碳纳米管/聚合物基导热复合材料研究进展

碳纳米管（CNTs）由于优异的轴向导热性能,是目前制备高热导率聚合物基复合材料的一类重要填料。本文综述了近年来CNTs增强聚合物复合材料的研究进展,探讨了CNTs/聚合物复合材料的导热机理以及CNTs用量、尺寸及结构、表面改性、混杂CNTs粒子和聚合物基体结构等因素对CNTs/聚合物复合材料热导率的影响。同CNTs/聚合物的电导率相比,热导率远低于预期值,归因于CNTs/树脂界面间的声子频率失配现象导致了声子在界面的散射及很高的界面接触热阻,从而降低了体系热导率。分析和总结了改善体系热导率的方法和措施,采用特殊工艺使CNTs在基体内形成特殊的隔离结构或者取向结构是CNTs/聚合物导热复合材料的未来研究及发展方向。     

纳米粒子改性丙烯酸酯制备复合材料

作为分散相的纳米粒子以独立的相态形式通过改性,分散到作为连续相的丙烯酸酯聚合物基体中形成一种既保留无机材料的热稳定性与硬度,又兼具聚合物韧性与介电性能的复合材料,该过程不是无机相与有机相的简单混合,而是在纳米尺度内两相的有机复合。综述了近年来纳米粒子改性丙烯酸酯复合材料,重点介绍了纳米粒子种类、纳米粒子表面改性、复合材料制备方法及其工业应用等方面的研究成果,并对其发展方向进行了分析和展望。     

聚合物/BN导热复合材料研究进展

与其他导热无机粒子相比,氮化硼粒子具有的独特结构及良好的热、电综合性能,是制备高导热、高绝缘聚合物的一类重要导热绝缘填料。综述了微、纳米氮化硼粒子填充导热聚合物的研究进展,重点讨论了氮化硼粒子的物理性能、表面改性、结构及用量等对聚合物导热、绝缘及力学性能的影响。与微米氮化硼相比,氮化硼纳米管及纳米片增强的聚合物具有高导热、高电击穿强度、高绝缘电阻、低介电常数及介电损耗、良好的力学性能。解决导热聚合物高导热与高电击穿强度间的矛盾是聚合物/氮化硼导热复合材料未来发展的方向。     

改善聚合物热导率的研究进展

分别从导热填料粒子性质、聚合物基体、两相界面结构性质,以及材料加工工艺等角度出发,深入探讨了影响聚合物热导率的因素和机制,总结了提高和改善聚合物导热性能的方法。提高导热粒子和基体的热导率,在聚合物基体内形成稳定的最大化导热粒子通路等措施均可有效改善聚合物热导率。     

导热高分子复合材料研究进展

在介绍金属材料、无机非金属材料以及高分子材料导热机理的基础上,介绍了导热填料填充高分子复合材料的导热网链机理和热弹性组合机理2种导热机理,该理论可以解释导热高分子复合材料导热过程中不同的现象和规律;归纳了适用于粒子、纤维等填充的聚合物基复合材料的各种导热模型;讨论了树脂基体、导热填料和温度对于高分子复合材料热导率的影响...     

导热橡胶复合材料研究进展

介绍填充型导热橡胶复合材料的研究进展及其发展方向。填充型导热橡胶复合材料以其高热导率、低压易变形、密封性好等优点被广泛应用于热界面导热材料。制备导热橡胶的常用填料主要有金属、碳、氮化物、氧化物、碳化物等,填料类型、尺寸、表面改性及材料加工方法等因素对导热橡胶热导率产生影响,提高导热橡胶热导率可从这些因素入手进行调控。未来一定时期内,对导热橡胶的研究将围绕导热填料表面处理新方法、导热填料与橡胶基体界面优化、混杂复配技术、新型加工技术、导热填料在基体中的结构演化及其对导热通路的调控等方面进行。     

聚合物基导热电子封装材料的研究进展

概述了电子封装材料常用的基体材料、导热填料及制备方法。阐述了聚合物本征导热的影响因素及填料物理性能对聚合物基复合体系导热性能的影响。重点介绍了复合型导热聚合物的导热机理、导热模型以及提高复合体系热导率的途径。对今后的研究工作提出了建议。     

聚合物基导热绝缘复合材料的制备及逾渗模型的应用

采用乙烯一醋酸乙烯a共聚物和无机导热填料制备聚合物基导热绝缘复合材料,概述了以逾渗理论为基础的热导率计算模型,并应用所制备的导热绝缘复合材料讨论了逾渗模型的准确性。结果表明,SiC填充的复合材料具有较好的导热性能;填料体积分数达0.5时,复合材料的热导率可达1.86 W/(m0K)。研究表明,简单地运用逾渗理论在预测导热复合材料体系的热导率方面准确性不足,需要进一步考虑实际填料粒子分布与理论假设的差异以及界面相的存在等因素的影响。     

导热凝胶的研究进展

概述导热凝胶的组成和导热机理，介绍硅系导热凝胶基体和非硅系导热凝胶基体以及陶瓷材料、碳基材料和复合填料作为导热填料的研究进展。导热凝胶具有热导率大，耐高低温性能和绝缘性能好，塑性、粘性和附着性强，且可重复使用等优点。导热凝胶综合性能提高的关键在于合理设计基体和填料的性质，基体的设计可以从聚合物的类型和相对分子质量及其分布、交联剂、扩链剂等方面进行，并从改变分子链的结构和排列等方面改性聚合物；填料的设计可以从提高导热性能方面进行，如对传统导热填料进行表面功能化以及设计复合填料。     

酒石酸改性BT增强PP复合材料导热与介电性能

以酒石酸为改性剂,对钛酸钡（BT）颗粒进行表面改性,制备了聚丙烯（PP）/纳米氧化铝（Al₂O₃）/改性BT系列3相复合材料。通过傅里叶红外光谱、扫描电子显微镜、介电频谱仪、导热分析仪对复合材料的红外光谱、微观形貌、介电性能、导热性能等进行分析表征。结果表明,酒石酸对BT颗粒的表面改性能有效改善BT、Al₂O₃等无机填料与PP聚合物的相容性,进而改善与聚合物基体间的界面连接,促进BT、Al₂O₃等颗粒在PP中的均匀分散,从而同时提升复合材料的导热和介电性能;当PP、BT与Al₂O₃的体积比为5∶4∶1时,改性BT/Al₂O₃/PP 3相复合材料的导热系数由0.90 W/m?K提升至1.24 W/m?K,在100 Hz时的相对介电常数由18提高到21.2,介电损耗同时由0.055降低至0.035,在25～130 ℃的温度区间中,改性后的复合材料介电性能保持优异的温度稳定性,介电常数温度系数为-124×10^?6 ℃^?1,比未改性复合材料的介电常数温度系数降低了62.8 %。     

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.     

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.     

某高导热纤维及其复合材料性能研究

研究了某高导热纤维/环氧树脂单向层复合材料的导热系数和力学性能,发现某高导热纤维/环氧树脂单向层复合材料导热性能提高的同时其个别复合材料性能降低;分析认为某高导热纤维与环氧树脂的界面性能是影响复合材料力学性能的重要因素,同时研究了某高导热纤维的表面微观形貌和表面化学特性、结晶度及某高导热纤维/环氧树脂浸胶丝束的力学性能...     

不同粒径氮化硼填充环氧树脂/玻璃纤维绝缘导热复合材料的研究

以聚砜改性环氧树脂为基体,通过高温模压制备了环氧树脂/玻璃纤维/氮化硼复合材料,研究了不同粒径及不同氮化硼导热粒子用量对复合材料导热性能、力学性能和电性能的影响。结果表明,大粒径粒子有利于复合材料力学性能的提高,小粒径有利于导热性能的提高;随着氮化硼用量的增加,复合材料的导热性能升高,力学性能呈现先增后降趋势,当氮化硼用量为10%(质量分数,下同)时,复合材料的冲击强度和弯曲强度均达到最佳,当氮化硼用量为20%时,复合材料仍保持较好的电性能。     

无机填料粒子的几何特征对环氧树脂灌封胶导热性能的影响

以Al2O3、Si3N4、BN、SiO2和AlN五种无机填料作为环氧树脂(EP)灌封胶的导热填料,研究了填料的种类、粒径大小和颗粒形态等对EP灌封胶热导率的影响。结果表明:EP灌封胶的热导率随着导热填料用量的增加而增大;当φ(BN)=35%(相对于总体积而言)时,相对最大热导率为2.12 W/(m·K),其值约为EP基体的10倍。填料粒子的几何特征对EP灌封胶的导热性能具有较大的影响;当Al2O3粒径为48μm时,EP灌封胶的相对最大热导率为1.3 W/(m·K);填料粒子过大或过小都会降低EP灌封胶的导热性能。层片状填料粒子可以获得较大的堆积密度,在EP灌封胶中能有效形成导热通道,增加其热导率。     

聚合物/导热金属复合材料的研究进展

综述了聚合物/金属粒子导热复合材料的最新研究进展,重点探讨了金属粒子的种类、形状及大小、用量、加工方式及核壳结构等对复合材料热导率的调控及影响机理。在低填料用量时采用特殊加工手段在基体内构筑有利于声子传递的连续导热粒子通道,可得到优良综合性能的高导热聚合物复合材料;适应于可穿戴电子及柔性电子器件散热的液体合金/弹性聚合物在大尺度形变下具有良好的导热能力,是导热聚合物未来发展的重要方向。     

高导热高介电BT/SiC/PA6复合材料的制备及性能研究

以聚酰胺(PA6)为基体,氮化硅(SiC)为导热填料,钛酸钡(BT)为介电填料,通过热压法制备出系列复合材料;研究了不同粒径填料的搭配对材料导热与介电性能的影响。结果表明:在填充量较低时,使用混合粒径导热填料能产生一定的级配效应,从而提高复合材料的导热性能。总填充量为26%时,以4∶1的比例,用粒径为0.5~0.7μm和3μm的SiC共同填充PA6,制备获得了最高导热系数为0.9198W/(m·K)的复合材料,而不同粒径、不同功能的混合功能填料还能产生协同效应,进一步提升材料的导热性能并使材料同时获得较好的介电性能,当SiC填充量为20%,BT填充量为20%时,复合材料的导热系数达到1.1110W/(m·K),介电常数到达16(100Hz),损耗保持在0.075(100Hz)左右。     

Influence of filler type and content on thermal conductivity and mechanical properties of thermoplastic compounds

Combining thermal conductivity with electrical isolation is a very interesting topic for electronic applications in order to transfer the generated heat. Typical approaches combine thermally conductive fillers with a thermoplastic matrix. The aim of this work was to investigate the influence of different fillers and matrices on the thermal conductivity of the polymer matrix composites. In this study, various inorganic fillers, including aluminum oxide (Al₂O₃), zinc oxide (ZnO), and boron nitride (BN) with different shapes and sizes, were used in matrix polymers, such as polyamide 6 (PA6), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethane (TPU), and polysulfone (PSU), to produce thermally conductive polymer matrix composites by compounding and injection molding. Using simple mathematical models (e.g., Agari model, Lewis–Nielson model), a first attempt was made to predict thermal conductivity from constituent properties. The materials were characterized by tensile testing, density measurement, and thermal conductivity measurement. Contact angle measurements and the calculated surface energy can be used to evaluate the wetting behavior, which correlates directly with the elastic modulus. Based on the aforementioned evaluations, we found that besides the volume fraction, the particle shape in combination with the intrinsic thermal conductivity of the filler has the greatest influence on the thermal conductivity of the composite.     

复合绝缘导热胶粘剂研究

以增韧的酚醛环氧树脂为基体树脂,氮化铝、氮化硼、氧化铝混杂粒子为导热填料制备了-新型绝缘导热胶粘剂。研究了填料用量对胶粘剂热导率、热阻、介电常数、体积电阻率等性能的影响,发现填料用量为40％时胶粘剂的热导率为O．99 W／mK,热阻为0．70℃／W,介电常数6,体积电阻率4．6×1012Ω·cm,20℃、200℃、250℃下的剪切强度分别为13．0MPa、10．0MPa、5．65MPa。研究结果表明该胶具备良好的电绝缘及力学性能,可以长期在150℃温度下使用,与不加导热填料的相同胶粘剂相比,具有良好的导热能力。     

High Thermal Conductivity Polymer Composites Fabrication through Conventional and 3D Printing Processes: State-of-the-Art and Future Trends

The lifespan and the performance of flexible electronic devices and components are affected by the large accumulation of heat, and this problem must be addressed by thermally conductive polymer composite films. Therefore, the need for the development of high thermal conductivity nanocomposites has a strong role in various applications. In this article, the effect of different particle reinforcements such as single and hybrid form, coated and uncoated particles, and chemically treated particles on the thermal conductivity of various polymers are reviewed and the mechanism behind the improvement of the required properties are discussed. Furthermore, the role of manufacturing processes such as injection molding, compression molding, and 3D printing techniques in the production of high thermal conductivity polymer composites is detailed. Finally, the potential for future research is discussed, which can help researchers to work on the thermal properties enhancement for polymeric materials.