本文選題：石墨烯 + 氮化硼納米片��； 參考：《安徽理工大學》2017年碩士論文

【摘要】：石墨烯作為先進二維材料,具有很好的物理化學性能。由于其比表面積大,機械伸縮性良好,導(dǎo)熱性高,在新材料領(lǐng)域引起了越來越多的關(guān)注。六方氮化硼納米片(BNNS),與石墨烯具有相似的結(jié)構(gòu)。石墨烯導(dǎo)熱性能優(yōu)越且導(dǎo)電性能好,而BNNS卻是很好的電絕緣材料,介電常數(shù)為2-4.8。在電子封裝和高功率電子學中的熱傳遞耗散材料中的應(yīng)用前景廣闊,但通過六方氮化硼(h-BN剝離制備BNNS存在各種各樣的問題。本論文主要包括三個方面:(1)石墨烯厚度對相應(yīng)的石墨烯薄膜的導(dǎo)熱性能和介電性能的影響;(2)發(fā)明了以熔融堿機械剝離氮化硼納米片(BNNS)的方法,并制備了出上下兩層為石墨烯納米片,中間為BNNS的三明治復(fù)合材料薄膜。并研究對比了三明治薄膜與石墨烯薄膜的導(dǎo)熱性能的差異;(3)采用抽濾方法制備了獨立的BNNS薄膜,并研究了 BNNS在高分子材料聚酰亞胺中的應(yīng)用。研究表明:(1)厚度越大的石墨烯納米片對應(yīng)的石墨烯薄膜水平方熱傳導(dǎo)能力越高和導(dǎo)電能力越強。厚度為7 nm的GNP-7薄膜的導(dǎo)熱系數(shù)高達149.2 W/mK,約為GNP-3(厚度為3 nm)和GNP-5(厚度為5 nm)的7倍。此外,GNP-7冷壓后導(dǎo)熱系數(shù)又提高了 25%到187.4 W/mK;(2)研究了一種利用熔融堿和超聲剝離技術(shù)制備六方氮化硼納米片的方法,這種BNNS剝離方法不僅工藝簡單、處理原料廉價易得、對設(shè)備要求低、對環(huán)境毒性小、且便于大規(guī)模生產(chǎn),可大大降低產(chǎn)品成本,而且產(chǎn)率高達19%,高于迄今為止所報道的大多數(shù)液相剝離方法。同時剝離制備的BNNS的粒徑為0.5-2.5 um,厚度為0.5-7 nm,且表面修飾有羥基。同時采用簡單的真空抽濾方法,制備了石墨烯-氮化硼納米片-石墨烯(G-BNNS-G)的三明治薄膜。通過對其導(dǎo)熱性能分析,G-BNNS-G薄膜在水平方向?qū)嵯禂?shù)達53.09 W/mK,較GNP-3薄膜(21.5 W/mK)高;(3)獨立的BNNS薄膜在水平方向?qū)嵯禂?shù)高達58 W/mK,聚酰亞胺(PI)中加入7 wt%的BNNS時,BNNS/PI復(fù)合材料垂直方向的導(dǎo)熱系數(shù)為0.441 W/mK而水平方向的導(dǎo)熱系數(shù)達到2.946 W/mK,與純PI薄膜相比,水平方向?qū)嵯禂?shù)增加了1078%,但垂直方向僅增加76%,具有明顯的各向異性。
[Abstract]:As an advanced two-dimensional material, graphene has good physical and chemical properties. Because of its large specific surface area, good mechanical scalability and high thermal conductivity, it has attracted more and more attention in the field of new materials. The structure of hexagonal boron nitride nanocrystalline (BNNSN) is similar to that of graphene. Graphene has excellent thermal conductivity and good conductivity, but BNNS is a good electrical insulating material with a dielectric constant of 2-4.8. The applications in electronic packaging and high power electronics heat transfer dissipative materials are promising, but there are various problems in the preparation of BNNS by hexagonal boron nitride h-BN peeling. This thesis mainly includes three aspects: the influence of the thickness of graphene on the thermal conductivity and dielectric properties of the corresponding graphene thin films. The method of mechanical stripping of boron nitride nanocrystalline (BNNSs) with molten alkali was invented in this paper. A sandwich composite film with two layers of graphene nanocrystalline and BNNS in the middle was prepared. The difference of thermal conductivity between sandwich film and graphene film was compared. The independent BNNS thin film was prepared by filtration method and the application of BNNS in polymer polyimide was studied. The results show that the higher the thickness of graphene nanocrystals, the higher the horizontal thermal conductivity and conductivity of graphene films. The thermal conductivity of GNP-7 thin films with thickness of 7 nm is as high as 149.2 W / mK, which is about 7 times that of GNP-3 (thickness of 3 nm) and GNP-5 (thickness of 5 nm). In addition, the thermal conductivity of GNP-7 has been increased by 25% to 187.4 W / mKK ~ (2) after cold pressing. A method of preparing hexagonal boron nitride nanocrystals using molten alkali and ultrasonic stripping technology has been studied. This BNNS stripping method is not only simple in process, but also cheap in processing raw materials. Because of its low requirements for equipment, low toxicity to the environment, and convenient for mass production, the cost of the product can be greatly reduced, and the yield is as high as 19 percent, which is higher than most liquid stripping methods reported so far. The diameter and thickness of the BNNS were 0.5-2.5 um. the thickness was 0.5-7 nm, and the surface was modified with hydroxyl groups. At the same time, the sandwich films of graphene-boron nitride nanocrystalline-graphene G-BNNS-G were prepared by a simple vacuum filtration method. Thermal conductivity analysis of G-BNNS-G thin films with horizontal thermal conductivity of 53.09 W / mK, 21.5 W / mK higher than that of GNP-3 thin films.) the horizontal thermal conductivity of BNNS films is as high as 58 W / mK, and 7 wt% BNNS is added to the BNNS films. The thermal conductivity in the vertical direction is 0.441 W/mK, and the thermal conductivity in the horizontal direction is 2.946 W / mK. compared with the pure Pi film, The thermal conductivity in the horizontal direction increases by 1078, but in the vertical direction only increases by 76, with obvious anisotropy.
【學位授予單位】：安徽理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB383.2

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