Study on Hydrolysis Process of Polyacrylonitrile Fibers with Visualization Technique

Polyacrylonitrile (PAN) fibers were hydrolyzed in an alkaline condition, and the hydrolysis process was observed with a self-made visual device. Under the condition of mass ratio of PAN to NaOH to H₂O being 1:0.6:100, the sample was collected every 1 h and used for observation. It could be seen from the pictures obtained, the entire fiber surface was rough bark-like when they were hydrolyzed for 3 h. After 4 h, it showed a clear and grid structure, 5 h later a ring netting, and 6 h later the ring netting ruptured. Then they were decomposed completely into macro-molecules.