New aspects in the oxidative stabilization of PAN-based carbon fibers .2.
New aspects in the oxidative stabilization of PAN-based carbon fibers .2.
复制标题
DOI：
10.1016/s0008-6223(97)00025-0
复制
发表时间：
1997-01-01
期刊：
影响因子：
10.9
通讯作者：
Harrison, IR
中科院分区：
文献类型：
--
作者：
Gupta, A;Harrison, IR
最近提出了一种详细描述氧化稳定化过程中共聚物PAN（聚丙烯腈）纤维中形态发展的模型（Gupta和Harrison，Carbon，1996，34，1427）。该模型的一些主要特征是：（a）两步氧化稳定化过程，其中反应在无定形相中开始，并在高温下进展到结晶相;（B）分子内环化反应主导稳定化过程的早期部分，分子间交联发生在较高温度和氧的存在下;（c）沿纤维轴的宏观收缩沿着主要是熵驱动的过程，其中“化学"效应用于改变熵响应;和（d）为了实现完全的氧化稳定，类似于380 ℃的最终热处理温度（HTT）似乎是必要的。在目前的工作中，拉伸试验和X射线实验的结果有助于验证所提出的模型。等温稳定的研究表明，与快速和更有效的恒温斜坡过程相比，没有任何好处。此外，为了在氩气中稳定，脱氢是一个缓慢的过程，这使我们相信，前体纤维的拉伸可以在很宽的温度范围内进行。(C)1997年爱思唯尔科学有限公司
A model detailing the development of morphology in copolymer PAN (polyacrylonitrile) fibers during oxidative stabilization was recently proposed (Gupta and-Harrison, Carbon, 1996, 34, 1427). Some of the main features of this model are: (a) a two-step oxidative stabilization process wherein reactions initiate in the amorphous phase, and progress to the crystalline phase at high temperatures; (b) intramolecular cyclization reactions dominating the early part of the stabilization process, intermolecular cross-linking occurring at higher temperatures and in the presence of oxygen; (c) macroscopic shrinkage along the fiber axis primarily being an entropy-driven process, with ''chemical'' effects serving to modify the entropic response; and (d) a final heat treatment temperature (HTT) of similar to 380 degrees C seemed to be necessary in order to effect complete oxidative stabilization. In the current work, results from tensile testing and X-ray experiments help in validating the proposed model. Studies on isothermal stabilization indicate no benefits when compared to a rapid and more effective constant temperature ramp process. Additionally, for stabilization in argon, dehydrogenation is a slow process, leading us to believe that stretching of precursor fiber could be carried out over a wide temperature range. (C) 1997 Elsevier Science Ltd.