Study on the chemical structure and skin-core structure of polyacrylonitrile-based fibers during stabilization

The chemical structure and the skin-core structure of the fiber during stabilization were investigated by FT-IR, elemental analysis, optical microscopy (OM), SEM, TEM and Energy Dispersive X-ray Detector (EDX). The experimental results show that the oxygen content in the skin of the stabilized fiber is more than that in the core, resulting in the inhomogeneity structure of the stabilized fiber. The cross-section of the stabilized fiber presents concentric multi-layer ring-like morphology, the outmost thin and dense skin layer, followed by the cortex layer, the endothelium layer and the core layer. The stabilized fiber is consisted of sheet-like structure in the microstructure images, but there is some difference between the skin and the core. Not only the orientation of the skin is better than the core, but also the skin structure is more compact and homogenous than the core.