Roy Sunanda, Tang Xiuzhi, Das Tanya, Zhang Liying, Li Yongmei, Ting Sun, Hu Xiao, Yue C Y
School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798.
ACS Appl Mater Interfaces. 2015 Feb 11;7(5):3142-51. doi: 10.1021/am5074408. Epub 2015 Jan 30.
Development of advanced graphene based polymer composites is still confronted with severe challenges due to its poor dispersion caused by restacking, weak interface bonding, and incompatibility with polymer matrices which suppress exertion of the actual potential of graphene sheets in composites. Here, we have demonstrated an efficient chemical modification process with polyethylenimine (PEI) to functionalize graphene oxide which can overcome the above-mentioned drawbacks and also can remarkably increase the overall strength of the nylon 12 composites even at very low graphene loading. Chemical modification was analyzed by various surface characterizations including X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Addition of only 0.25 and 0.35 wt % modified GO showed 37% and 54% improvement in tensile strength and 65% and 74% in Young's modulus, respectively, compared with that of the neat polymer. The dynamic mechanical analysis showed ∼39% and 63% increment in storage modulus of the nanocomposites. Moreover, the nanocomposites exhibited significantly high thermal stability (∼15 °C increment by only 0.35 wt %) as compared to neat polymer. Furthermore, the composites rendered outstanding resistance against various chemicals.
由于石墨烯片层的重新堆叠导致分散性差、界面结合力弱以及与聚合物基体不相容，抑制了石墨烯片层在复合材料中实际潜力的发挥，先进的基于石墨烯的聚合物复合材料的开发仍面临严峻挑战。在此，我们展示了一种用聚乙烯亚胺（PEI）对氧化石墨烯进行功能化的有效化学改性过程，该过程可以克服上述缺点，并且即使在极低的石墨烯负载量下也能显著提高尼龙12复合材料的整体强度。通过包括X射线光电子能谱、傅里叶变换红外光谱和X射线衍射在内的各种表面表征对化学改性进行了分析。与纯聚合物相比，仅添加0.25 wt%和0.35 wt%的改性氧化石墨烯，拉伸强度分别提高了37%和54%，杨氏模量分别提高了65%和74%。动态力学分析表明，纳米复合材料的储能模量提高了约39%和63%。此外，与纯聚合物相比，纳米复合材料表现出显著高的热稳定性（仅0.35 wt%就使热稳定性提高了约15℃）。此外，该复合材料对各种化学物质具有出色的抗性。
