氟化石墨烯结构表征及接枝增强芳纶Ⅲ薄膜的力学性能

首先对自制的氟化石墨烯(FG)进行结构与性能表征。然后采用拥有优异耐热性和分散性的FG对芳纶Ⅲ(PA)薄膜进行共混改性,提高其力学性能。PA分子链的咪唑环上的氮原子因弱碱性而具备亲核反应能力,有望取代氟化石墨烯的氟原子形成C-N键,进而有效增强聚合物基体。然而,研究发现,PA胶液中的HCl会与咪唑环络合,降低咪唑环的反应活性。吡啶的加入中和了HCl的同时也能够催化反应,促进C-N的生成。红外光谱结果表明,加入吡啶的FG-PA复合体系能够形成基体与填料间的C-N共价键接。同时,加入吡啶所制得的FG-PA共混薄膜相比未加入吡啶的拉伸强度增加了25.6%。

Characterization of Fluorinated Graphene and Its Reinforced Aromatic Polyamide Film

The structure and performance of fluorinated graphnene were characterized.The aromatic polyamide (PA) film containing benzimidazole moieties was further enhanced by the fluorinated graphene with high fluorine/carbon ratio and corresponding excellent thermal stability and dispersibility.The benzimidazole shows weak basicity and thus nucleophilic reactivity,which is supposed to react with the C-F bonds in fluorinated graphene sheets and form the C-N bonds covalently linking the rmacromolecules and graphene sheets.However,HCl in the PA solution would hinder the fluorine atoms being substituted by the benzimidazole because it complexed with the imidazole ring and transformed the basicity of macromolecules to acidity.Here,pyridine was added to neutralize HCl.Combining the catalysis of pyridine,PA molecules were in-situ eovalently grafted on fluorinated graphene sheets,which was confirmed by Fourier transform infrared spectroscopy.And the tensile strength of composite film improves 25.6％compared with none-pyridine one.