Effects of γ-Ray Irradiation on the Radial Structure Heterogeneity in Polyacrylonitrile Fibers during Thermal Stabilization

• Main Authors: Wei Dang, Jie Liu, Xiangyu Huang, Jieying Liang, Chunhua Wang, Peng Miao, Yongzhen An, Xiaoxu Wang
• Format: Article
• Language: English
• Published: MDPI AG 2018-08-01
• Series: Polymers
• Subjects: polyacrylonitrile fibers; radial structure heterogeneity; γ-ray irradiation; thermal stabilization
• Online Access: http://www.mdpi.com/2073-4360/10/9/943

The radial structural heterogeneity of thermally-stabilized polyacrylonitrile (PAN) fiber is considered to be a limiting factor affecting the mechanical properties of the resulting carbon fibers. In this study, we demonstrate that a low-dose (60 kGy) γ-ray irradiation pretreatment can effectively mitigate the radial structural heterogeneity of PAN fibers after thermal stabilization. The characterization results indicate that low-dose γ-ray irradiation only affects the physical structure of PAN through decreasing its crystalline size and crystallinity, rather than inducing chemical cross-linking and/or intramolecular cyclization. It is proposed that an increased amorphous region in PAN fibers prompted by low-dose γ-ray irradiation can facilitate oxygen diffusion from skin to core during stabilization, which results in the increased structural homogeneity of stabilized PAN fibers.