Effect of temperature and holding time on preoxidation for aligned electrospun polyacrylonitrile nanofibers



In this article, aligned electrospun polyacrylonitrile nanofiber bundles were prepared as the precursor fibers to prepare preoxidized nanofibers through washing, drying densification, damp-heat drafting, and preoxidation process. Effects of preoxidation temperature and holding time on appearance and microstructure of the preoxidized fibers were studied. Fiber density is increased from 1.159 to 1.193 g cm−3 after drying densification. Crystallinity is increased from 22.66 to 45.90% after fourfold drafting. The aligned preoxidized nanofibers were prepared at the optimum preoxidation temperature of 283°C, heating speed of 1°C min−1, and holding time of 1 h show a sufficient reaction degree of cyclization and crosslinking. Moreover, there is no occurrence of adhesion between fibers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1158-1163, 2013