石墨烯对碳纤维表面修饰及其水泥基复合材料性能研究

发布时间：2018-08-08 19:41

【摘要】：随着电磁辐射日趋严重,既能大面积进行电磁防护,又能避免和阻止电磁波形式的间谍和窃听活动的水泥基电磁屏蔽材料受到关注。基于优异的导电性能,碳纤维(CF)作为电磁屏蔽复合材料的功能填料受到青睐。本文利用具有良好亲水性能的氧化石墨烯(GO)和Fe3O4磁性粒子对CF进行表面修饰处理,在使CF均匀分散于水泥基体中,且与基体界面结合良好的同时,达到提高水泥基复合材料电磁屏蔽性能的目的。首先研究了GO对水泥基复合材料的微观结构及其宏观性能的影响,采用XRD和SEM等表征方法,分析GO对水泥基复合材料的水化反应作用机理。GO的加入使水泥水化生成了形状规整、体积微小的花朵状产物,但没有改变水化产物的种类。水泥石结构密实,孔径较小,说明GO对水泥水化反应产物的形成具有促进和模板效应,有利于形成致密水泥石,有助于提高水泥的力学性能。宏观性能分析表明,GO的掺入能提高水泥试样的早期强度。当GO添加量为0.08wt.%时,水泥试样的电磁屏蔽效能较高,其主要贡献为提高了水泥的电磁屏蔽吸收效能。对GO修饰CF(GO-CF)水泥基复合材料的微观结构和宏观性能进行了研究。通过SEM等表征方法,分析GO对CF与水泥基体界面结合的影响。结果表明,修饰在CF表面的GO也能实现对水泥水化的微观调控,在GO-CF表面以GO为模板生长着多种水化产物,从而加固了CF与水泥基体的界面结合。当GO-CF的掺量达0.4wt.%时,电磁屏蔽效能达到34dB。通过离心-溶解法对GO进行分离,得到了两种尺寸的GO片层。对比大片层GO和小片层GO修饰CF/水泥的电磁屏蔽性能,大片层GO修饰CF对水泥基复合材料性能的提高有较好的作用,最大电磁屏蔽效能达36dB。使用NaBH4对CF表面的GO进行原位还原(RGO),RGO修饰CF(RGO-CF)/水泥的宏观性能测试结果表明,RGO-CF/水泥力学性能和电磁屏蔽效能均介于未处理CF/水泥复合材料与GO-CF/水泥复合材料之间。将GO与Fe3O4同时分散于去离子水中,以此作为电镀液,对CF进行电泳沉积,得到GO包裹Fe3O4修饰碳纤维(GOFe3O4-CF),对其水泥基复合材料的性能进行研究,结果表明GO和Fe3O4能够均匀而牢固地包裹在CF表面,GOFe3O4-CF与水泥的界面结合良好。电磁屏蔽性能测试显示,磁性材料的加入提高了复合材料的电磁屏蔽效能,当GOFe3O4-CF的掺量达0.4wt.%时,复合材料的电磁屏蔽效能达到36dB。
[Abstract]:As electromagnetic radiation becomes more and more serious, cement-based electromagnetic shielding materials, which can not only protect large areas, but also prevent and prevent the form of electromagnetic wave espionage and eavesdropping activities, have attracted much attention. Based on the excellent electrical conductivity, carbon fiber (CF) is favored as the functional filler of electromagnetic shielding composites. In this paper, (GO) and Fe3O4 magnetic particles of graphene oxide with good hydrophilicity were used to modify the surface of CF. The CF was uniformly dispersed in the cement matrix and bonded well with the matrix interface. To improve the electromagnetic shielding performance of cement-based composites. The effect of go on the microstructure and macroscopic properties of cement matrix composites was studied. The hydration reaction mechanism of cement matrix composites was analyzed by XRD and SEM, and the shape of cement hydration was formed by the addition of go. Tiny flower-like product, but not changing the type of hydration product. The cement stone has dense structure and small pore diameter, which indicates that go can promote the formation of cement hydration reaction product and form template, which is beneficial to the formation of dense cement stone and helps to improve the mechanical properties of cement. The macroscopical property analysis shows that the incorporation of go can improve the early strength of cement samples. When the content of go is 0.08wt.%, the electromagnetic shielding efficiency of cement sample is higher, and its main contribution is to improve the absorption efficiency of cement electromagnetic shielding. The microstructure and macroscopic properties of go modified CF (GO-CF) cement matrix composites were studied. The effect of go on the interface bonding between CF and cement matrix was analyzed by means of SEM and other characterization methods. The results show that go modified on CF surface can also achieve micro-control of cement hydration. On the surface of GO-CF, a variety of hydration products are grown using go as template, thus strengthening the interface between CF and cement-based body. When the content of GO-CF reaches 0.4wt.%, the electromagnetic shielding efficiency reaches 34dB. Go was separated by centrifugal-dissolution method and two kinds of go layers were obtained. Compared with the electromagnetic shielding properties of CF/ cement modified by large layer go and small lamellar go, the large layer go modified CF has a better effect on the improvement of cement matrix composite properties, and the maximum electromagnetic shielding efficiency is 36 dB. The macroscopic properties of CF (RGO-CF) / cement modified by (RGO) / cement modified by in situ reduction of go on CF surface by NaBH4 were measured. The results show that the mechanical properties and electromagnetic shielding efficiency of RGO-CFC / cement are between untreated CF/ cement composites and GO-CF/ cement composites. Go and Fe3O4 were dispersed in deionized water at the same time, which was used as electroplating solution to electrophoretic deposition of CF. Go coated Fe3O4 modified carbon fiber (GOFe3O4-CF) was obtained. The properties of Fe3O4 modified carbon fiber (GOFe3O4-CF) were studied. The results show that go and Fe3O4 can be wrapped uniformly and firmly on the surface of CF and the interface between gofe _ 3O _ 4-CF and cement is good. The electromagnetic shielding performance test shows that the electromagnetic shielding efficiency of the composite is improved with the addition of magnetic material. When the content of GOFe3O4-CF reaches 0.4 wt.%, the electromagnetic shielding efficiency of the composite reaches 36 dB.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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