化锆纳米晶体。用热重-差示扫描、Fourier变换红外光谱、X射线衍射、透射电镜、可见-紫外光谱以及N2吸附-脱附等方法对样品进行了表征分析。研究表明:阳离子表面活性剂对形成氧化锆纳米晶体具有明显的导向作用,500℃煅烧的样品其晶粒尺寸约为15nm,分散性能良好,以四方相为主。 相似文献
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为提高低渗油藏的采收率,本文使用聚乙二醇修饰的Si O2纳米颗粒作为添加剂来提高泡沫稳定性,采用溶胶凝胶法合成了4种不同表面修饰量的Si O2纳米颗粒(即聚乙二醇膜),并对纳米颗粒进行了表征,对零电荷点和化学组成等性质进行了测试分析。通过表面活性剂溶液和纳米颗粒的混合得到纳米流体。纳米颗粒在与表面活性剂协同作用下,对气泡的结构强化,以增加其半衰期和耐久性。当表面活性剂浓度高于CMC时,泡沫稳定性达到最大值。纳米流体中纳米颗粒浓度越低,聚合粒径越小。聚乙二醇的用量可以阻止或促进纳米颗粒的聚集,粒径越小,泡沫的稳定性越好。使用α-烯烃磺酸盐表面活性剂和修饰的纳米颗粒生成的泡沫比仅使用表面活性剂的泡沫更稳定。 相似文献
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研究了气相SiO2对环氧树脂E-44的乳化稳定作用。结果表明:气相SiO2的表面性质对环氧树脂E-44的乳化稳定作用有较大影响,未改性的气相SiO2没有乳化作用,阳离子表面活性剂十二烷基三甲基溴化铵(DTAB)、十六烷基三甲基溴化铵(CTAB)改性的气相SiO(2DTAB-SiO2、CTAB-SiO2)能形成较稳定的O/W乳状液,其中用浓度为1×10-3mol/L、接触角为84.1°的CTAB改性气相SiO2得到的乳状液稳定性最好。CTAB-SiO2与环氧树脂专用乳化剂EP-1合用形成的乳状液为W/O/W型多重乳液。 相似文献
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利用三种构型的阳离子表面活性剂〔十六烷基三甲基溴化铵(CTAB)、二亚甲基-1,2-二(N-十二烷基-N,N-二甲基溴化铵) (Gemini 12-2-12)和溴化十烃季胺(Bola)〕分别修饰Fe3O4纳米颗粒,制得Fe3O4@CTAB、Fe3O4@Gemini和Fe3O4@Bola纳米颗粒(三者统称Fe3O4@surfactants)。将其用于水中As(Ⅴ)和As(Ⅲ)的处理。通过XRD、TEM、FTIR和磁性测量系统(VSM)对其形貌进行了表征,同时对As(Ⅴ)和As(Ⅲ)的吸附进行吸附动力学、吸附等温模型拟合和吸附行为研究,并考察了Fe3O4@surfactants的吸附-解吸再生循环性能及结构稳定性。结果表明,Fe3O4@surfactants对As(Ⅴ)的吸附效果均高于As(Ⅲ),吸附符合准二级动力学模型和Langmuir吸附等温模型,且Gemini 12-2-12表面活性剂所修饰的Fe3O4纳米颗粒的吸附容量最大。该吸附过程的吸附驱动力主要来自阳离子表面活性剂分子在固液界面的排列行为、表面活性剂头基与阴离子的静电作用以及尾链与As(Ⅴ)、As(Ⅲ)之间的配位作用。以去除效率较高的As(Ⅴ)进行循环实验,经过5次吸附-解吸循环实验后,Fe3O4@surfactants对As(Ⅴ)的吸附率依然维持在85%左右,且纳米颗粒回收率均在90%以上。 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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组合凹模的应力分析是一个非常复杂的问题,对其进行精确分析是解决模具寿命的关键。本文采用有限元分析软件Ansys对转子的组合凹模进行了分析,为转子组合凹模的优化设计提供了依据。 相似文献
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