研究了聚丙烯腈(PAN)纤维在预氧化过程中致密结构的温度时间效应，通过体密度表征纤维的致密结构，并结合其他预氧参数如环化指数、环化度、氧含量及相对环化率的变化，全面分析研究了致密结构的形成演变特征及其梯度预氧化的温度效应和时间效应。结果表明：PAN预氧纤维环化程度的增高有利于致密结构形成，且碳纤维的力学性能与致密结构相关；PAN预氧纤维致密结构的温度效应体现在促进交联芳构化反应上，生成交联环化致密结构；时间效应表现为提高纤维的氧化能力，生成含氧环化梯形的致密结构。
Abstract
The effects of varying the treatment temperature and time on the dense structure formed during the stabilization of polyacrylonitrile (PAN) fibers have been studied by volume density measurements and the results analyzed using different stabilization indexes, such as cyclization index, oxygen content, cyclization degree, and relative cyclization rate. The evolution characteristics and the effects of temperature and time on the dense structure are described in detail. The results indicated that: formation of a dense structure is promoted by a degree of high preoxidation, and is strongly correlated with the mechanical properties of the resulting PAN based carbon fibers; higher stabilization temperatures caused more crosslinking reactions and aromatization, which produced a more cyclized network structure; longer stabilization times caused higher oxidative capacity, which produced cyclized structures with higher oxygen content.
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