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Polystyrene-attached graphene oxide with different graft densities via reversible addition-fragmentation chain transfer polymerization and grafting through approach
Applied Physics A ( IF 2.5 ) Pub Date : 2020-03-03 , DOI: 10.1007/s00339-020-3428-5
Hanieh Mardani , Hossein Roghani-Mamaqani , Khezrollah Khezri , Mehdi Salami-Kalajahi

Abstract Graphene oxide (GO) modified with double bond was utilized in grafting polystyrene chains to its surface through reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene. For this purpose, 3-(((2-aminoethyl)amino)dimethylsilyl)propyl methacrylate (OD) including double bond and amine groups was prepared and used for modification of GO in different grafting densities by a ring-opening nucleophilic reaction. Then, polystyrene-grafted GO was obtained by “grafting through” RAFT polymerization of styrene. Successful using of RAFT polymerization, efficiency of the grafting reaction, different characteristics of the graphene-attached and free polystyrene chains were investigated. Proton nuclear magnetic resonance spectroscopy confirmed successful synthesis of OD. Its grafting on GO was also confirmed by using X-ray photoelectron spectroscopy. The neat and modified GO layers were also investigated by Fourier transform infrared and Raman spectroscopies. Size exclusion chromatography was used to study molecular weight and polydispersity index of the attached polystyrene chains. Thermogravimetric analysis provides degradation temperature, char content, and grafting ratio of the modifier and polystyrene chains. Grafting ratio of OD was 10.3 and 4.4% for the modified GO layers with high and low grafting densities, respectively. Layers morphology was visually studied by scanning and transmission electron microscopies. Flat and smooth graphite platelets were changed to wrinkled layers after oxidation, and converted to opaque layers after grafting with polystyrene chains. High length of small molecule modifier in this study resulted in highly efficient grafting reaction. Graphic Abstract

中文翻译:

具有不同接枝密度的聚苯乙烯附着氧化石墨烯通过可逆加成断裂链转移聚合和接枝方法

摘要 利用双键修饰的氧化石墨烯 (GO) 通过苯乙烯的可逆加成断裂链转移 (RAFT) 聚合将聚苯乙烯链接枝到其表面。为此,制备了含有双键和胺基的甲基丙烯酸 3-(((2-氨基乙基)氨基)二甲基甲硅烷基)丙酯(OD),并通过开环亲核反应将其用于不同接枝密度的 GO 改性。然后,通过苯乙烯的 RAFT 聚合“接枝”获得聚苯乙烯接枝的 GO。研究了 RAFT 聚合的成功使用、接枝反应的效率、石墨烯连接和游离聚苯乙烯链的不同特性。质子核磁共振波谱证实成功合成了 OD。通过使用 X 射线光电子能谱也证实了它在 GO 上的接枝。还通过傅立叶变换红外光谱和拉曼光谱研究了整洁和改性的 GO 层。尺寸排阻色谱用于研究连接的聚苯乙烯链的分子量和多分散指数。热重分析提供了改性剂和聚苯乙烯链的降解温度、炭含量和接枝率。对于具有高和低接枝密度的改性 GO 层,OD 的接枝率分别为 10.3% 和 4.4%。通过扫描和透射电子显微镜目视研究层形态。平整光滑的石墨片氧化后变为褶皱层,接枝聚苯乙烯链后变为不透明层。本研究中的高长度小分子改性剂导致高效的接枝反应。图形摘要
更新日期:2020-03-03
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