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Carbon nanotube-reinforced carbon nano-composite fibrils by electro-spinning.

机译:碳纳米管增强的碳纳米复合原纤维的电纺丝。

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Fibers of Polyacrylonitrile (PAN) are the precursor of 90% of produced carbon fibers. It is generally thought that the better the degree of molecular orientation in the original PAN fiber, the better the mechanical properties, in particular the modulus of the resultant fibers.; Electro-spinning is a unique process in that it is able to produce polymer fibers having diameters ranging over several orders of magnitude, from the micrometer range typical of conventional fibers down to the nanometer range.; Until now and based on the literature review the shape and pattern of produced fibers in all electro-spun polymer solutions have taken an in-plan random pattern and affected by the shape of the collector, which gives a limitation of using these ultra fine produced fibers in textile applications.; A notable phenomenon has been recognized under certain spinning conditions for PAN solution, which enable the production of continuous yarn containing partially oriented nano-fibers. This phenomenon opened the door to achieve many objectives such as the production of carbon-carbon nano composites by dispersing (CNT) of superior physical properties inside the PAN polymer solution and producing continues carbon nanotube reinforced PAN based carbon nano composite fibrils.; The present study is an attempt to optimize the electro-spinning process for nano-scale fibers, understand the electro-mechanics of electro-spun continuous nano-fiber yarns, stabilize, carbonize and graphitize of nano fiber yarns with and without CNT and finally study the physical, chemical and mechanical properties of the produced carbon nanotube reinforced PAN based carbon nano composite fibrils before and after heat treatments.; The HREM results showed a good alignment for the CNT inside the PAN based carbon nano fiber composites as well as an increase in the crystallite size up to 5nm, which calculated based on Raman spectroscopy measurements.; The AFM showed a two-folds increase in the composite modulus more than the calculated modulus from the rule of mixtures in stabilized case while it reduced to 1.3 folds after graphitization. However, that increase defined as “nano effect” has been explained as a result of the interaction between the nano reinforcements (CNT) and PAN polymer molecular chains.
机译:聚丙烯腈(PAN)纤维是90%生产的碳纤维的前体。通常认为,原始PAN纤维中的分子取向度越好,机械性能,特别是所得纤维的模量越好。电纺丝是一种独特的工艺,因为它能够生产出直径在几个数量级范围内的聚合物纤维,从常规纤维的典型微米范围到纳米范围。到目前为止,根据文献回顾,在所有电纺聚合物溶液中生产的纤维的形状和图案均呈平面内随机图案,并受集电器形状的影响,这限制了使用这些超细生产的纤维的局限性在纺织应用中。在某些纺丝条件下,对于PAN溶液已经发现了一种值得注意的现象,该现象使得能够生产出包含部分取向的纳米纤维的连续纱线。这种现象为实现许多目标打开了大门,例如通过将PAN溶液中的优异物理性能分散(CNT)来生产碳-碳纳米复合材料,并继续生产碳纳米管增强的PAN基碳纳米复合纤维。本研究旨在优化纳米级纤维的电纺工艺,了解电纺连续纳米纤维纱的电学机理,对具有和不具有CNT的纳米纤维纱进行稳定,碳化和石墨化处理,最后进行研究在热处理之前和之后,所生产的碳纳米管增强的PAN基碳纳米复合原纤维的物理,化学和机械性能。 HREM结果表明,PAN基碳纳米纤维复合材料内部的CNT具有良好的取向,并且晶粒尺寸增加了5nm,这是根据拉曼光谱测量得出的。在稳定情况下,AFM的复合模量比混合物的模量计算出的模量增加了两倍,而在石墨化后,其降低到了1.3倍。但是,由于纳米增强剂(CNT)和PAN聚合物分子链之间的相互作用,已经解释了这种被定义为“纳米效应”的增加。

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