RGO的制备及其对PMMA/RGO复合材料介电性能的影响

Preparation of Reduced Graphene Oxide and Its Effectiveness to Dielectric Properties of PMMA

以氧化还原法为基础制备了两种非改性的还原氧化石墨烯(RGO):水合肼还原制备的RGO(RGO–N)和水合肼还原后真空退火制备的RGO(RGO–V),之后以这两种RGO和聚甲基丙烯酸甲酯(PMMA)为原料通过简单溶液复合法制备了PMMA/RGO复合材料。通过透射电子显微镜、原子力显微镜和X射线光电子能谱对两种RGO的形貌和结构进行了表征。结果表明,这两种RGO都为单层或少数几层的片状结构,其中RGO–V的导电性高于RGO–N,且其厚度低于RGO–N。通过扫描电子显微镜对PMMA/RGO复合材料的断面形貌进行了表征,发现RGO能均匀地分散在PMMA中并且与PMMA有明显的界面相互作用。进一步研究了不同RGO含量下制备的PMMA/RGO复合材料介电性能的变化。结果表明,两种RGO均能提高复合材料的介电常数;且随着RGO含量的增加,复合材料的介电常数明显增大,而介电损耗变化不大。在室温及1 000 Hz下,当RGO–V体积分数为2.75%时,PMMA/RGO–V复合材料的介电常数为20.5,是纯PMMA的的5倍,是相同RGO含量下PMMA/RGO–N复合材料的2.5倍,而介电损耗仅为0.80。

Two kinds of non-modified reduced graphene oxide （RGO） based on oxidation-reduction method：RGO-N only reduced by hydrazine hydrate and RGO-V reduced by hydrazine hydrate plus annealing in vacuum. Then poly（methyl methacrylate） （PMMA） / RGO composites were fabricated with a simple solution blending methods by using this two kinds of RGO and PMMA. The morphologies and structures of the two kinds of RGO were characterized by TEM, AFM and XPS. The results show that the two kinds of RGO all consist of single layer or few layers graphene, the conductivity of RGOV is higher than that of RGO-N and the thickness of RGO-V is thinner than that of RGO-N. The fracture appearances of the PMMA/RGO composites were investigated by SEM and it was found that the two kinds of RGO can disperse well in PMMA matrix and behave evident interaction with PMMA. The dielectric properties of PMMA / RGO composites with different RGO content were further studied. The results indicate that the two kinds of RGO can both improve the dielectric constant of the composites. With increasement of R GO content, the dielectric constant become higher and the dielectric loss is still low. At 1 000 Hz and room temperature, when the volume fraction of RGO-V is 2.75%, the dielectric constant of PMMA/RGO-V composite is 20.5, which is 5 times higher than that of pure PMMA and 2.5 times higher than that of PMMA/RGO-N composite with same RGO-N content, and the dielectric loss is only 0.80.