The Polymer Society of Korea

Abstract

Understanding microstructure of carbon fiber is essential for establishing processing–structure–property linkages. Conventional methods (XRD, Raman, TEM) often yield partial views, making a unified microstructural sketch challenging. Small-angle X-ray scattering (SAXS) complements these by providing statistically representative descriptors of voids and crystallites. We present a SAXS-based workflow across four manufacturing stages: PAN stabilization, pitch carbonization, PAN carbonization, and PAN oxidation. SAXS resolves void origins during stabilization, captures domain-to-crystallite transformation in pitch fibers, reveals master-curves linking modulus to crystallite growth, and quantifies radial heterogeneity. Overall, SAXS integrates disparate measures into a coherent, process-linked sketch, enabling the rational optimization of carbon fibers and composites.