聚偏氟乙烯基导热复合材料的制备及表征

发布时间：2018-05-22 12:16

本文选题：PVDF复合材料 + 碳纳米管　；参考：《西南交通大学》2015年硕士论文

【摘要】：聚合物因其具有优良的加工性能、耐化学腐蚀、成本低廉等特点,在电子封装等领域有广泛的应用。随着电子领域与封装技术的飞速发展,电子产品的体积成千万倍地缩小,而电子产品工作速度越来越过,此时电子设备发热现象愈发明显,使得电子产品的运行效率下降、死机甚至会引发火灾等危害。聚合物导热性能较差,不足以满足工业生产对散热性能的需求,而选用高导热性能填料对聚合物材料进行填充改性已经成为工业常用的提高材料导热性能的手段。因此,研究制备高导热性能高分子材料具有十分重要的意义。本文针对聚偏氟乙烯(Polyvinylidene fluoride, PVDF)基导热复合材料中界面热阻、导热填料网络、极性晶体等对复合材料导热性能的影响规律及其作用机制开展研究工作,旨在掌握改善PVDF复合材料导热性能的方法和技术,阐述其机理,以期为具有高导热系数的PVDF复合材料的开发与应用提供理论支撑和技术指导。主要研究成果如下：(1)首先利用聚乙烯吡咯烷酮(Polyvinyl pyrrolidone, PV P)对碳纳米管(Carbon nanotubes, CNTs)物理包覆制备CNTs@PVP,再通过熔融共混法制备复合材料PVDF/CNTs和PVDF/CNTs@PVP。通过对复合材料导热性能、结晶行为、流变行为、微观形貌的表征,研究PVP对CNTs的分散以及界面热阻的影响。导热系数测试结果表明,当CNTs、PVP含量分别为10wt%、1wt%时,复合材料的导热系数升高至0.63W/mK,达到PVDF导热系数的3倍之多；通过结晶行为研究发现PVP不会引起PVDF晶型的变化；形貌表征及流变行为说明PVP的引入大幅地改善CNTs的分散并构建更致密的导热网络；通过红外分析发现PVP与PVDF间存在氢键作用。综合上述分析表明,CNTs致密的网络结构及PVDF与CNTs间界面相互作用的增强是PVDF/CNTs@PVP复合材料导热性能提高的主要原因。(2)通过溶液共混法将氧化石墨烯(Graphene oxide, GO)引入到复合材料PVDF/CNTs中,制备PVDF/CNTs/GO复合材料。通过形貌表征、流变行为研究发现,GO促进CNTs的分散,并与CNTs形成致密的三维填料网络结构；通过导热性能测试及理论模拟计算发现,GO与CNTs所构建三维导热网络结构是导热性能提高的主要原因。此外,结晶行为研究表明,GO诱导PVDF生成大量极性的y晶体。这意味着GO的引入不但可以降低PVDF/CNTs导热复合材料的生产成本,而且可使PVDF具有更多的潜在应用价值。(3)将离子液体(Ionic liquid, IL)添加到PVDF中,制备共混物PVDF/IL。通过对PVDF结晶行为的研究发现,IL诱导PVDF生成了β极性晶体,并且极性晶体相对含量随IL含量增加而增加；导热测试结果表明,极性晶体的生成有利于PVDF导热性能的提高；初步探索了极性晶体对复合材料导热性能的影响,为进一步改善聚合物导热性能提供了新的研究思路。
[Abstract]:Because of its excellent processing performance, chemical corrosion resistance and low cost, polymer has been widely used in electronic packaging and other fields. With the rapid development of electronic and packaging technology, the volume of electronic products is narrowing, and electronic products work faster and faster. At this time, the heating phenomenon of electronic equipment is becoming more and more obvious. The operation efficiency of the electronic products decreases and the dead machine may even cause the damage of the fire. The poor thermal conductivity of the polymer is not enough to meet the demand for the heat dissipation of the industrial production. And the use of high thermal conductivity filler to fill in the polymer material has become a commonly used means to improve the thermal conductivity of the materials. The preparation of high thermal conductivity polymer materials is of great significance. In this paper, the effect of thermal conductivity of the composite materials on the thermal conductivity of Polyvinylidene fluoride (PVDF) based thermal conductive composites, thermal conductive filler network, polar crystal and so on, is studied to improve the PVDF complex. The methods and techniques of thermal conductivity of the composite materials are described in order to provide theoretical support and technical guidance for the development and application of PVDF composites with high thermal conductivity. The main research results are as follows: (1) first, the physical package of carbon nanotubes (Carbon nanotubes, CNTs) with polyvinylpyrrolidone (Polyvinyl pyrrolidone, PV P) CNTs@PVP was prepared, and the composite material PVDF/CNTs and PVDF/CNTs@PVP. were prepared by melt blending. Through the characterization of thermal conductivity, crystallization behavior, rheological behavior and Micromorphology of the composites, the influence of PVP on the dispersion of CNTs and the thermal resistance of the interface was studied. The thermal conductivity test results showed that when CNTs, PVP content was 10wt%, 1wt%, composite. The thermal conductivity of the material is up to 0.63W/mK, up to 3 times of the PVDF thermal conductivity. Through the crystallization behavior study, it is found that PVP does not cause the change of the PVDF crystal. The morphology characterization and the rheological behavior indicate that the introduction of PVP greatly improves the dispersion of CNTs and constructs a more compact heat conduction network, and the existence of hydrogen between PVP and PVDF through the infrared analysis is found. The above analysis shows that the dense network structure of CNTs and the enhancement of the interface interaction between PVDF and CNTs are the main reasons for improving the thermal conductivity of PVDF/CNTs@PVP composites. (2) the oxidation Shi Moxi (Graphene oxide, GO) is introduced into the composite PVDF/CNTs by solution blending, and the PVDF/CNTs/GO composite material is prepared. The morphology characterization and rheological behavior study found that GO promotes the dispersion of CNTs and forms a compact three-dimensional packing network structure with CNTs. Through thermal conductivity testing and theoretical simulation, it is found that the three dimensional heat conduction network structure constructed by GO and CNTs is the main reason for the improvement of thermal conductivity. In addition, the crystallization behavior study shows that GO induces PVDF to produce a large amount of PVDF. Polar y crystal. This means that the introduction of GO can not only reduce the production cost of PVDF/CNTs thermal conductive composite, but also make PVDF have more potential application value. (3) adding the ionic liquid (Ionic liquid, IL) to PVDF, and preparing the blend PVDF/IL. through the study of the crystallization behavior of PVDF, the IL inducible PVDF generates beta polarity. The relative content of crystal increases with the increase of IL content, and the thermal conductivity test results show that the formation of polar crystals is beneficial to the improvement of the thermal conductivity of PVDF, and the effect of polar crystals on the thermal conductivity of the composites is preliminarily explored, which provides a new way to further improve the thermal conductivity of the polymer.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

【参考文献】