【摘要】：隨著科技的飛速發(fā)展,導(dǎo)熱高分子的應(yīng)用越來越廣泛,已經(jīng)成為目前學(xué)者們研究的熱點。本文實驗制備了氮化鋁填充三元乙丙橡膠復(fù)合材料,熱探針法測量了其在不同填充分?jǐn)?shù)下的導(dǎo)熱性能并利用3D測量激光顯微鏡對其表面進(jìn)行了觀察。利用ANSYS有限元分析軟件模擬了填料粒子的空間分布、粒徑大小、粒徑正態(tài)分布、界面相特性對橡膠復(fù)合材料導(dǎo)熱性能的影響。同時,對單一球徑填充時的空間量化分析及帶有界面相模型的氮化鋁三元乙丙橡膠復(fù)合材料進(jìn)行了量化分析。研究表明：隨著氮化鋁填充量的增加,復(fù)合材料導(dǎo)熱性能呈現(xiàn)線性增加趨勢,填充氮化鋁可以極大提高復(fù)合材料的導(dǎo)熱性能。由于制備的復(fù)合材料中反光物質(zhì)較多,利用3D測量激光顯微鏡很難直接觀測到復(fù)合材料中氮化鋁的分布情況。在填充單一粒徑的粒子時,粒子在橡膠中的分布對復(fù)合材料導(dǎo)熱性能的影響較大。填料粒子在基體中的多選擇性可能形成分布較好的導(dǎo)熱通路,極大的提高復(fù)合材料的導(dǎo)熱性能。同時粒子也可能發(fā)生團(tuán)聚或過于分散,不利于導(dǎo)熱通路的形成,從而造成不同情況下復(fù)合材料的導(dǎo)熱性能出現(xiàn)一定波動性。通過對二維隨機(jī)模型的量化分析,得到了可以描述復(fù)合材料導(dǎo)熱網(wǎng)鏈的參數(shù)——熱流協(xié)同度。利用此參數(shù)值的大小可以判定復(fù)合材料導(dǎo)熱性能的大小。而且小粒徑粒子之間更容易相互接觸形成有利于熱量傳遞的導(dǎo)熱網(wǎng)鏈。在填料填充率相同,粒徑的平方滿足正態(tài)分布時,標(biāo)準(zhǔn)差越小復(fù)合材料導(dǎo)熱性能越大。但標(biāo)準(zhǔn)差為0.05時復(fù)合材料導(dǎo)熱性能最為穩(wěn)定。因此,粒徑最優(yōu)的情況應(yīng)該控制粒徑的平方標(biāo)準(zhǔn)差在0～0.05之間。氮化鋁三元乙丙橡膠的實驗值與模擬結(jié)果對比發(fā)現(xiàn)界面相對復(fù)合材料導(dǎo)熱性能的影響不可忽略。我們對Maxwell模型進(jìn)行修正得到了修正后三相Maxwell公式,同時通過修正的三相Maxwell模型公式可以反推出界面相厚度。通過模擬界面相對碳納米管填充三元乙丙橡膠復(fù)合材料導(dǎo)熱性能的影響發(fā)現(xiàn)：薄界面可以提高熱量向碳納米管的傳輸效率,但容易發(fā)生界面脫粘。厚界面可以增加粘結(jié)性,但影響了熱量向碳納米管的傳輸效率。因此在優(yōu)化填充型復(fù)合材料時應(yīng)該合理控制界面相厚度。提高碳納米管復(fù)合材料時可以增加碳納米管體積分?jǐn)?shù)和界面相導(dǎo)熱性能來實現(xiàn)。
[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.
【學(xué)位授予單位】：青島科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB332

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本文編號：2484601