Templating effect of 2,9-dimethylquinacridone nanocrystals on structural evolution and mechanical properties of polyacrylonitrile-based carbon fibers

Abstract

This study explores the templating role of organic nanocrystals, specifically 2,9-dimethylquinacridone (PR), in enhancing the mechanical performance of polyacrylonitrile (PAN)-derived carbon fibers. By incorporating PR—structurally analogous to the acridone units formed during PAN stabilization—into the PAN matrix, we investigate how these nanofillers direct the crystalline evolution and reinforce the resulting carbon fibers. PAN/PR nanocomposite fibers were prepared by dry-jet wet spinning, followed by stabilization and arbonization. Microstructural analysis reveals that well-dispersed PR nanocrystals serve as efficient nucleation sites, catalyzing the development of ordered carbon crystalline domains during heat treatment. As a result, carbon fibers containing 1 wt% PR displayed a pronounced increase in tensile strength and modulus (16 % and 13 % higher, respectively, than control samples), attributed to optimal PAN-PR interaction and effective templating effects. These findings demonstrate that the templating behavior of organic crystalline nanofillers can be harnessed to simultaneously promote carbon crystal growth and reinforce mechanical properties in PAN-based carbon fibers. Our results highlight an efficient approach to nanofiller incorporation, establishing 2,9-dimethylquinacridone as a promising, non-polymeric reinforcement for next-generation high-performance carbon fibers.