Chen Liang, Shen Zhigang, Liu Jie, Liang Jieying, Wang Xiaoxu
Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology Chao-Yang District Beijing 100029 China
SINOPEC Shanghai Research Institute of Petrochemical Technology 1658 Pudong North Road, Pudong District Shanghai 201208 China.
RSC Adv. 2020 Feb 11;10(11):6356-6361. doi: 10.1039/c9ra08881d. eCollection 2020 Feb 7.
In this study, the mechanism of stabilizing polyacrylonitrile (PAN) fibers in a short period of time is investigated through probing the effects of oxygen on the structural evolution of PAN under different temperature regimes. It has been found that oxygen has a significant influence on both the chemical and physical structural evolution of PAN fibers, even in a short period of stabilization time, and the influences are dissimilar at different stabilization temperatures. At lower temperatures (below 140 °C), there is no noticeable change in the chemical and physical structures of the PAN fibers. In the mid-temperature range (140-200 °C), oxygen can slightly induce the cross-linking of PAN chains and result in a higher rate of decreasing crystallinity. When the main chemical reactions are initiated at higher temperatures (200-260 °C), oxygen is directly involved in the oxidation reaction of the PAN chains and facilitates cyclization and dehydrogenation. These reactions initiate in the amorphous regions of PAN fibers, and extend to the crystalline regions at elevated temperatures.
在本研究中，通过探究氧气在不同温度条件下对聚丙烯腈（PAN）结构演变的影响，研究了在短时间内稳定PAN纤维的机理。研究发现，即使在短时间的稳定化过程中，氧气对PAN纤维的化学和物理结构演变也有显著影响，且在不同的稳定化温度下影响不同。在较低温度（低于140℃）时，PAN纤维的化学和物理结构没有明显变化。在中温范围（140 - 200℃），氧气可轻微诱导PAN链的交联，并导致结晶度降低速率更高。当在较高温度（200 - 260℃）引发主要化学反应时，氧气直接参与PAN链的氧化反应，并促进环化和脱氢反应。这些反应在PAN纤维的非晶区开始，并在升高的温度下扩展到结晶区。
