Radial structure and property relationship in the thermal stabilization of PAN precursor fibres
Radial structure and property relationship in the thermal stabilization of PAN precursor fibres
复制标题
DOI：
10.1016/j.polymertesting.2017.02.006
复制
发表时间：
2017-05-01
期刊：
影响因子：
5.1
通讯作者：
Fox, Bronwyn L.
中科院分区：
文献类型：
--
作者：
Nunna, Srinivas;Creighton, Claudia;Fox, Bronwyn L.
在这里，我们报告的作用，氧的径向不均匀性的演变中的纤维结构和性能的PAN纤维稳定在空气和真空中，在不同的温度。纳米压痕模量映射显示在空气中处理的纤维中的非均匀模量分布，而在真空中处理的纤维中没有观察到模量的变化。拉曼光谱和元素分析表明，温度依赖性的氧从皮肤到芯的纤维的扩散有助于在皮肤中的sp（2）-杂化碳相比，在空气处理的样品的芯更高的程度的演变。相反，在真空处理的纤维中没有观察到径向结构变化。在空气处理的纤维的皮肤中的较高模量是由于形成紧凑的结构，这是与增强的分子间相互作用促进的聚合物主链内的C=C键的形成，促进氧化脱氢反应。支持这些观察结果，通过SEM检查的断裂形态显示在皮肤中的脆性断裂和在核心中的韧性断裂。(C)2017爱思唯尔有限公司版权所有
Here we report on the role of oxygen in the evolution of radial heterogeneity in the fibre structure and properties of PAN fibres stabilized in air and vacuum at different temperatures. Modulus mapping by Nano-indentation showed heterogeneous modulus distribution in the fibres treated in air, while no variation in modulus was observed in fibres processed in vacuum. Raman spectroscopy and elemental analysis revealed that the temperature dependent oxygen diffusion from skin to core of the fibres assisted in the evolution of higher extent of sp(2)-hybridized carbons in the skin compared to core of the air treated samples. Conversely, no radial structure variations were observed in the vacuum treated fibres. Higher modulus in the skin of air-treated fibres was due to the formation of compact structures which was associated with the enhanced intermolecular interactions facilitated by the formation of C=C bonds within the polymer backbone, promoted by oxidative-dehydrogenation reaction. Supporting these observations, the fracture morphology examined by SEM showed a brittle fracture in the skin and ductile fracture in the core. (C) 2017 Elsevier Ltd. All rights reserved.