To reveal the enhancement effect of graphene oxide (GO) in polymer nanofiber yarns, polyacrylonitrile (PAN)/GO nanofibers with different GO content (0.1‐0.5 wt%) were electrospun. The alignment of PAN chains and GO in nanofibers was enhanced by hot stretching of the yarn in dry conditions. The microstructure of the composite nanofiber yarns was investigated through X‐ray diffraction, polarized Fourier transform infrared spectroscopy and transmission electron microscopy. The results demonstrated that the hot stretching above T_g of PAN precursor lead to the increased orientation‐induced crystallization and alignment of PAN chain and GO. The yarn with 0.1 wt% GO and stretched by 4 times its length obtained the highest strength and modules (310.88 ± 24.68 MPa and 7.24 ± 0.55 GPa), which were 600% and 500% higher than those of the as‐electrospun pure PAN yarn. The most promising tensile properties found in hot stretched yarns with low GO content was because the strong interaction occurred between PAN molecules and oxygen‐containing functional groups. Indirect evidence of GO aggregation was also presented, which adversely affected the mechanical properties at higher GO content. Composite nanofiber yarns were sewable and weavable, and could be used as a new generation of composite reinforcement after pyrolysis.

中文翻译：

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热拉伸氧化石墨烯增强聚丙烯腈纳米纤维纱的微观结构演变及力学研究

为了揭示氧化石墨烯（GO）在聚合物纳米纤维纱线中的增强作用，对具有不同GO含量（0.1-0.5 wt％）的聚丙烯腈（PAN）/ GO纳米纤维进行了电纺。通过在干燥条件下热拉伸纱线，可以增强PAN链和GO在纳米纤维中的排列。通过X射线衍射，偏振傅立叶变换红外光谱和透射电子显微镜研究了复合纳米纤维纱的微观结构。结果表明，T _g以上的热拉伸PAN前体的存在导致取向诱导的PAN和GO的结晶和排列增加。GO含量为0.1 wt％并拉伸其长度4倍的纱线获得了最高的强度和模量（310.88±24.68 MPa和7.24±0.55 GPa），分别比电纺纯PAN纱线高600％和500％ 。在GO含量低的热拉伸纱中发现的最有希望的拉伸性能是因为PAN分子与含氧官能团之间发生了强烈的相互作用。还显示了GO聚集的间接证据，这对较高GO含量的机械性能产生不利影响。复合纳米纤维纱线是可缝制和可编织的，可以用作热解后的新一代复合增强材料。