高性能钛酸钡/聚合物复合材料的研究进展

具有高介电常数(k)的钛酸钡/聚合物复合材料,兼有钛酸钡陶瓷和聚合物的各自优势,是一种有广泛应用前景的电子材料,因而备受关注。综合给出了近5年来高性能钛酸钡/聚合物复合材料的研究进展,分析指出了原材料选择、制备工艺及其对复合材料介电性能的影响,概括介绍了这类复合材料的主要应用,预测展望了其未来的发展趋势。     

聚合物基纳米复合材料的合成、性能及应用前景

介绍了聚合物/无机纳米复合材料、聚合物/聚合物纳米复合材料的制备方法、性质、发展方向以及应用前景。对聚合物基纳米复合材料今后的发展提出了一些自己的见解。     

聚合物/层状硅酸盐纳米复合阻燃材料进展概述

介绍了聚合物/层状硅酸盐纳米复合材料的制备方法、结构特点和表征方法,同时对聚合物/层状硅酸盐纳米复合材料的阻燃机理和阻燃性能的应用做了简要说明.     

聚合物基纳米复合材料的界面作用研究进展

将聚合物与纳米粒子复合制备性能优异的聚合物基纳米复合材料是近20年来科学界的研究热点,其中聚合物与纳米粒子间的界面作用对复合材料的性能起着关键性作用。从界面结构、力学性能、热性能及计算机仿真模拟等方面综述了聚合物基纳米复合材料的界面研究进展,并对这一领域的研究进行了展望。     

两亲性聚合物/碳纳米管复合材料的研究进展

两亲性聚合物具有独特的pH/温度响应、自组装等特性,将其与碳纳米管结合制成的两亲性聚合物/碳纳米管复合材料具有广阔的应用前景.介绍了两亲性聚合物/碳纳米管复合材料的3种制备方法,即原子转移自由基聚合法、可逆加成-断裂链转移自由基聚合法和氮氧自由基聚合法,综述了两亲性聚合物/碳纳米管复合材料在两亲性、pH/温度响应性等方面的应用进展.     

PMMA纳米复合材料的研究进展和制备方法

主要介绍了PMMA/MWNT纳米复合材料、PMMA/层状硅酸盐纳米复合材料、PMMA/氧化物纳米复合材料这3种常见聚合物基纳米复合材料的制备方法,同时对每种体系特点进行了论述.最后指出纳米复合材料制备方法、应用以及开发新的PMMA基纳米复合体系是今后的主要研究方向.     

乳液聚合法制备纳米ZnO/聚合物复合材料的研究进展

纳米ZnO/聚合物复合材料结合了纳米ZnO优异的物理化学性能和聚合物易加工、高强度的特点,可广泛应用在电子、环保、化工、生物工程等领域。乳液聚合法因工艺简单、安全,条件温和,成本低等优点被广泛用于制备纳米ZnO/聚合物复合材料。对乳液聚合法制备纳米ZnO/聚合物复合材料的研究现状进行了综述。首先阐述了制备纳米ZnO/聚合物复合材料的乳液聚合方法,并对各种方法进行比较;然后归纳了纳米ZnO/聚合物复合材料的形成机理,并对纳米ZnO/聚合物复合材料在光电、抗紫外与抗菌、涂料等方面的应用现状进行了总结;最后,提出了纳米ZnO/聚合物复合材料未来的发展方向。     

聚合物基纳米复合材料的合成、性质及应用前景

介绍了聚合物 无机纳米复合材料、聚合物 /聚合物纳米复合材料的制备方法、性质、发展方向以及应用前景。对聚合物基纳米复合材料今后的发展提出了一些自己的见解     

碳纳米管/聚合物基复合材料研究进展

具有独特结构与优异性能的碳纳米管(CNTs)已成为聚合物复合材料的理想添加剂。介绍了CNTs/聚合物复合材料的制备方法及其在力学、电学和热学性能研究中取得的最新进展。分析了CNTs的含量、分散性、取向性以及表面功能化等因素对复合材料性能的影响。提出了CNTs/聚合物复合材料研究过程中面临的一些问题,并展望了这类复合材料的应用前景。     

纳米银/聚合物复合材料的原位法制备技术综述

纳米银/聚合物复合材料结合了纳米银优异的物理化学性能和聚合物的易加工和成膜性的特点,被广泛应用于抗菌、催化和光电等领域。原位法具有工艺简单、成本低、可形成单分散的纳米粒子等优点,被广泛用于制备纳米银/聚合物复合材料。主要综述了纳米银/聚合物复合材料的原位制备方法,主要包括原位生成法、原位聚合法、双原位合成法,并提出了纳米银/聚合物复合材料的发展方向。     

Thermoelectric property tailoring by composite engineering

The tailoring of the thermoelectric properties (the sign and magnitude of the absolute thermoelectric power) was achieved by composite engineering. The techniques involved the choice of the reinforcing fibers (continuous or short) in a structural composite and the choice of the particulate filler between the laminae in a continuous fiber composite. The tailoring resulted in thermoelectric structural composites, including continuous carbon fiber polymer-matrix composites and short fiber cement-matrix composites. In addition, it resulted in thermocouples in the form of structural composites. The choice of fibers impacted the thermoelectric behavior in the fiber direction of the composite. The choice of interlaminar filler impacted the thermoelectric behavior in the through-thickness direction.     

Effect of electron donor/acceptor substituents on the Seebeck coefficient and thermoelectric properties of poly(3-methylthiophene methine)s/graphite composites

Recently, the use of polymers as thermoelectric materials has attracted considerable attention. However, relatively few studies have investigated the effects of polymer structures on the corresponding thermoelectric properties of the polymers. In this work, a series of poly(3-methylthiophene methine)s (PMMs) were synthesized for use as thermoelectric materials, and the effects on the Seebeck coefficient of donor or acceptor side groups at the methine carbon were studied. The PMMs with strongly electron-withdrawing and electron-donating groups exhibited the highest Seebeck coefficients. Motivated by the high Seebeck coefficients of the selected PMMs, PMM/graphite composites were prepared via solution mixing followed by mechanical ball milling and cold pressing. The thermoelectric properties of the composites were investigated as a function of the graphite (G) concentration. The highest ZT (6.23 × 10⁻³) was measured for the poly[(3-methylthiophene-2,5-diyl) (p-(methoxy)benzylidene)]/G composite that contained 90 wt% G. The results of this work suggest that the thermoelectric properties of polymer-inorganic composites can be improved by designing polymers with high Seebeck coefficients.     

The effective thermoelectric properties of core–shell composites

Thermoelectric materials are capable of converting heat directly into electricity and vice versa, and they have been explored for both waste heat recovery and thermal management. In this work, we analyze axially symmetric thermoelectric problems, motivated by energy harvesting using waste heat from an automobile exhaust pipe. Thermoelectric field distributions in both homogeneous shell and core–shell composites are solved, and the effective thermoelectric properties of the core–shell composites are analyzed. Numerical results show that higher thermoelectric conversion efficiency can be achieved in core–shell composites, and the mechanism responsible for the enhanced conversion efficiency is also identified. The analysis thus points to a new direction in developing high-performance thermoelectric materials.     

Thermoelectric power and AC electrical properties of PAN-based carbon fiber composites

The thermoelectric power and AC electrical properties of conductive polymer composites made of polycarbonate filled with randomly distributed PAN-based carbon fibers of different concentration: 0, 5, 10, 18, and 30 wt% were studied. The thermoelectric power was measured as a function of temperature in the frequency range from 200 kHz to 12 MHz. It was found that the observed Seebeck coefficient and thermoelectric activation energy depend on temperature, frequency and fiber concentration. The Seebeck coefficient calculated using the electrical transport theory of semiconductors decreases with both increasing temperature and carbon fiber content. The thermoelectric power results revealed that the composites function electrically as semiconductors. Dielectric constants and AC conductivity were calculated from impedance and phase angle measurements. It was found that both increase with increasing temperature. The activation energy and relaxation time decrease with increasing temperature measured and applied frequency. The thermoelectric power results indicated that electrical conduction in bulk composites is produced from a combination of transport processes involving: electrons, holes, ions and charged impurity motion in addition to protonic migration.     

水泥基复合材料热电效应综述:机制、材料、影响因素及应用

在水泥基复合材料中掺入功能填料会使其获得将热能转化为电能的热电效应，可用于环境热量转换收集、混凝土结构健康检测传感器和智慧交通系统等方面。本文总结了热电水泥基复合材料(TECC)的热电效应机制、常用的功能填料、制备过程及主要工程应用，重点分析了不同功能填料对TECC热电效应的增强效果和机制，及材料分散程度、水分、疲劳荷载、温度循环等因素对TECC热电效应的影响机制。本综述指明了TECC在理论和应用方面的研究新方向，对今后水泥基复合材料热电效应的实验设计和性能提升具有指导作用。      

碳系分散体填充聚合物基PTC复合材料的研究进展

总结了碳系分散体(包括碳黑、石墨、碳纤维)作为导电填料填充聚合物形成聚合物基PTC复合材料的研究进展。对聚合物基体及碳系导电填料进行共混或接枝改性是当前主要的研究方向。认为在碳系／聚合物体系中加入合适的金属系导电填料可能会更有利于提高复合材料的PTC强度和稳定性。     

功能性石墨烯改善聚合物介电性能的研究进展

目的对近年来使用改性石墨烯改善聚合物基复合材料介电性能的研究进行总结,指出今后的发展方向。方法总结通过石墨烯改性来改善其在聚合物的分散性和提高聚合物基石墨烯复合材料介电性能的方法;对比石墨烯/聚合物复合材料的复合工艺对其介电常数和介电损耗数值的变化,总结不同的改性方法对复合材料介电性能的影响。结论石墨烯作为一种性能较优的导电填料对材料介电性能影响巨大,然而,由于其物理分散性不好,极大地阻碍了石墨烯改性聚合物基高介电复合材料的发展。通过对石墨烯进行功能化改性修饰可以有效提高聚合物基复合材料的介电性能,这种材料可作为电活性聚合物,在很多需要高介电常数的电介质材料领域,如超级电容器、感应器、驱动器、智能包装和机器人等方面得到应用。     

Magnetic orientation of single-walled carbon nanotubes or their composites using polymer wrapping

Abstract

The magnetic orientation of single-walled carbon nanotubes (SWNTs) or the SWNT composites wrapped with polymer using poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] (MEHPPV) as the conducting polymer were examined. The formation of SWNT/MEHPPV composites was confirmed by examining absorption and fluorescence spectra. The N,N-dimethylformamide solution of SWNT/MEHPPV composites or the aqueous solution of the shortened SWNTs was introduced dropwise onto a mica or glass plate. The magnetic processing of the composites or the SWNTs was carried out using a superconducting magnet with a horizontal direction (8 T). The AFM images indicated that the SWNT/MEHPPV composites or the SWNTs were oriented randomly without magnetic processing, while with magnetic processing (8 T), they were oriented with the tube axis of the composites or the SWNTs parallel to the magnetic field. In polarized absorption spectra of SWNT/MEHPPV composites on glass plates without magnetic processing, the absorbance due to semiconducting SWNT in the near-IR region in horizontal polarized light was almost the same as that in vertical polarized light. In contrast, with magnetic processing (8 T), the absorbance due to semiconducting SWNT in the horizontal polarization direction against the direction of magnetic field was stronger than that in the vertical polarization direction. Similar results were obtained from the polarized absorption spectra for the shortened SWNTs. These results of polarized absorption spectra also support the magnetic orientation of the SWNT/MEHPPV composites or the SWNTs. On the basis of a comparison of the composites and the SWNTs alone, the magnetic orientation of SWNT/MEHPPV composites is most likely ascribable to the anisotropy in susceptibilities of SWNTs.     

Thermal conductivity of polymer composites based on the length of multi-walled carbon nanotubes

The anisotropic development of thermal conductivity in polymer composites was evaluated by measuring the isotropic, in-plane and through-plane thermal conductivities of composites containing length-adjusted short and long multi-walled CNTs (MWCNTs). The thermal conductivities of the composites were relatively low irrespective of the MWCNT length due to their high contact resistance and high interfacial resistance to polymer resins, considering the high thermal conductivity of MWCNTs. The isotropic and in-plane thermal conductivities of long-MWCNT-based composites were higher than those of short-MWCNT-based ones and the trend can accurately be calculated using the modified Mori-Tanaka theory. The in-plane thermal conductivity of composites with 2 wt% long MWCNTs was increased to 1.27 W/m·K. The length of MWCNTs in polymer composites is an important physical factor in determining the anisotropic thermal conductivity and must be considered for theoretical simulations. The thermal conductivity of MWCNT polymer composites can be effectively controlled in the processing direction by adjusting the length of the MWCNT filler.     

导热绝缘高分子复合材料的研究进展

介绍了导热绝缘高分子复合材料的导热机理及制备方法.论述了导热绝缘高分子复合材料的研究进展,包括导热绝缘填料、导热绝缘橡胶、导热绝缘塑料及导热绝缘胶粘剂的研究.最后阐述导热绝缘复合材料的应用及发展方向.