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《中国粉体技术》2016,(6)
采用3种硅烷偶联剂双-[γ-(三乙氧基硅)丙基]四硫化物(Si69)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)、乙基三甲氧基硅烷(11-100)对沉淀法白炭黑粉体进行有机湿法改性。借助傅里叶红外光谱、接触角仪、纳米粒度及Zeta电位仪、扫描电镜等检测手段对白炭黑改性前后的结构及性能进行表征,研究考察3种不同偶联剂对沉淀法白炭黑的疏水性及分散性的影响。结果表明:3种不同硅烷偶联剂都已成功接枝到白炭黑表面,其中Si69改性的白炭黑剩余羟基数与未改性白炭黑表面羟基数的比值最小,为34.23%;经偶联剂改性后的白炭黑,团聚现象减弱,粒径分布变窄,分散性得到改善,疏水性大小依次为Si69-Si O_2KH570-Si O_211-100-Si O_2;综合对比3种偶联剂的改性效果,Si69的改性效果最好。 相似文献
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用KH550硅烷偶联剂和聚电解质型表面活性剂聚乙烯亚胺(PEI)分别对金刚石进行表面改性,研究了KH550和PEI对金刚石表面电性、金刚石在聚酰胺酰亚胺树脂液中的悬浮性及与树脂结合性的影响.结果表明:改性后金刚石表面的电性能发生显著变化,在酸性条件下,zeta电位绝对值明显提高,颗粒间的静电斥力增强,改善了金刚石在树脂液中的悬浮稳定性;改善了树脂对金刚石表面润湿性及其界面结合性,提高了线锯的切割性能;KH550对金刚石的改性效果优于PEI的改性效果. 相似文献
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以正硅酸乙酯为原料,采用溶胶-凝胶法及种子生长法制备出不同粒径(290nm、960nm、1.3μm和1.9μm)的SiO2胶体颗粒,并研究了KH570对SiO2胶体颗粒表面疏水性的影响。粒度分析、扫描电镜及X射线衍射分析结果表明,产物均为球形单分散SiO2胶体颗粒;而接触角、表面羟基数和亲油化度等测试结果显示,KH570浓度和改性时间对SiO2胶体表面性质影响显著,且丙酮作为助剂改性效果比水更好,最佳条件是以丙酮为助剂,使用1%KH570回流处理6h。此外,在存在KH570时进行溶胶-凝胶过程可一步制备出直径为1.9μm的单分散SiO2疏水颗粒。 相似文献
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采用硅烷偶联剂KH-570对羟基磷灰石粉体进行表面修饰,使羟基磷灰石在聚合物介质中有较好的相容性和分散稳定性。采用红外光谱、热重、差热、激光粒度、Zeta电位和X射线衍射等方法对表面修饰前后的羟基磷灰石进行表征分析。结果表明,KH-570硅烷偶联剂结合在羟基磷灰石表面,并未对其晶体产生明显影响;羟基磷灰石经修饰后在水溶液中的Zeta电位绝对值增加,分散稳定性提高,粒子团聚程度降低,纳米级颗粒尺寸从272.8nm减小到166nm,Cd2+吸附性能随增重率的增加而降低。 相似文献
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为进一步改善超细CaCO3的表面活性,利用γ-氨基丙基三乙氧基硅烷偶联剂(KH-550)对超细CaCO3进行表面改性,采用密炼工艺制备了超细CaCO3/热塑性丁苯橡胶(SBS)复合材料.通过红外光谱(FT-IR)、热重分析(TGA)、接触角测定仪(CAMI)和粒径分析等研究了改性前后超细CaCO3的结构变化,采用橡胶加工分析仪(RPA)和扫描电子显微镜(SEM)等对改性前后超细CaCO3的复合材料的力学性能和微观形貌进行了测试分析.结果表明:硅烷偶联剂KH-550与超细CaCO3粉体间能形成化学结合,修饰后的超细Ca-CO3能有效阻止颗粒间团聚,并均匀分散在橡胶胶体中,与胶体间形成物理和化学交联结构;改性后超细Ca-CO3在SBS体系中能形成网状结构,材料力学性能明显提高;当活化超细CaCO3的质量分数为20%时,能获得性能优异的复合材料. 相似文献
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纳米ATO粉体的表面改性研究 总被引:1,自引:0,他引:1
采用偶联剂对纳米ATO(氧化锡锑)粉体进行表面改性,综合考察了偶联剂的品种与用量、反应时间及反应温度对表面改性效果的影响,从而确定最佳表面改性条件.利用红外光谱(FTIR)、热重分析(TGA)以及光吸收率等表征手段来研究表面改性的效果及分散状况.结果表明,纳米ATO粉体表面改性的最佳条件为:选用硅烷偶联剂KH570,添加量为2份,反应水浴温度为80℃,反应5h. 相似文献
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目的研究硅烷偶联剂KH550含量对木粉/P34HB复合包装材料性能的影响。采用KH550改性木粉,提高与聚(3-羟基丁酸酯-4-羟基丁酸酯)(P34HB)的结合强度,改善复合材料的力学性能和界面相容性。方法以KH550为改性剂,木粉和P34HB为原料,利用共混热压工艺制备改性木粉/P34HB复合材料;通过对复合材料的形貌进行观察,以及傅里叶变换红外光谱(FTIR)、热重分析(TGA)和力学性能分析,研究KH550质量分数不同时对复合材料界面相容性、力学性能和热性能的影响。结果添加KH550后,复合材料的的界面相容性得到改善;FTIR分析表明,KH550已经成功接枝到木粉中;适量的KH550提高了复合材料的热稳定性;复合材料的储能模量增加;复合材料的力学性能也有所提高。此外还得到了最佳的KH550添加量,即质量分数为0.5%。结论 KH550不仅使得木粉与P34HB的相容性得到改善,同时也增强了复合包装材料的力学性能和热性能。 相似文献
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Haoran Chen Hao Zhu Zhichao Huang Wenhui Rong Kai Wu 《Advanced materials (Deerfield Beach, Fla.)》2019,31(50)
A heterogeneous catalytic process involves many surface elementary steps that affect the overall catalytic performance in one way or another. In general, a high‐performance heterogeneous catalyst should meet the main criteria: excellent catalytic activity and high selectivity toward target products. Using surface science techniques, the two‐sidedness of the surface reaction mediations can be explored, from the perspectives of the surface and the molecule manipulations. The surface manipulation refers to a reaction that is mediated by composition and structure of the substrate as well as surface species, while the molecular manipulation relates to a reaction that is mediated by the reacting molecule via the precursor selection, environmental control, or external excitation. The best catalytic system should consist of the most efficient catalyst and the best suitable reacting molecule, in addition to its economic benefit and environmental amity. Recent research progress in surface reaction mediation is outlined, and its two‐sidedness is governed by the Arrhenius equation. This should shed new light on the connection between basic theory and surface reaction mediation strategies. To conclude, challenges and possible opportunities are elaborated for efficient surface reaction mediations. 相似文献
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从实测大生产物料的动态表面张力和静态表面张力数据,用表面活性剂在涂布液的扩散和在新表面吸附过程,分析涂布过程出现的余布弊病,并提出解决的办法。 相似文献
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Heterogenous reactions under transport control can be modelled in terms of a film of reaction products covering the reaction surface. Such a surface defines a unique direction in space which may be used to classify transport processes as transverse or longitudinal. Since crossed-gradient transport occurs, a Péclet number Pe is introduced, representing the ratio of the velocities characterizing transverse and longitudinal transport, with transverse transport being by film diffusion of some reacting species and longitudinal transport corresponding to film flow as with wetting processes. If the influence of viscosity is taken into account in terms of a Schmidt number Sc, the long-wave approximation for the evolution of thin films on reaction surfaces is shown to be equivalent to a distinguished limit Pe 0, Sc , while keeping 1/
. The long-wave approximation is derived by an application of the method of strained variables which leads to a film equation for the spatio-temporal evolution of the film thickness h which represents the crucial element for a complete solution of the thermo-hydrodynamics of the layer. Since film generation due to chemical reaction and film removal due to evaporation may compensate for certain thicknesses h, surface phases are found to occur which correspond to stationary layers of uniform thickness. The evolution of the surface layer is shown to be a generalized reaction-diffusion process, with surface waves representing dynamical transitions between surface phases. 相似文献
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基于球面三角网格逼近的等距曲面逼近算法 总被引:2,自引:0,他引:2
给出了一种基于球面三角网格逼近的等距曲面逼近新算法。利用三角网格逼近基球面,然后计算此三角网格按中心沿在曲面扫凉而成空间区域的边界作为等距曲面的逼近。该算法计算简单,方便地解决了整体误差问题,而且所得到的逼近曲面是与原曲面同次数的NURBS曲面。 相似文献