Laser induced graphitization of PAN-based carbon fibers

Yang Sha; Weimin Yang; Sanyang Li; Liangbo Yao; Haoyi Li; Lisheng Cheng; Hua Yan; Weiyu Cao; Jing Tan

doi:10.1039/c8ra00497h

Laser induced graphitization of PAN-based carbon fibers

RSC Adv. 2018 Mar 23;8(21):11543-11550. doi: 10.1039/c8ra00497h. eCollection 2018 Mar 21.

Authors

Yang Sha^{1

2}, Weimin Yang^{1

3}, Sanyang Li³, Liangbo Yao³, Haoyi Li³, Lisheng Cheng³, Hua Yan^{1

3}, Weiyu Cao^{1

2}, Jing Tan^{1

3}

Affiliations

¹ State Key Laboratory of Organic-Inorganic Composites, College of Material Science and Engineering, Beijing University of Chemical Technology Beijing 100029 China caowy@mail.buct.edu.cn.
² The Key Laboratory of Education Ministry on Carbon Fibre and Functional Polymer, Beijing University of Chemical Technology Beijing 100029 China.
³ College of Mechanical and Electronic Engineering, Beijing University of Chemical Technology Beijing 100029 China tanj@mail.buct.edu.cn.

Abstract

Laser induced graphitization of polyacrylonitrile-based carbon fibers (CFs) was carried out in a self-designed furnace with a CO₂ laser source. The microstructures combined with mechanical properties of the irradiated CFs were measured by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and single filament tensile test, respectively. The results exhibited that the hierarchical structures of CFs showed different responses to the CO₂ laser. After laser graphitization, the surface and cross-section structure were characterized by Raman spectroscopy. As the power density increased, a profound increase of graphitization degree happened and obvious skin-core structures were observed. Furthermore, the results of XPS measurements indicated that the irradiated CFs showed more conjugated structures. For crystallite structure, the interlayer spacing of the (002) lattice decreased and the thickness of crystallite increased after graphitization. The size of the (002) lattice parallel to the fiber axis changed slightly. The surface morphology was also investigated by SEM, sheet structures and particles could be observed on the surface of CFs. This was attributed to fast energy addition of laser and the characteristics of the material. Further HRTEM investigation revealed that the sheet structure is multilayered graphene. The Young's modulus of irradiated fibers showed obvious improvements compared to that of as-received ones.