无机纳米粒子的选择分布及其复合材料导热性能的研究

发布时间：2018-03-31 01:35

本文选题：氮化硼　切入点：氧化铝　出处：《哈尔滨理工大学》2015年硕士论文

【摘要】：因纳米粒子在改善聚合物力学性能和导热性能上的显著作用，导热聚合物基纳米复合材料的研究受到了广泛关注。本论文采用氮化硼(BN)、纳米氧化铝(Al2O3)为导热填料，以聚乙烯(PE)和乙烯-醋酸乙烯酯共聚物(EVA)为基体树脂，通过熔融共混法制备导热复合材料。论文在两相连续模型理论预测了PE/EVA共混物的相转变区域的基础上，利用溶剂选择萃取和扫描电子显微镜(SEM)研究了PE/EVA共混物的形貌结构，而获得了具有两相共连续结构的共混物，基于此，分别研究了BN、Al2O3在两相中的分布行为，评价了复合材料的导热性能和拉伸性能，，探讨了无机纳米粒子的选择分布行为与复合材料导热性能的关系。研究结果表明：(1) PE/EVA共混物的相结构与二者的用量比相关，根据两相共连续模型计算得到相转变点出现在PE的质量分数为51.8%附近，与实际实验结果相符，相结构研究表明在PE/EVA质量比为1/1时得到具有两相共连续结构的共混物；(2)无机粒子在两相共连续PE/EVA共混物中呈现出选择性分布行为，BN和Al2O3主要分布在PE相中，并与EVA相形成共连续结构；(3)无机纳米粒子的选择分布及其共连续结构有助于提高复合材料的导热性能，在BN质量分数为30%时，与PE/BN复合材料相比，具有选择分布和相连续结构的PE/EVA/BN复合材料的热导率提高了15.4%；在Al2O3质量分数为50%时，与PE/Al2O3复合材料相比，具有选择分布和相连续结构的PE/EVA/Al2O3复合材料的热导率提高了20.9%；(4)随着纳米粒子填充量的增加，PE/EVA/BN、PE/EVA/Al2O3复合材料的拉伸强度分别与PE/BN、PE/Al2O3复合材料相近，同时由于EVA相的增韧作用，断裂伸长率分别优于PE/BN复合材料与PE/Al2O3复合材料。
[Abstract]:Because of the remarkable effect of nano-particles on improving the mechanical and thermal conductivity of polymer, the research of thermal conductivity polymer matrix nanocomposites has been paid more and more attention.In this paper, the thermal conductivity composites were prepared by melt blending method using boron nitride (BNN), nano-alumina (Al _ 2O _ 3) as thermal conductive filler, polyethylene (PE) and vinyl acetate copolymer (EVA) as matrix resin.On the basis of predicting the phase transition region of PE/EVA blends based on two-phase continuum model theory, the morphology and structure of PE/EVA blends were studied by solvent selective extraction and scanning electron microscopy (SEM), and the blends with two-phase continuous structure were obtained.Based on this, the distribution behavior of BN- Al _ 2O _ 3 in two phases was studied, the thermal conductivity and tensile properties of the composites were evaluated, and the relationship between the selective distribution behavior of inorganic nanoparticles and the thermal conductivity of the composites was discussed.The results show that the phase structure of PE/EVA blends is related to their dosage ratio. According to the two-phase continuous model, the phase transition point appears in the range of 51.8% of PE, which is consistent with the experimental results.The study of phase structure shows that when the mass ratio of PE/EVA is 1 / 1, the blends with two-phase contiguous structure can be obtained. The inorganic particles exhibit selective distribution behavior in the two-phase continuous PE/EVA blends. BN and Al2O3 are mainly distributed in the PE phase.The selection and distribution of inorganic nanoparticles with EVA phase and their contiguous structure are helpful to improve the thermal conductivity of the composites. When the BN content is 30wt%, compared with the PE/BN composites,The thermal conductivity of PE/EVA/BN composites with selective distribution and phase continuous structure was increased by 15.40.When the mass fraction of Al2O3 was 50, the thermal conductivity of PE/Al2O3 composites was higher than that of PE/Al2O3 composites.The thermal conductivity of PE/EVA/Al2O3 composites with selective distribution and continuous phase structure increased by 20.90.The tensile strength of PEP / EVA- / EVA- Al _ 2O _ 3 composites was similar to that of PE- / BNN-PE-Al _ 2O _ 3 composites with the increase of the amount of nano-particles filled, and the toughening effect of EVA phase was also observed.The elongation at break is better than that of PE/BN and PE/Al2O3 respectively.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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