The micro-void structure transformation and properties assessment of polyacrylonitrile fibers irradiated by electron-beam as carbon fiber precursor

• Published in: Polymer testing 2021-07, Vol.99, p.107218, Article 107218
• Main Authors: Zhang, Hao, Liu, Weihua, Ding, Yi, Tian, Feng, Tang, Zhongfeng
• Format: Article
• Language: English
• Subjects: Cross-linking; Degradation; Fibers; Polyacrylonitrile; Radiation; Small-angle X-ray scattering
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2021.107218

PAN fibers were irradiated by electron-beam at room temperature in air. The micro-void structure transformation and properties of irradiated PAN fibers were characterized using gel permeation chromatograph, small angle X-ray scattering, differential scanning calorimetry, thermogravimetric analysis and tensile strength. The cross-linking occurred dominantly, and the stable polymer network formed. The gel fraction got saturated at 200 kGy and did not further increase due to the oxidation degradation. The lateral size of micro-voids and the dose were negatively correlated while the length and misorientation of micro-voids expanded with dose increased (61.73 nm–201.06 nm, 7.79°–11.86°). The intense heat release of cyclization reaction was efficiently relieved by irradiation. Meanwhile, carbon yield at 800 °C also increased from 43% to 55% after irradiation at 200 kGy, which increased by 25% compared with original PAN fibers. This study can prefer irradiation conditions to improve PAN based carbon fiber property. •SAXS was firstly used to study the micro-voids structure of irradiated PAN fibers.•Transformation of micro-voids led to a decline in mechanical properties.•Crosslinking caused a reduction in the lateral size of micro-voids for PAN fibers.•Carbon yield at 800 °C increased to 54.9% after irradiation.