Zhang Jifei, Zuo Min, Lv Xiong, Zhang Haimo, Zheng Qiang
MOE Key Laboratory of Macromolecule Synthesis and Functionalization, Ministry of Education, Department of Polymer Science and Engineering, Zhejiang University Hangzhou 310027 China
RSC Adv. 2018 Apr 18;8(26):14579-14588. doi: 10.1039/c8ra00439k. eCollection 2018 Apr 17.
A facile method was developed for directly grafting poly(methyl methacrylate) (PMMA) to graphene oxide (GO) without surface modification, with the resultant insulating PMMA--GO nanosheets further reduced to give conductive grafted reduced graphene oxide (RGO) nanosheets. The effect of PMMA--RGO nanosheets on the morphological evolution and conductive behavior of partially miscible blends of poly(methyl methacrylate)/poly (styrene--acrylonitrile) (PMMA/SAN) upon annealing above their phase-separation temperature was investigated using phase-contrast microscopy (PCM) with a real-time online digital picoammeter. With phase separation of the blend matrix, the well-dispersed PMMA--RGO nanosheets in the homogeneous matrix preferentially migrated to the SAN-rich phase and showed remarkably little aggregation. Surface grafting of PMMA--RGO might inhibit the aggregation of nanosheets in the blend matrix and weaken the retardation effect of nanosheets on the morphology evolution of the blend matrix. Furthermore, the percolation behavior of dynamic resistivity for ternary nanocomposites was attributed to the formation of a PMMA--RGO conductive network in the SAN-rich phase. The activation energy of conductive pathway formation was closer to the activation energy of flow for PMMA than that of SAN.
开发了一种无需表面改性即可将聚甲基丙烯酸甲酯（PMMA）直接接枝到氧化石墨烯（GO）上的简便方法，所得绝缘的PMMA - GO纳米片进一步还原以得到导电的接枝还原氧化石墨烯（RGO）纳米片。使用带有实时在线数字皮安计的相差显微镜（PCM）研究了PMMA - RGO纳米片在高于其相分离温度退火时对聚甲基丙烯酸甲酯/聚（苯乙烯 - 丙烯腈）（PMMA / SAN）部分互溶共混物的形态演变和导电行为的影响。随着共混物基体的相分离，均匀基体中分散良好的PMMA - RGO纳米片优先迁移到富含SAN的相中，并且几乎没有明显聚集。PMMA - RGO的表面接枝可能抑制了纳米片在共混物基体中的聚集，并减弱了纳米片对共混物基体形态演变的阻滞作用。此外，三元纳米复合材料动态电阻率的渗流行为归因于在富含SAN的相中形成了PMMA - RGO导电网络。导电通路形成的活化能比SAN更接近PMMA的流动活化能。
