功能化石墨烯纳米片的制备、表征及应用

发布时间：2018-05-04 03:08

  本文选题：功能化石墨烯纳米片 + 磁搅拌研磨法　； 参考：《山东理工大学》2015年硕士论文

【摘要】：自从石墨烯被成功分离制备以来,一直是人们所研究的热点。本文对石墨烯的制备及应用进行了综述,提出了一种新颖、高效的制备石墨烯纳米片的方法,并在此基础上得到了功能化的石墨烯纳米片(Functionalized Graphene Nanoplatelets,FGNPs)。同时,论文也对FGNPs的改性和应用进行了论述,研究了其作为润滑油添加剂的润滑增效性能。论文的主要研究内容概括如下:功能化石墨烯纳米片的制备:以磁搅拌研磨法作为制备方法,通过弱磁性研磨介质的高速旋转所产生的摩擦力、碰撞力和剪切力将天然鳞片石墨以极高的效率破碎至纳米尺寸,随后又利用双氧水的氧化性将其功能化。采用氮气吸附、SEM、TEM、FTIR、TGA和XRD等手段进行了表征。结果表明,研磨时间为4h时即可得到比表面为738.1 m2 g-1的石墨烯纳米片,相对于原始石墨1.7 m2 g-1的比表面积增大了约434倍。FTIR结果显示样品表面具有羟基、羧基等含氧官能团。XRD和SAED显示出所制备样品具有良好的结晶性。功能化石墨烯纳米片的改性:利用功能化石墨烯纳米片存在的羟基、羧基等含氧官能团,以带有长链烷基的正十二烷基三乙氧基硅烷、硬脂酸、油酸等为改性剂,使FGNPs以化学键合的形式接枝长链烷基以改变其在润滑油中的悬浮稳定性。FTIR测试结果表明,改性后的石墨烯纳米片具有对称亚甲基和不对称甲基峰出现。当改性石墨烯纳米片(Modified Graphene Nanoplatelets,MFGNPs)与未改性石墨烯纳米片分散液相比较时,在相同的离心速度和时间下前者有着更高的吸光度值,表明其具有更好的悬浮稳定性。改性石墨烯纳米片的摩擦学性能测试:利用改性石墨烯纳米片的小尺寸和自润滑特点,作为添加剂添加到润滑油中以增强润滑油的润滑效果。四球摩擦实验表明,相比较基础油而言,当MGNPs添加量为1 wt‰时,平均摩擦系数从0.1170降低到0.0642,磨斑大小从482μm降低到353μm,分别降低了约45%和26.8%。当添加量增加到1.5 wt‰时,平均摩擦系数和磨斑直径分别为0.0282、284μm,较之基础油分别降低了75.9%和41.1%。这充分说明了改性石墨烯纳米片在保证其良好的悬浮稳定性的基础上有着优秀的润滑增效功能。此外,本实验制备功能化石墨烯纳米片所采用的磁搅拌研磨法是一种高效、环保、低成本的物理破碎法,可实现石墨烯纳米片的大规模制备。本论文对功能化石墨烯纳米片的制备效率也进行了一定的探究。
[Abstract]:Since the successful separation and preparation of graphene, it has been a hot topic. In this paper, the preparation and application of graphene are reviewed, and a novel and efficient method for preparing graphene nanoparticles is proposed. On the basis of this, Functionalized Graphene Nanoplatelets (FGNPs) are obtained. At the same time, the modification and application of FGNPs were discussed, and its lubricating and synergistic properties were studied. The main research contents of this paper are summarized as follows: preparation of functional graphene nanoparticles: friction produced by high speed rotation of weak magnetic grinding medium by magnetic agitation grinding method. The natural flake graphite was crushed to nanometer size by impact force and shear force with high efficiency, and then functionalized by the oxidation of hydrogen peroxide. The structure was characterized by nitrogen adsorption, TGA and XRD. The results showed that graphene nanoparticles with a specific surface area of 738.1 m ~ 2 g ~ (-1) were obtained when grinding time was 4 h, and the specific surface area of the sample was increased by about 434-fold compared with that of the original graphite (1.7m ~ (2) g ~ (-1). The results showed that the surface of the sample had hydroxyl groups. The oxygen functional groups such as carboxyl group. XRD and SAED show that the prepared samples have good crystallinity. Modification of functionalized graphene nanoparticles: using hydroxyl, carboxyl and other oxygen-containing functional groups in functionalized graphene nanoparticles, using n-dodecyl triethoxy silane, stearic acid, oleic acid and so on with long chain alkyl as modifier, FGNPs was grafted with long chain alkyl in the form of chemical bonding to change its suspension stability in lubricating oil. FTIR results showed that the modified graphene nanoparticles had symmetrical methylene and asymmetric methyl peaks. When modified Graphene Nanoplatelets (MFGNPs) is compared with unmodified graphene nanoparticles, the former has higher absorbance at the same centrifugal rate and time, which indicates that the modified graphene has better suspension stability. The tribological properties of the modified graphene nanoparticles were tested. The small size and self-lubricating characteristics of the modified graphene nanoparticles were used as additives to enhance the lubricating effect of the lubricating oil. The four-ball friction experiment shows that the average friction coefficient decreases from 0.1170 to 0.0642 and the wear spot size decreases from 482 渭 m to 353 渭 m when the content of MGNPs is 1 wt 鈥，

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