聚甲基丙烯酸甲酯/石墨薄片纳米复合及其导电性能研究

在聚合物绝缘材料基体中添加入足够数量的导电填料 ,聚合物便具有导电性或半导体性能 .石墨材料 ,由于资源丰富、价廉、性质稳定 ,被广泛用作导电聚合物复合材料的填料 .一般 ,填料含量越高 ,复合材料的导电性能越好 ,但是材料的力学性能也随之劣化 ,特别是材料脆性增加 .将石墨加工成纳米级粒子 ,再与聚合物纳米复合 ,有望用较少的石墨填充量使复合材料具有良好的电传导性能 ,从而保持材料的力学性能 .最近报道的利用膨胀石墨与聚合物实现纳米复合的研究引起了人们的兴趣 ,如所报道的尼龙 6 膨胀石墨1] 、PS PMMA 膨胀石墨2 ] 、PP …

INVESTIGATION ON THE PMMA/GRAPHITE PLATELET NANOCOMPOSITES AND THEIR CONDUCTION PROPERTIES

A preparation process of PMMA/graphite nanocomposites was developed via in situ polymerization of monomers in the presence of sonicated expanded graphite with the aid of sonication.Expanded graphite was sonicated in a 70% aqueous alcohol solution to get graphite platelets (NanoG) with thickness of 30～80 nm and diameter of 0.5～20 μm.The NanoG were dispersed in MMA monomers with BPO initiator.In situ polymerization was taken place when the mixture was heated under sonication.The TEM studies showed that the graphite nano-platelets were well dispersed in the PMMA matrix.Solution cast films of the nanocomposite were used for electrical conductivity measurements.The percolation threshold of polymer/NanoG nanocomposite films at room temperature was lower than 1.0 wt%,which was much lower than that of the composites with conventional graphite filler which was 5.5 wt%.The electrical conductivity reached 10 -3 S/cm at a graphite content of about 4.0 wt%.The special structure of graphite nano- platelets with high aspect ratio of as high as 100～500 (width-to-thickness) played an important role in forming a conducting network within the PMMA matrix.