The microstructure of stabilized fibers

Abstract The morphology and microstructure of a stabilized fiber, nonburning fiber, has been investigated under optical and electron microscopes, and a model for the structure of the stabilized fiber is presented. Skin‐core morphology was found in the cross section of the stabilized fiber. The proposed model is consistent with the lamellar‐plate‐like structure, measuring about 400–700 Å in thickness, 500–4000 Å in breadth and 0.1–0.5 μ m in length along the fiber axis, which is composed of microfibrils. The structure has some circumferential distribution in the outer zone, while the inner zone has a radical distribution. Evidence for the lamellar‐plate structure, including two chemical structures and having two different crystalline phases, which are the original AN units and the ladder polymer, were obtained from electron microscopy, wide‐angle X‐ray, and electron diffraction analyses.