采用傅里叶红外和动态热机械分析仪对中间相沥青纤维预氧化过程进行研究.结果表明,纤维中的应力在175 ℃前迅速降低;在氧化过程中,脱氢反应显著,同时羟基减少;到250 ℃以上醚键增加,大量的交联反应发生,应力增大,在恒定应力下纤维伸长速率减缓;270 ℃以上时纤维稳定化程度较高,产生收缩;整个氧化过程中含氧官能团的增加并不显著.结合纤维在垂直和水平两种状态下的受力分析认为,连续预氧化时,沥青纤维自身重力不容忽略,沥青预氧化炉宜采用立式设计.
The stress in and elongation of mesophase pitch fibers during oxidative stabilization were investigated by a dynamic thermo-mechanical analyzer under a fixed elongation and strainload, respectively.Their functional groups at different temperatures were characterized by Fourier transformed infrared spectroscopy.Results indicated that when the temperature was below 175 ℃, a distinct decrease in the stress in the fibers and the number of hydroxyl groups was found, accompanied by dehydrogenation reactions.When the temperature was increased above 250 ℃, the number of ether bonds and the stress increased, and elongation decreased due to cross-linking reactions.When the temperature was increased further, above 270 ℃, the fibers began to shrink because of the increase in the extent of stabilization.It was found, based on dynamic thermo-mechanical data, that the effect of gravity on the fiber cannot be neglected in designing a stabilization furnace and a vertical furnace is superior to a horizontal one.
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