A grafting from approach to graft polystyrene chains at the surface of graphene nanolayers by RAFT polymerization: Various graft densities from hydroxyl groups
A grafting from approach to graft polystyrene chains at the surface of graphene nanolayers by RAFT polymerization: Various graft densities from hydroxyl groups
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DOI：
10.1016/j.apsusc.2015.11.041
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发表时间：
2016
影响因子：
6.7
通讯作者：
H. Roghani‐Mamaqani;K. Khezri
中科院分区：
文献类型：
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作者：
H. Roghani‐Mamaqani;K. Khezri
以不同接枝密度在氧化石墨烯表面接枝（3-氨基丙基）三乙氧基硅烷，分别得到了GOHAL和GOHAH。随后，2-（十二烷基硫代碳硫代基硫）-2-甲基丙酸（RA）通过酰胺化反应附着在GOHAL和GOHAH表面，分别得到GOHRL和GOHRH。然后用GOHRL和GOHRH进行RAFT聚合接枝。傅里叶变换红外光谱、x射线光电子能谱和拉曼光谱证实了APTES和RA的接枝。用x射线衍射评价了氧化和功能化过程对石墨烯中间层的膨胀作用。用气相色谱法计算了苯乙烯的转化值。采用粒径不相容色谱法研究了聚苯乙烯（PS）链的分子量和PDI值。用热重分析法考察了改性剂和PS链的降解温度、炭含量和接枝含量。600℃时GOHRH和GOHRL的焦炭含量分别达到55.3和45.2%，表明改性剂（APTES和RA）的重量比分别为15.3%和5.2%。扫描电镜和透射电镜观察发现，表面平整光滑的石墨层经氧化后起皱，接枝PS后变为不透明层。
(3-Aminopropyl) triethoxysilane was grafted at the surface of GO in low and high different graft densities to yield GOHAL and GOHAH, respectively. Subsequently, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (RA) was attached at the surface of GOHAL and GOHAH by an amidation reaction to yield GOHRL and GOHRH, respectively. Then, GOHRL and GOHRH were used in grafting from RAFT polymerization of styrene. Grafting of APTES and RA was approved by Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, and Raman spectroscopy. Expansion of graphene interlayer by oxidation and functionalization processes was evaluated by X-ray diffraction. Conversion values of styrene were calculated using gas chromatography. Molecular weight and PDI values of attached polystyrene (PS) chains were studied by size exclusion chromatography. Thermogravimetric analysis was also used to investigate the degradation temperatures, char contents, and graft contents of modifiers and PS chains. GOHRH and GOHRL reach to char content of 55.3 and 45.2% at 600 °C, which shows that weight ratio of modifier (APTES and RA moieties) is 15.3 and 5.2%, respectively. Scanning and transmission electron microscopies show that graphite layers with flat and smooth surface wrinkled after oxidation and turned to opaque layers by grafting PS.