In situ synthesis of poly(ethylene terephthalate) (PET) in ethylene glycol containing terephthalic acid and functionalized multiwalled carbon nanotubes (MWNTs) as an approach to MWNT/PET nanocomposites
In situ synthesis of poly(ethylene terephthalate) (PET) in ethylene glycol containing terephthalic acid and functionalized multiwalled carbon nanotubes (MWNTs) as an approach to MWNT/PET nanocomposites
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DOI：
10.1021/cm051218t
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发表时间：
2005-10-04
影响因子：
8.6
通讯作者：
Baek, JB
中科院分区：
文献类型：
--
作者：
Lee, HJ;Oh, SJ;Baek, JB
多壁碳纳米管（MWNTs）（直径范围，10 - 20 nm）用4-甲氧基苯甲酸和4-乙氧基苯甲酸通过Friedel-Crafts反应在多磷酸中官能化，得到甲氧基苯甲酰基-和乙氧基苯甲酰基-官能化的MWNTs。将所得到的MWNT、甲氧基苯甲酰基官能化的（MeO-MWNT）和乙氧基苯甲酰基官能化的（EtO-MWNT）纳米管分散在乙二醇（EG）中。由于结构相似性，EtO-MWNT（0.4wt%）和EG的混合物是均匀分散体，而MeO-MWNT和原始MWNT在相同负载下相当不均匀地分散在EG中。在原始MWNT、MeO-MWNT或EtO-MWNT存在下进行EG和对苯二甲酸的原位缩聚以生成相应的MWNT/PET、MeO-MWNT/PET和EtO-MWNT/PET纳米复合材料。在所有情况下都获得了特性粘度范围为0.6 - 0.7 dL/g（邻氯苯酚，30 +/-0.1 ℃）的高分子量聚（对苯二甲酸乙二醇酯）（PET）。在比较这些纳米复合材料在相同放大率下拍摄的扫描电子显微镜（SEM）图像时，很明显，MWNT/PET系统具有差的MWNT分散性，而MeO-MWNT/PET系统具有更好的分散性。然而，EtO-MWNT在PET基体中是最均匀分散的，并且EtO-MWNT与PET基体之间的界面边界几乎不可辨别。
Multiwalled carbon nanotubes (MWNTs) (diameter range, 10-20 nm) were functionalized with 4-methoxybenzoic acid and 4-ethoxybenzoic acid via a Friedel-Crafts reaction in polyphosphoric acid to afford methoxybenzoyl- and ethoxybenzoyl-functionalized MWNTs. As-received MWNT, methoxybenzoyl-functionalized (MeO-MWNT), and ethoxybenzoyl-functionalized (EtO-MWNT) nanotubes were dispersed in ethylene glycol (EG). Because of the structural similarity, the mixture of EtO-MWNT (0.4 wt %) and EG was a homogeneous dispersion, whereas MeO-MWNT and pristine MWNT were dispersed in EG rather heterogeneously at the same loading. In situ polycondensation of EG and terephthalic acid in the presence of pristine MWNT, MeO-MWNT, or EtO-MWNT was carried out to generate the corresponding MWNT/PET, MeO-MWNT/PET, and EtO-MWNT/PET nanocomposites. High molecular weight poly(ethylene terephthalates) (PETs), with intrinsic viscosity range 0.6-0.7 dL/g (o-chlorophenol at 30 +/- 0.1 degrees C), were obtained in all cases. In comparing the images from scanning electron microscopy (SEM) taken at the same magnification for these nanocomposites, it is clear that the MWNT/PET system has poor MWNT dispersion and the MeO-MWNT/PET system has a better dispersion. However, EtO-MWNT in PET matrix is most homogeneously dispersed, and the interfacial boundary between EtO-MWNT and PET matrix is practically nondiscernible.