功能化石墨烯及其复合材料的制备与性能研究

发布时间：2019-06-06 03:56

【摘要】：石墨烯是由碳原子以正六边形组成的蜂窝状单层二维片层材料,具有优异的电学性能、光学性能、热导性能、阻隔性能、量子霍尔效应、室温铁磁效应等,已经成为当前研究的热点。目前制备石墨烯的方法有很多,大多都条件苛刻难以实现,氧化还原法制备石墨烯具有操作简单、成本低廉、产率高以及可大规模生产等优点而被广泛使用。无论是氧化石墨烯还是石墨烯都具有优异综合性能和超高比表面积,因此使它们成为制备高性能复合材料的理想填料。但是石墨烯在基体体系中分散和团聚是限制其广泛应用的关键问题。本论文为解决这些问题,从提高填料与基体之间界面的相互作用出发,在石墨烯的表面引入活性官能团,并用这些功能化的石墨烯作为填料制备聚合物复合材料。主要研究内容如下:(1)通过氧化还原法制备氧化石墨烯和石墨烯,再利用其表面的含氧基团(羟基、羧基、羰基、环氧基)进行共价键修饰。首先是氨基化修饰,用对苯二胺溶液和氧化石墨烯溶液按10:1(固含量比)混合,90℃反应24h,然后还原离心分离,得到氨基功能化石墨烯;其次用接枝法在氨基化石墨烯表面接上磁性纳米粒子得到磁功能化石墨烯;以上两种功能化石墨烯都可在有机溶剂中重新分散。(2)通过机械共混的方法制备氨基功能化石墨烯硅橡胶复合材料。利用氨基化石墨烯可重新分散在有机溶剂中的特点,将其与室温硫化硅橡胶(RTV-Silicone Rubber)在四氢呋喃(THF)中混合制备复合材料。石墨烯的加入大大提升了硅橡胶力学强度、热稳定性能、电性能和气体阻隔性能,由于氨基的引入,使石墨烯与硅橡胶之间有了很好的结合作用,当填料含量为0.5%时,拉伸强度和断裂伸长率分别提升164.7%、122.6%;当填料含量为1.5%时,热稳定性大幅度提升,热分解起始温度较硅橡胶提升10~16℃,到600℃时失重率只降低了14%;当填料含量为1%时使硅橡胶体积电阻从1016?降低到107?,降低9个数量级。功能化石墨烯的加入也使体系的气体阻隔性能提升,填料含量为0.7%时,透气系数减小为RTV硅橡胶的2/3,即阻隔性能在硅橡胶的基础上提升了33.3%。(3)通过溶液共混法制备氨基功能化石墨烯聚乳酸复合材料和磁性石墨烯聚乳酸复合材料。用XRD、SEM、DSC表征了复合材料的结构形貌和分散情况,也研究了复合材料的热稳定性能、电性能和气体阻隔性能。XRD和SEM分析表明,功能化石墨烯在聚乳酸体系中分散性较好,没有出现团聚现象,功能化石墨烯片被聚乳酸分子链包覆,相界面模糊;复合材料形貌粗糙,纯聚乳酸形貌光滑平整;DSC分析表明,聚乳酸复合材料的玻璃化转变温度随着功能化石墨烯的加入量增多依次升高,纯聚乳酸的Tg为56.2℃,当功能化石墨烯含量为0.5%时,Tg达到62.4℃;电性能和透气性能分析表明,纯聚乳酸的电导率在10~(-17)S·m~(-1)附近,随着功能化石墨烯的加入,电导率开始逐渐上升。当填料含量为0.1%时,电导率达到了10~(-13)S·m~(-1),含量为2%时,电导率为10~(-8)S·m~(-1),较聚乳酸提升了9个数量级。当填料含量为0.03%时,透气系数减小到2.42×10~(-12) cm~(3)·cm/cm~(2)·s·Pa。(4)为深入研究填料在基体体系中的分散情况,初步建立了聚合物大分子链群带取向模型和二维石墨烯在聚合物中取向角测定模型。
[Abstract]:Graphene is a cellular single-layer two-dimensional sheet material consisting of carbon atoms in a regular hexagon, and has excellent electrical properties, optical properties, thermal conductivity properties, barrier properties, quantum Hall effect, room temperature iron magnetic effect, and the like, and has become the hot spot of the current research. At present, the method for preparing the graphene has many advantages, most of which are difficult to realize, and the preparation of the graphene by the oxidation reduction method has the advantages of simple operation, low cost, high yield and large-scale production and the like. Both the graphene oxide and the graphene have excellent comprehensive performance and super-high specific surface area, so that the graphene oxide and the graphene are the ideal filler for preparing the high-performance composite material. However, that dispersion and agglomeration of the graphene in the matrix system is a key problem to limit the wide application of the graphene. In order to solve these problems, the active functional group is introduced into the surface of the graphene from the interaction of the interface between the filler and the matrix, and the functionalized graphene is used as a filler to prepare the polymer composite material. The main contents of the study are as follows: (1) The graphene oxide and the graphene are prepared by the oxidation reduction method, and the oxygen-containing group (hydroxyl group, the base group, the phenyl group and the epoxy group) on the surface of the graphene are used for covalent bonding modification. firstly, amination modification is carried out, the p-phenylenediamine solution and the graphene oxide solution are mixed according to a ratio of 10:1 (solid content ratio), the reaction is carried out at 90 DEG C for 24 hours, and then the centrifugal separation is carried out to obtain the amino-functionalized graphene; Secondly, the magnetic nano particles are connected with the surface of the aminated graphene by a grafting method to obtain the magnetic functionalized graphene; and the two functional graphene can be re-dispersed in the organic solvent. And (2) preparing the amino-functional graphene silicon rubber composite material by a mechanical blending method. The characteristics of the re-dispersion of the aminated graphene in the organic solvent were redispersed, and the composite was prepared by mixing it with room temperature vulcanized silicone rubber (RTV-Silicone Rubber) in tetrahydrogen peroxide (THF). the addition of the graphene greatly improves the mechanical strength, the thermal stability, the electrical property and the gas barrier performance of the silicon rubber, The tensile strength and the elongation at break are respectively increased by 164.7% and 122.6%, when the content of the filler is 1.5%, the thermal stability is greatly improved, the initial temperature of the thermal decomposition is increased by 10-16 DEG C from the silicone rubber, and the weight loss rate is only reduced by 14% when the content of the filler is 1%; and when the content of the filler is 1%, the volume resistance of the silicon rubber is increased from 1016? Down to 107? And is reduced by 9 orders of magnitude. The addition of the functionalized graphene also improves the gas barrier performance of the system, and when the content of the filler is 0.7%, the air permeability coefficient is reduced to 2/3 of the RTV silicone rubber, that is, the barrier property is improved by 33.3% on the basis of the silicon rubber. And (3) preparing the amino-functional graphene polylactic acid composite material and the magnetic graphene polylactic acid composite material by a solution blending method. The structure and dispersion of the composites were characterized by XRD, SEM and DSC. The thermal stability, electrical property and gas barrier properties of the composites were also studied. The results of XRD and SEM show that the dispersion of the functionalized graphene in the polylactic acid system is good, no agglomeration phenomenon occurs, the functionalized graphene sheet is coated by the polylactic acid molecule chain, the phase interface is fuzzy, the morphology of the composite material is rough, the appearance of the pure polylactic acid is smooth and flat, and the DSC analysis shows that, the glass transition temperature of the polylactic acid composite material is increased in sequence with the addition of the functionalized graphene, the Tg of the pure polylactic acid is 56.2 DEG C, when the content of the functionalized graphene is 0.5 percent, the Tg is up to 62.4 DEG C, and the electrical property and the air permeability can be analyzed, The conductivity of the pure polylactic acid is about 10 ~ (-17) S 路 m ~ (-1), and with the addition of the functionalized graphene, the conductivity starts to increase gradually. When the content of the filler is 0.1%, the conductivity is 10 ~ (-13) S 路 m ~ (-1), the content is 2%, the conductivity is 10 ~ (-8) S 路 m ~ (-1), and the polylactic acid is increased by 9 orders of magnitude. When the content of the filler is 0.03%, the air permeability coefficient is reduced to 2.42-10-(-12) cm-(3) 路 cm/ cm-(2) 路 s 路 Pa. (4) In order to study the dispersion of the filler in the matrix system, the orientation model and the orientation angle measurement model of the two-dimensional graphene in the polymer are preliminarily established.
【学位授予单位】：上海工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O613.71;TB33

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