Preparation of Solution-Processable Reduced Graphene Oxide/Polybenzoxazole Nanocomposites with Improved Dielectric Properties
Preparation of Solution-Processable Reduced Graphene Oxide/Polybenzoxazole Nanocomposites with Improved Dielectric Properties
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DOI：
10.1021/ma502326v
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发表时间：
2015-01-27
期刊：
影响因子：
5.5
通讯作者：
Han, Zhewen
中科院分区：
文献类型：
--
作者：
Chen, Yi;Zhang, Shuo;Han, Zhewen
提高聚合物基体中偶极子的取向自由度，增强导电填料在基体中的均匀分散，是制备高介电常数、低介电损耗、低密度、加工性能好的复合材料的关键。与传统的主链型聚苯并恶唑相比，其加工性能和介电性能受到主链上共轭苯并恶唑基团的严格限制，观察到聚（2-异丙烯基苯并恶唑）（P（2-IBO））在二甲基甲酰胺中的溶解性和介电常数（4.92）的改善，由于侧链上的偶极（苯并恶唑环）的高迁移率。此外，通过表面引发的N-（2-羟基苯基）甲基丙烯酰胺（o-HPMAA）（来自还原氧化石墨烯（RGO）的2-异丙烯基苯并恶唑的前体）的原子转移自由基聚合（ATRP）实现导电石墨烯纳米片的改善的分散。当官能化石墨烯的重量分数达到0.015时，官能化石墨烯和P（2-IBO）的纳米复合材料具有8.35的介电常数（在1 kHz下比纯P（2-IBO）的介电常数高约70%），这是迄今为止关于石墨烯/聚苯并恶唑系统的介电性质的报道中最低的。
The abilities to enhance the degree of orientational freedom of dipole in polymer dielectrics and strengthen the homogeneous dispersion of conductive fillers in matrix are of crucial importance for fabricating composite materials with high dielectric constant, low dielectric loss, low density, and good processability. Compared with conventional main-chain polybenzoxazoles, whose processability and dielectric performance are strictly limited by the conjugated benzoxazole groups on the backbone, improved solubility in dimethylformamide and dielectric constant (4.92) were observed for poly(2-isopropenylbenzoxazole) (P(2-IBO)), due to the high mobility of the dipole (benzoxazole ring) on the side chains. In addition, improved dispersion of conductive graphene nanosheets was achieved by a surface-initiated atom transfer radical polymerization (ATRP) of the N-(2-hydroxyphenyl)methacrylamide (o-HPMAA), the precursor of 2-isopropenylbenzoxazole from reduced graphene oxide (RGO). The nanocomposites of functionalized graphene and P(2-IBO) possess a dielectric constant of 8.35 (approximately 70% higher than that of pure P(2-IBO) at 1 kHz) when the weight fraction of functionalized graphene reaches 0.015, the lowest so far among the reports on dielectric property of the graphene/polybenzoxazole system.