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前人曾报导聚丙烯腈(PAN)纤维在加压、或在酸碱催化下的水解研究。本文叙述了PAN废丝在ZnCl_2催化下的水解过程,和各种条件对PAN水解产物的粘度和组成的影响。扫描电镜实验发现,水解过程中PAN纤维发生溶胀现象。水解过程经历了纤维颜色由浅变深、溶胀出现弹性增大,进而水解成水溶性产物。我们采用了红外光谱法跟踪PAN纤维水解过程中官能团的变化,并测定其水解度。在此基础上提出了ZnCl_2催化系统的PAN水解机理。借助差热—重量分析(DTA—TG)研究了不同水解条件得到的产物的热稳定性。DTA—TG实验证明,水解产物热稳定性不受水解反应条件的影响,热裂至600℃时,残留物仍占16％,这说明其裂解过程不完全相同于聚丙烯酰胺(PAM)。
Previous reports on polyacrylonitrile (PAN) fibers under pressure, or acid-base catalyzed hydrolysis studies. This paper describes the hydrolysis of PAN waste wire catalyzed by ZnCl 2 and the influence of various conditions on the viscosity and composition of the PAN hydrolyzate. Scanning electron microscopy experiments found that during the hydrolysis of PAN fibers swell phenomenon. The hydrolysis process has gone through the fiber from light to dark, swelling appears elastic increases, and then hydrolyzed into water-soluble products. We used infrared spectroscopy to trace the change of functional groups during the hydrolysis of PAN fibers and determine their degree of hydrolysis. On this basis, the mechanism of PAN hydrolysis in ZnCl 2 catalytic system was proposed. The thermal stability of the products obtained under different hydrolysis conditions was investigated by means of DTA-TG. The results of DTA-TG show that the thermostability of the hydrolyzate is not affected by the hydrolysis reaction conditions. When the temperature is 600 ℃, the residue still accounts for 16%, indicating that the pyrolysis process is not completely the same as the polyacrylamide (PAM).