writer：Defeng Wu, Tiejun Shi, Tao Yang, Yurong Sun, Linfeng Zhai, Weidong Zhou, Ming Zhang
keywords：poly(trimethylene terephthalate); carbon nanotubes; composites; rheology; electrospinning.
source：期刊
specific source：European Polymer Journal
Issue time：2011年

European Polymer Journal, 2011, 47(3), 284-293.

ABSTRACT:

Poly(trimethylene terephthalate) (PTT) nanocomposites containing various carbon nanotubes (CNTs) were prepared by melt compounding for electrospinning. The dispersion state of the CNTs in the composites was then examined utilizing rheology tools. The results show that the carboxylic CNTs present better dispersion in the matrix than the hydroxy CNTs because the former has stronger affinity to the PTT. Besides surface functionalization, the aspect ratio of CNTs is also vital to their final dispersion. The CNTs with lower aspect ratio are dispersed as individuals or small bundles while those with higher aspect ratio are dispersed mainly as flocs with large hydrodynamic radius, showing higher effective volume fraction. The presence of CNTs has large influence on the morphologies of electrospun fiber and on the appearances of CNTs in the fibers. In the presence of CNTs with lower aspect ratio, continuous composite fibers are obtained. But the structures of those continuous fibers highly depend on the surface group of CNTs. The carboxylic CNTs are well embedded by the PTT and oriented along the fiber axis during electrospinning, leading to bead-free and uniform fiber morphology; while the hydroxy CNTs show tortuous conformations with less orientation in the fibers, and as a result, the obtained fibers show beaded and misshaped morphologies. In the case of higher aspect ratio, however, the CNTs prefer to exist as entanglements or knots in the streamlines, and thereby only beaded or even uncontinuous fibers are obtained. Therefore, the formation of the PTT/CNT composite fiber depends on the surface groups and structure parameters of CNTs strongly.

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