超细TATB-BTF核-壳型复合粒子的制备

用喷雾干燥法制备了超细TATB-BTF核-壳型复合粒子。通过BTF在TATB表面结晶沉积,达到对超细TATB粒子进行包覆的目的。扫描电镜分析显示粒子表面形态发生了一定变化,表明TATB粒子表面有包覆层,用光电子能谱(XPS)对粒子表面各成分含量进行了分析。对复合粒子的热行为进行了DTA分析。结果表明,核粒大小是影响超细TATB-BTF核-壳型复合粒子包覆效果的主要因素。     

有机/无机纳米复合粒子平衡型态的热力学计算——粒子型态的转化率依赖性

有机/无机纳米复合粒子是一种性能优异的纳米复合材料,基于分裂/融合过程的细乳液聚合是制备此类复合粒子的新型方法。从热力学角度出发,基于界面Gibbs自由能最低原理推导了核壳型、半球型、夹心型和分离型有机/无机纳米复合粒子平衡型态的界面Gibbs自由能方程,考虑了聚合过程中单体转化率对纳米复合粒子热力学平衡型态的影响,扩展了上述方程应用范围。将这些热力学方程用于炭黑/（聚）苯乙烯/水体系中,发现当无机颗粒体积分数小于0.2时,核壳型纳米复合粒子的界面Gibbs自由能最低;随着单体转化率的增加,核壳型、半球型和夹心型复合粒子的界面Gibbs自由能略有下降,这可能是由于聚苯乙烯/水相的界面张力略低于苯乙烯/水相的数值造成的。     

Equilibrium morphology calculation of organic/inorganic nano-composite particles controlled by thermodynamics—dependence on monomer conversion

有机/无机纳米复合粒子是一种性能优异的纳米复合材料,基于分裂/融合过程的细乳液聚合是制备此类复合粒子的新型方法。从热力学角度出发,基于界面Gibbs自由能最低原理推导了核壳型、半球型、夹心型和分离型有机/无机纳米复合粒子平衡型态的界面Gibbs自由能方程,考虑了聚合过程中单体转化率对纳米复合粒子热力学平衡型态的影响,扩展了上述方程应用范围。将这些热力学方程用于炭黑/（聚）苯乙烯/水体系中,发现当无机颗粒体积分数小于0.2时,核壳型纳米复合粒子的界面Gibbs自由能最低;随着单体转化率的增加,核壳型、半球型和夹心型复合粒子的界面Gibbs自由能略有下降,这可能是由于聚苯乙烯/水相的界面张力略低于苯乙烯/水相的数值造成的。     

聚吡咯/无机纳米粒子复合材料的制备及其电磁屏蔽性能研究进展

综述了聚吡咯（PPy）包覆无机纳米粒子复合材料的主要制备方法及其在电磁屏蔽领域的研究进展,重点讨论了金属单质、氧/碳/氮化物以及碳系材料这三大类无机纳米粒子与PPy复合构成的核壳结构材料的电磁屏蔽性能及相关屏蔽机理。结果表明,核壳结构能够集PPy和无机纳米粒子各自的优势于一体,并发挥二者的协同效应,该方法是制备新型电磁屏蔽材料的一种有效途径。     

有机核-无机壳型复合粒子的研究进展

有机-无机核壳型复合材料因其优良的性能而成为近年来的研究热点。本文简述了制备有机核-无机壳型复合粒子的2种方法:化学法和物理法;重点对壳层为氧化物和金属单质、核为聚合物的复合粒子的制备及应用进行了讨论;分析了目前有机核-无机壳型复合粒子研究中存在的不足,并对其发展趋势进行了展望。     

聚苯乙烯/无机粒子(核/壳)复合微球的制备与研究进展

综述了近年来国内外聚苯乙烯(PS)/无机粒子(核/壳)复合微球的制备方法,如化学沉积法、静电自组装法和化学镀法等,简述了PS/无机粒子(核/壳)复合微球的优异性能及其应用,展望了PS/无机粒子(核/壳)复合微球的发展前景。     

核—壳型乳液聚合

介绍了核－壳型乳液聚合物的聚合机理,制备和表征方法,粒子形态及其影响因素,对于复合高分子乳液的设计具有重要意义。     

乳液聚合法制备核(二氧化钛)-壳(聚苯乙烯)复合粒子

研究了乳液聚合技术用于聚苯乙烯(polystyrene,PS)包覆改性二氧化钛(TiO2)纳米粒子.十二烷基硫酸钠(sodium dodecyl sulfate,SDS)作乳化剂,考察了其浓度对复合粒子形态的影响.用Fourier红外光谱、透射电镜和热重分析表征了无机-有机核-壳复合粒子.用沉降实验评价复合粒子的分散性和分散稳定性.实验表明:SDS浓度为0.8mg/mL时,可以实现PS对纳米TiO2粒子的成功包覆.最佳条件下,乳液聚合单体转化率达62.0%:包覆效率为54.0%;复合粒子中PS占62.6%;复合粒子平均粒径为181nm.复合粒子能在乙酸乙酯中形成均匀分散体系.     

核壳粒子研究进展

与传统的复合材料相比,核壳粒子在结构和性能方面有着明显的优势。由于能将两相或多相组分在分子水平上复合,因此,可以通过各组分的协调作用表现出其独特的性能。介绍了几种核壳粒子的特点及最新研究进展,包括无机-无机型、无机-有机型、有机-有机型核壳粒子以及多层核壳粒子,最后指出核壳粒子研究面临的问题及未来的发展方向。     

溶胶-凝胶法制备包覆粉的研究现状

具有核壳结构的包覆型复合粉末,兼具包壳层材料和内核材料两种物质的优良性能。溶胶-凝胶法用于制备陶瓷包覆型复合粉体,可以实现涂层包覆,且包覆层组织结构均匀致密。该文对溶胶-凝胶法制备陶瓷包覆型复合粉体的制备原理、方法及制备过程中各环节的影响因素进行了概述和分析;介绍了溶胶-凝胶法制备包覆型复合粉末的各类应用及其发展趋势。     

聚对苯撑乙烯类共聚物／TiO2复合材料光物理性能的研究

两种经过化学修饰的PPV（聚对苯撑乙烯）类共轭高分子共聚物分别与纳米TiO2复合，作为有机／无机复合材料进行研究。这两 人聚物在乙醇、二氯甲烷溶液中分别与以Sol-Gel法、反胶束法制得的TiO2共混得到均匀分散的体系而不出现相分离，用共聚物与TiO2的复合液可以在石英基底上制成均匀的复合膜，结果表明，高聚物／TiO2复合物的光物理特性与单纯的高聚物相比呈现明显的差异；不同粒径的纳米TiO2以复合物性能的影响不同；中间苯环的聚代基对共聚物的性质影响明显，共轭高分子与纳米TiO2复合涂膜后其发光性能明显改善，有作为发光器件的应用前景。     

Electrical properties of composites as affected by the degree of mixedness of the conductive filler in the polymer matrix

The development of the electrical properties of composites as a function of the degree of mixedness of a conductive filler distributed into an insulating polymer is investigated. A wide‐angle X‐ray diffraction (WAXD)‐based quantitative phase analysis method was used to characterize the variations of the concentrations of the insulating binder and the conductive particles around their mean values as a function of mixing time in an intensive batch mixer. Increasing the time and hence, the specific energy input, during the mixing process results in a more homogeneous spatial distribution of the conductive filler in the polymeric matrix, which in turn results in a decrease of the volume conductivity of the composite. The decreasing conductivity of the composite is attributed to the better coating and hence the isolation of the conductive particles from each other, thus hindering the formation of a conductive network “percolation”. Overall, these results suggest that the control of the electrical properties of conductive composites could benefit from a good understanding and adequate control of the dynamics of the mixing process and the resulting degree of mixedness of the conductive particles in the polymer matrix.     

Behavior of Pressure-Sensitive Adhesives Filled with Metallized Inorganic Particles

The electrically conductive pressure-sensitive composite adhesives based on acrylic polymer and silver-coated inorganic particles have been investigated in this article. The electrical conductivity of the pressure-sensitive adhesives containing silver coated spherical inorganic particles is lower at the same concentration of the filler in comparison with silver coated inorganic fibers, the strength of adhesive joint to aluminum being higher in the case of the pressure-sensitive adhesive containing silver-coated inorganic fibers. After the thermal treatment the strength of adhesive joint to aluminum of electrically conductive pressure sensitive adhesives increases significantly. The suitable concentration proposition of the silver-coated inorganic filler in the pressure-sensitive adhesive requires a compromise solution of the problem taking into account the ultimate adhesive and electrical properties of the investigated pressure-sensitive adhesives composites.     

Thermal conductivity of polymer-based composites: Fundamentals and applications

Thermal management is critical to the performance, lifetime, and reliability of electronic devices. With the miniaturization, integration and functionalization of electronics and the emergence of new applications such as light emitting diodes, thermal dissipation becomes a challenging problem. Addressing this challenge requires the development of novel polymer-based composite materials with enhanced thermal conductivity. In this review, the fundamental design principles of highly thermally conductive composites were discussed. The key factors influencing the thermal conductivity of polymers, such as chain structure, crystallinity, crystal form, orientation of polymer chains, and orientation of ordered domains in both thermoplastics and thermosets were addressed. The properties of thermally conductive fillers (carbon nanotubes, metal particles, and ceramic particles such as boron nitride or aluminum oxide) are summarized at length. The dependence of thermal conductivity of composites on the filler loading, filler aggregate morphology and overall composite structure is also discussed. Special attention is paid to recent advances in controlling the microstructure of polymer composites to achieve high thermal conductivity (novel approaches to control filler orientation, special design of filler agglomerates, formation of continuous filler network by self-assembly process, double percolation approach, etc.). The review also summarizes some emerging applications of thermally conductive polymer composites. Finally, we outline the challenges and outlook for thermally conductive polymer composites.     

聚苯胺/无机粒子复合材料的研究进展

主要综述了纳米聚苯胺与无机粒子(如无机磁性粒子、金属氧化物、碳基无机物等其他无机粒子)复合制备的功能性复合材料的力学、光学、电学和磁学性能以及此类功能性复合材料在金属防腐和防污、电磁屏蔽、光学催化、电池材料以及化学传感器等方面的应用前景,并介绍了近几年来各类纳米聚苯胺/无机粒子功能性复合材料在电磁屏蔽、隐身材料、抗静电材料、导电高分子电容器、发光二极管以及二次电池等方面的研究现状及未来发展趋势.     

聚合物/新型导热填料复合电介质的研究进展

综述了非常规新型导热粒子如纳米金刚石、碳化物、铁电陶瓷及其他无机功能粒子及其填充聚合物电介质的最新研究进展,重点探讨了新型导热粒子的含量、表面改性、加工方式等对聚合物复合材料的导热及介电性能的影响。介绍和分析了基于有机分子晶体为连续声子传递通路改性聚合物导热性能的研究及机理;在基体树脂内利用无机导热粒子及有机分子晶体可构筑连续的声子导热通路,从而达到降低界面热阻、提高体系热导率的目的。相比传统导热粒子,新型导热粒子在提高绝缘聚合物热导率的同时,还赋予体系其他物理性能如磁性、优良介电性能及储能等性能。     

填充型导电高分子复合材料的逾渗理论进展

总结了粒子填充型导电体系逾渗网络的形成及逾渗理论概况，以热力学和动力学的观点对导电粒子种类、形状、浓度、分布和分散、基体树脂的种类、粒子与基体树脂的相互作用、加工条件等影响逾渗的重要因素作了系统的分析，阐明了体系的导电性、微观形貌、流变性能和物理性能的相互关系。对低逾渗值填充聚合物尤其是炭黑复合材料的成型与加工提供了理论指导。     

Nylon 6 induced morphological developments and electrical conductivity improvements of polypropylene/carbon black composites

In this study, a polar conductive filler [carbon black (CB)], a nonpolar polymer [polypropylene (PP)], and a polar polymer [nylon 6 (PA6)] were chosen to fabricate electrically conductive polymer composites by melt blending and compression molding. The morphological developments of these composites were studied. Scanning electron microscopy results showed that in a CB‐filled PP/PA6 (CPA) composite, CB particles were selectively dispersed in PA6 phases and could make the dispersed particles exist as microfiber particles, which could greatly improve the electrical conductivity. The PA6 and CB contents both could affect the morphologies of these composites. The results of electrical resistivity measurements of these composites proved the formation of conductive networks. The resistivity–temperature behaviors of these composites were also studied. For CB‐filled PP (CP) composites, there were apparent positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects and an unrepeatable resistivity–temperature characteristic. However, for CPA composites, there were no PTC or NTC effects from room temperature to 180°C, and the resistivity–temperature behavior showed a repeatable characteristic; this proved that CB particles were selectively dispersed in the PA6 phase from another point of view. All experimental results indicated that the addition of PA6 to a CP composite could lead to an expected morphological structure and improve the electrical conductivity of the CP composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Recent Progress on Fabrication and Performance of Polymer Composites with Highly Thermal Conductivity

The rise of miniaturized, integrated, and functional electronic devices has intensified the need for heat dissipation. To address this challenge, it is necessary to develop novel thermally conductive polymer composites as packaging materials. In this paper, a number of factors for the construction and design of thermally conductive polymers are concluded. Special attention is focused on the analysis and comparison of the thermally conductive composites prepared by various fillers or strategies to provide guidelines and references for future design of composite materials. The current commonly used preparation strategies of thermally conductive polymer are summarized, such as using a variety of fillers, vacuum filtration, template method, and so on. The challenges of thermally conductive polymer composites are finally sketched. This review can inspire the design of polymer composites with brilliant thermal conductivity.     

Influences of dielectric and conductive fillers on dielectric and mechanical properties of solid silicone rubber composites

Dielectric elastomers are materials being used for electromechanical transduction applications. Their electromechanical response depends on permittivity, Young’s modulus and electric breakdown strength. A factor that limits its application is high operating voltages that can be reduced through improvement in permittivity. One of the methods is by incorporating high permittivity fillers into polymer matrix to obtain dielectric–dielectric composites (DDC).These composites show high permittivity at the cost of reduced flexibility. An alternative solution is development of composites by incorporating organic or inorganic conductive fillers into polymer matrix. These composites show high permittivity with high dielectric loss and low breakdown strength. To overcome both the above limitations both dielectric and conductive fillers are incorporated into dielectric polymer matrix to obtain conductor–dielectric composites (CDC). In this study, high temperature vulcanized solid silicone rubber as matrix has been used to prepare DDC composites with barium titanate (BT) filler and CDC composites with both BT as dielectric and ketjenblack as conductive fillers, using Taguchi design of experiments. The effect of factors such as amount of fillers and curing agent, mixing time in roll mill and curing temperature on the dielectric and mechanical properties are reported. Lichtenecker model predicts the permittivity of the DDC composite more accurately. For the CDC composites permittivity increased by 390%, effective resistivity decreased by 80%, Young’s modulus increased by 368% and Shore A hardness increased by 90% as compared to those of reference matrix. Important interaction effects are observed among both the fillers that are uniformly dispersed without any aggregation.