Abstract
Polyacrylonitryle (PAN) fibers are used on a large scale in textile industry but, some sorts of PAN fibers are valuable precursors for specific carbon fiber (CF) due to their best fitness to the purpose e.g. for high strength CF or for active CF. The application of PAN as precursors of CF is based on its specific structure and texture. Thus, the properties of PAN base CF strongly depend on PAN structure, texture and fiber morphology. In this respect, the paper addresses the modeling of PAN fiber structure and texture and, subsequently, estimation of structure and texture parameters based mainly on Wide Angle X-ray Diffraction (WAXD) technique but, on SEM and other data. The PAN fiber structure and texture parameters were calculated on the basis of classical X-ray diffraction theory applied to paracrystals. The preferred orientation parameters were calculated on a wide accepted model. The main structural parameter of PAN paracrystal d200, d201, and L200 and preferred orientation/texture parameters Z, [cos2 u], P (cos2 u) of the PAN fibers were determinated. Based on WAXD data it was calculated the PAN fiber crystallinity. As it results from the paper the WAXD technique seems to be the best from the efficiency-cost point of view for PAN structure and preferred orientation characterization. Keywords: WAXD, SEM, structure, preffered orientation, polyacrylonitryle fibers