纳米粉体在聚合物熔体中的分散理论

综述了纳米粉体在聚合物熔体中的分散理论,包括纳米粉体聚集体中聚集力的模型及影响因素、纳米粉体聚集体在流场中所受外力的模型及影响因素,介绍了纳米粉体聚集体分散的破裂机理和剥蚀机理,评述了各个模型及相关机理的优点和局限性,建议要将更多的影响因素如表面能等引入模型中,要考虑破裂分散与剥蚀分散之间的竞争关系,注重分散结构在加工过程中的演变过程,以强化分散模型的动力学特征。     

微波辅助草酸盐沉淀法合成钛酸钡纳米粉体的分散性研究

本文采用微波辅助草酸盐沉淀法在微波条件为80℃,30 min和煅烧条件为700℃,1h的工艺参数下制备了四方相钛酸钡纳米粉体.用X射线衍射仪和透射电子显微镜研究了分散剂种类及用量对钛酸钡纳米粉体的相组成与微观形貌的影响,探讨了其分散机理.结果表明,有着不同分散机理的阳离子分散剂三乙醇胺和非离子分散剂OP-10都能使纳米粉体具有良好的分散效果.当分散剂添加量为3％ ～5％时,分散效果最明显.     

非水介质中纳米ZnO分散体系的制备

在纳米粉体的研究和应用过程中,如何得到高度分散的纳米粉体是一难题。采用均匀沉淀法合成纳米ZnO,讨论了其在非水介质中的分散条件及其影响因素。通过阴离子表面活性剂包覆纳米ZnO,可以得到其在非水介质中的分散体系,经IR和TEM检测,表明包覆层均匀,颗粒粒径介于30－80nm。     

无机纳米颜料在造纸涂料中的应用

纳米材料因其四大效应已引起了广泛的关注，纳米粉体的团聚成为其工业化生产应用的瓶颈。介绍了纳米粉体的团聚、分散机理及其分散方法。阐述了无机纳米颜料在造纸涂料中的应用状况，并对其存在的问题和应用潜力作了探讨。     

复合化学镀(Ni-P)-Si3N4纳米微粒复合镀层研究——表面活性剂的影响

采用化学镀方法制备(Ni-P)-Si_3N_4纳米微粒复合镀层,研究了不同类型表面活性剂及分散方式对镀液中纳米粉体分散稳定性的影响。结果表明:采用超声波加阴离子表面活性剂分散纳米粉体,可提高镀液中纳米颗粒的分散和稳定性;提高了镀层的硬度,使复合镀层的耐蚀性比Ni-P合金镀层提高20%～50%,耐磨性提高将近4倍。     

功能性复合材料用微纳米复合粉体生产

正一、成果简介新材料产业的发展带动了纳米粉体技术的发展,合理分散和使用纳米粉体已经成为制约该技术应用的瓶颈。各类纳米粉体根据用途而进行二次加工处理,制备用户方便使用的"功能性微纳米复合粉     

水热法制备锑掺杂SnO2纳米粉体的研究

用SnCl4·5H2O和SbCl3作前驱体用水热法合成了Sb掺杂的SnO2纳米粉体,并用DTA,XRD,TEM,FT-IR方法研究了纳米粉体的特性.XRD结果显示纳米粉体的尺寸为4 nm;随热处理温度升高,晶粒长大,表面积减少;TEM结果证实纳米颗粒是呈单分散状态.     

剪切力和pH值的变化对SiC纳米粉体分散行为的影响

在采用超声波和分散剂的基础上,通过控制剪切力和pH值的分散方法,对SiC纳米粉体在水介质中的分散行为进行了研究.结果表明:经过处理后的SiC纳米粉体悬浮液的平均粒度可达51.7 nm左右,稳定时间从几十分钟提高到一个月以上.     

纳米材料在水性涂料中的应用

综述了目前国内外纳米粉体在水性涂料中的分散技术，介绍了对纳米粉体进行修饰和表面包覆改性方面的研究情况，分析了目前研究中存在的问题及发展趋势。     

功能性复合材料用微纳米复合粉体生产

正一、成果简介新材料产业的发展带动了纳米粉体技术的发展,如何合理分散和使用纳米粉体已经成为制约该技术应用的瓶颈。因此,各类纳米粉体根据用途而进行二次加工处理,制备用户方便使用的"功能性微纳米复合粉体材料"也就逐渐形成了市场。该技术的特点是:借助微米级母粒子与纳米级     

纳米粒子的分散机理、方法及应用进展

分析了纳米粒子团聚机理,并介绍了纳米粒子分散理论、方法,包括机械法和表面改性法,尤其详细地介绍了表面改性的方法,如：无机物改性纳米粒子表面、有机物改性纳米粒子表面、有机．无机复合改性纳米粒子表面,并介绍了相应的应用成果。     

Fe_3O_4/PANI抗氧化水基磁流体的制备与表征

在无氮气保护条件下,用化学共沉淀法制备了四氧化三铁(Fe3O4)纳米颗粒,并通过表面原位合成法将颗粒用聚苯胺(PANI)包裹,由此获得兼具磁性和导电性能的纳米四氧化三铁/聚苯胺(Fe3O4/PANI)材料。作者称其为Fe3O4/PANI抗氧化水基磁流体。透射电子显微镜(TEM)分析表明,该法制备的Fe3O4/PANI复合粒子的粒径在30~50 nm,其分散性能比包裹前的Fe3O4粒子明显改善。红外光谱(FTIR)和X射线衍射(XRD)测试结果发现,Fe3O4粒子及Fe3O4/PANI复合粒子具有不同的物态和晶相结构。对纳米复合粒子的抗氧化性能和磁性能的检测证实,原位合成的Fe3O4/PANI复合粒子不仅能有效防止在空气中被氧化,还可在磁场环境中实现快速富集、定位,为Fe3O4/PANI纳米复合粒子在生物医学领域的应用提供了可能。     

沉淀法制备纳米氧化铟粉末

为了开发适合工业化大规模生产超细且分散性好的In<,2>O<,3>粉体的方法,作者以金属铟、盐酸、氨水为原料,对化学沉淀法制备纳米氧化铟粉末的过程进行了研究.通过严格控制实验条件制备出了单相、分散性好、晶粒尺寸约为30nm,粒度分布范围窄的立方晶系纳米In<,2>O<,3>球形粉末.     

Preparation of barium sulfate particles using filtration dispersion precipitation method in O/W system

In this paper, a new method to synthesize BaSO₄ nano-particles in O/W system with filtration dispersion technology was developed. The nano-particles of barium sulfate were prepared using a type of filtration dispersion device with a plate porous disc as a dispersion medium. Working systems of barium chloride aqueous solution/30% TBP (in kerosene) with sulfuric acid were applied. The influence of the reactant concentration and the operation conditions were investigated. The morphology of the particles was observed by SEM, and the particle-size distributions were measured. The nano-particles prepared in O/W system were compared with those prepared by dispersing aqueous barium chloride solution into aqueous sodium sulfate solution with the same filtration dispersion device. The results showed that mono-dispersed BaSO₄ particles can be prepared using the filtration dispersion method in O/W systems. The surfaces of all the particles were smooth. The mean diameter of the particles was in the 100-400 nm range and decreased with the increase of flux of the two phases. The ratio of the two phases greatly affects the morphology of particles because of the excess concentration of [SO₄²⁻]. The particle size was also much smaller when the mixed two feeds were aqueous solutions.     

纳米Cr3C2颗粒在Co-Ni复合镀液中的分散稳定性研究

采用超声破碎法制备了含纳米Cr3C2颗粒的钴镍镀液,研究了未加分散剂,以非离子型高分子分散剂改性和以阴离子分散剂改性三种情况下的镀液性能。通过激光粒度仪、镀层中颗粒复合量等测试方法对纳米Cr3C2颗粒钴镍镀液的稳定性进行了表征。结果表明,含纳米Cr3C2颗粒钴镍镀液通过阿拉伯树胶高分子型分散剂改性后,镀液的稳定性最佳,当阿拉伯树胶添加量为0.3 g/L,超声时间为0.5 h时,所得纳米Cr3C2颗粒钴镍镀液的稳定性最好。     

Tensile Strength of Joints Bonded With a Nano-particle-Reinforced Adhesive

In order to improve the tensile lap shear strength of adhesively bonded joints, nano-particles were dispersed in the adhesive using a 3-roll mill. The dispersion states of nano-particles in the epoxy adhesive were observed with TEM (Transmission Electron Microscopy) with respect to the mixing conditions, and the effect of nano-particles on the mechanical properties of the adhesive was measured with respect to dispersion state and weight content of nano-particles. Also the static tensile load capability of the adhesively bonded double lap joints composed of uni-directional glass/epoxy composite and nano-particle-reinforced epoxy adhesive was investigated to assess the effect of nano-particles on the lap shear strength of the joint. From the experimental and FE analysis results, it was found that the nano-particles in the adhesive improved the mechanical properties of the adhesive. Also the increased failure strain and the reduced CTE (coefficient of thermal expansion) of the nano-particle-reinforced adhesive improved the lap shear strength of adhesively bonded joints.     

高分子聚合物包覆无机纳米粒子的研究进展

简单介绍了非液滴内成核法、液滴内成核法包覆无机纳米粒子的原理,重点讨论了乳液聚合法、无皂乳液聚合法、分散聚合法、悬浮聚合法、细乳液聚合法包覆无机纳米粒子的优缺点。针对包覆过程中产生的独立聚合物粒子、独立无机粒子,提出采用引发剂吸附在无机颗粒表面、采用反应性乳化剂和偶联剂处理无机粒子并控制单体用量;针对包覆多个无机粒子,提出采用聚合前超声空化技术。     

纳米颗粒分散模型及其在纳米CaCO3悬浮液制备中的应用

文章以简单立方体堆积模型作为纳米颗粒在分散体系中的分散模型,分析了纳米颗粒的体积百分含量和质量百分含量与纳米颗粒的颗粒间距离和粒径的关系,制备了1 wt%,2 wt%,10 wt%的纳米CaCO3悬浮液。透射电镜显示纳米CaCO3分散均匀,未出现团聚。模型及实验结果表明颗粒间距离为粒径的2-3倍时,纳米颗粒分散均匀并保持稳定。对于平均粒径为40 nm的纳米CaCO3,悬浮液的最佳质量百分含量为10%左右。     

Effect of Pt nano-particle size on the microstructure of PEM fuel cell catalyst layers: Insights from molecular dynamics simulations

The effect of Pt nano-particles size on the microstructure of catalyst layers in a Polymer Electrolyte Fuel Cell is investigated by means of molecular dynamics simulations. The catalyst layer model includes carbon-supported platinum, perfluorosulfonate ionomer (PFSI), hydronium ions and water molecules. Three different Pt nano-particle sizes, i.e. 1, 2 and 3 nm, are studied, and simulations provide visualization of the distinct micro-morphologies of the CL corresponding to each nano-particle size. The results are analyzed using pair correlation functions, showing that different microstructures are obtained for different Pt nano-particle sizes, and also that inclusion of PFSI in the simulations impacts significantly the final configuration of Pt nano-particles. Water molecules are found to distribute near the side chains of PFSI and surface of Pt nano-particles, but far from the graphite surface. Side chains form clusters and exhibit different dispersion toward the Pt surface. The orientations of the side chains in the vicinity of the Pt surface are analyzed in detail. The dispersion of perfluorosulfonate ionomer is found to strongly influence the merging of Pt nano-particles and, consequently, the CL microstructure formation.     

纳米粒子填充PTFE摩擦副材料的研究进展

综述国内外纳米粒子填充聚四氟乙烯(PTFE)摩擦副材料的研究进展,对纳米粒子填充后的减摩抗磨机理进行探讨,提出“滚珠轴承”、膜润滑和界面束缚作用三个观点,分析该项研究在纳米粒子分散技术和纳米粒子与PTFE基体界面处理上存在的不足,并结合复合材料界面处理机理、PTFE表面粘结机理和纳米粒子分散机理,提出一些新的纳米粒子填充PTFE复合材料界面改性和分散技术的方法。