橡胶复合材料导热性能的空间量化分析及界面相影响研究
发布时间：2019-05-24 05:39
【摘要】：随着科技的飞速发展,导热高分子的应用越来越广泛,已经成为目前学者们研究的热点。本文实验制备了氮化铝填充三元乙丙橡胶复合材料,热探针法测量了其在不同填充分数下的导热性能并利用3D测量激光显微镜对其表面进行了观察。利用ANSYS有限元分析软件模拟了填料粒子的空间分布、粒径大小、粒径正态分布、界面相特性对橡胶复合材料导热性能的影响。同时,对单一球径填充时的空间量化分析及带有界面相模型的氮化铝三元乙丙橡胶复合材料进行了量化分析。研究表明：随着氮化铝填充量的增加,复合材料导热性能呈现线性增加趋势,填充氮化铝可以极大提高复合材料的导热性能。由于制备的复合材料中反光物质较多,利用3D测量激光显微镜很难直接观测到复合材料中氮化铝的分布情况。在填充单一粒径的粒子时,粒子在橡胶中的分布对复合材料导热性能的影响较大。填料粒子在基体中的多选择性可能形成分布较好的导热通路,极大的提高复合材料的导热性能。同时粒子也可能发生团聚或过于分散,不利于导热通路的形成,从而造成不同情况下复合材料的导热性能出现一定波动性。通过对二维随机模型的量化分析,得到了可以描述复合材料导热网链的参数——热流协同度。利用此参数值的大小可以判定复合材料导热性能的大小。而且小粒径粒子之间更容易相互接触形成有利于热量传递的导热网链。在填料填充率相同,粒径的平方满足正态分布时,标准差越小复合材料导热性能越大。但标准差为0.05时复合材料导热性能最为稳定。因此,粒径最优的情况应该控制粒径的平方标准差在0～0.05之间。氮化铝三元乙丙橡胶的实验值与模拟结果对比发现界面相对复合材料导热性能的影响不可忽略。我们对Maxwell模型进行修正得到了修正后三相Maxwell公式,同时通过修正的三相Maxwell模型公式可以反推出界面相厚度。通过模拟界面相对碳纳米管填充三元乙丙橡胶复合材料导热性能的影响发现：薄界面可以提高热量向碳纳米管的传输效率,但容易发生界面脱粘。厚界面可以增加粘结性,但影响了热量向碳纳米管的传输效率。因此在优化填充型复合材料时应该合理控制界面相厚度。提高碳纳米管复合材料时可以增加碳纳米管体积分数和界面相导热性能来实现。
[Abstract]:With the rapid development of science and technology, the application of thermal conductive polymers is more and more extensive, which has become the focus of scholars' research at present. In this paper, aluminum nitride filled ethylene-propylene rubber composites were prepared experimentally. the thermal conductivity of aluminum nitride filled ethylene-propylene rubber composites under different filling fraction was measured by thermal probe method, and the surface of the composites was observed by 3D laser microscope. The effects of spatial distribution, particle size, particle size normal distribution and interfacial phase characteristics on the thermal conductivity of rubber composites were simulated by ANSYS finite element analysis software. At the same time, the spatial quantitative analysis of single spherical diameter filling and the quantitative analysis of aluminum nitride ternary ethylene-propylene rubber composites with interface phase model were carried out. The results show that the thermal conductivity of the composites increases linearly with the increase of aluminum nitride content, and the thermal conductivity of the composites can be greatly improved by filling aluminum nitride with aluminum nitride. Because of the large number of reflective materials in the composites, it is difficult to directly observe the distribution of aluminum nitride in the composites by 3D measurement of laser microscope. When the particles with a single particle size are filled, the distribution of particles in rubber has a great influence on the thermal conductivity of the composites. The multi-selectivity of packing particles in the matrix may form a well distributed heat conduction path, which can greatly improve the thermal conductivity of the composites. At the same time, particles may be agglomerated or too dispersed, which is not conducive to the formation of thermal conduction path, resulting in certain fluctuations in the thermal conductivity of composites under different conditions. Through the quantitative analysis of the two-dimensional stochastic model, the heat flux synergy, which can be used to describe the heat conduction network chain of composite materials, is obtained. The thermal conductivity of the composites can be determined by using the parameter value. Moreover, small particle size particles are easier to contact with each other to form a heat conduction network chain which is conducive to heat transfer. When the filling rate is the same and the square of particle size satisfies the normal distribution, the smaller the standard deviation is, the greater the thermal conductivity of the composites is. However, the thermal conductivity of the composite is the most stable when the standard deviation is 0.05. Therefore, the square standard deviation of particle size should be controlled between 0 and 0.05 in the case of optimal particle size. The experimental results of aluminum nitride ternary ethylene-propylene rubber are compared with the simulation results. It is found that the effect of interface on the thermal conductivity of composites can not be ignored. The modified three-phase Maxwell formula is obtained by modifying the Maxwell model, and the interface phase thickness can be deduced by the modified three-phase Maxwell model formula. It is found that the thin interface can improve the heat transfer efficiency to carbon nanotube, but the interfacial debonding is easy to occur by simulating the effect of interface on the thermal conductivity of ethylene-propylene rubber composites filled with carbon nanotube. The thick interface can increase the adhesion, but affect the heat transfer efficiency to carbon nanotubes. Therefore, the interface phase thickness should be controlled reasonably when optimizing the filled composites. Increasing the volume fraction and thermal conductivity of carbon nanotube composites can be realized by increasing the volume fraction of carbon nanotube and the thermal conductivity of interface phase.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
本文编号：2484601
[Abstract]:With the rapid development of science and technology, the application of thermal conductive polymers is more and more extensive, which has become the focus of scholars' research at present. In this paper, aluminum nitride filled ethylene-propylene rubber composites were prepared experimentally. the thermal conductivity of aluminum nitride filled ethylene-propylene rubber composites under different filling fraction was measured by thermal probe method, and the surface of the composites was observed by 3D laser microscope. The effects of spatial distribution, particle size, particle size normal distribution and interfacial phase characteristics on the thermal conductivity of rubber composites were simulated by ANSYS finite element analysis software. At the same time, the spatial quantitative analysis of single spherical diameter filling and the quantitative analysis of aluminum nitride ternary ethylene-propylene rubber composites with interface phase model were carried out. The results show that the thermal conductivity of the composites increases linearly with the increase of aluminum nitride content, and the thermal conductivity of the composites can be greatly improved by filling aluminum nitride with aluminum nitride. Because of the large number of reflective materials in the composites, it is difficult to directly observe the distribution of aluminum nitride in the composites by 3D measurement of laser microscope. When the particles with a single particle size are filled, the distribution of particles in rubber has a great influence on the thermal conductivity of the composites. The multi-selectivity of packing particles in the matrix may form a well distributed heat conduction path, which can greatly improve the thermal conductivity of the composites. At the same time, particles may be agglomerated or too dispersed, which is not conducive to the formation of thermal conduction path, resulting in certain fluctuations in the thermal conductivity of composites under different conditions. Through the quantitative analysis of the two-dimensional stochastic model, the heat flux synergy, which can be used to describe the heat conduction network chain of composite materials, is obtained. The thermal conductivity of the composites can be determined by using the parameter value. Moreover, small particle size particles are easier to contact with each other to form a heat conduction network chain which is conducive to heat transfer. When the filling rate is the same and the square of particle size satisfies the normal distribution, the smaller the standard deviation is, the greater the thermal conductivity of the composites is. However, the thermal conductivity of the composite is the most stable when the standard deviation is 0.05. Therefore, the square standard deviation of particle size should be controlled between 0 and 0.05 in the case of optimal particle size. The experimental results of aluminum nitride ternary ethylene-propylene rubber are compared with the simulation results. It is found that the effect of interface on the thermal conductivity of composites can not be ignored. The modified three-phase Maxwell formula is obtained by modifying the Maxwell model, and the interface phase thickness can be deduced by the modified three-phase Maxwell model formula. It is found that the thin interface can improve the heat transfer efficiency to carbon nanotube, but the interfacial debonding is easy to occur by simulating the effect of interface on the thermal conductivity of ethylene-propylene rubber composites filled with carbon nanotube. The thick interface can increase the adhesion, but affect the heat transfer efficiency to carbon nanotubes. Therefore, the interface phase thickness should be controlled reasonably when optimizing the filled composites. Increasing the volume fraction and thermal conductivity of carbon nanotube composites can be realized by increasing the volume fraction of carbon nanotube and the thermal conductivity of interface phase.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332
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