The Impact of Shear and Elongational Forces on Structural Formation of Polyacrylonitrile/Carbon Nanotubes Composite Fibers during Wet Spinning Process

Hamideh Mirbaha; Parviz Nourpanah; Paolo Scardi; Mirco D'incau; Gabriele Greco; Luca Valentini; Silvia Bittolo Bon; Shahram Arbab; Nicola Pugno

doi:10.3390/ma12172797

The Impact of Shear and Elongational Forces on Structural Formation of Polyacrylonitrile/Carbon Nanotubes Composite Fibers during Wet Spinning Process

Materials (Basel). 2019 Aug 30;12(17):2797. doi: 10.3390/ma12172797.

Authors

Hamideh Mirbaha^{1

2}, Parviz Nourpanah³, Paolo Scardi⁴, Mirco D'incau⁴, Gabriele Greco², Luca Valentini⁵, Silvia Bittolo Bon⁵, Shahram Arbab⁶, Nicola Pugno^{7

8

9}

Affiliations

¹ Department of Textile Engineering, Amirkabir University of Technology, 15875-4413 Tehran, Iran.
² Laboratory of Bio-inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, 38123 Trento, Italy.
³ Department of Textile Engineering, Amirkabir University of Technology, 15875-4413 Tehran, Iran. pnx@aut.ac.ir.
⁴ Department of Civil, Environmental and Mechanical Engineering, University of Trento, 38123 Trento, Italy.
⁵ Civil and Environmental Engineering Department, University of Perugia and INSTM Research Unit, 05100 Terni, Italy.
⁶ Advanced Textile Materials and Technology Research Institute, Department of Textile Engineering, Amirkabir University of Technology, 15875-4413 Tehran, Iran.
⁷ Laboratory of Bio-inspired & Graphene Nanomechanics, Department of Civil, Environmental and Mechanical Engineering, University of Trento, 38123 Trento, Italy. nicola.pugno@unitn.it.
⁸ School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK. nicola.pugno@unitn.it.
⁹ Ket-Lab, Edoardo Amaldi Foundation, 00133 Rome, Italy. nicola.pugno@unitn.it.

Abstract

Wet spinning of polyacrylonitrile/carbon nanotubes (PAN/CNT) composite fibers was studied and the effect of spinning conditions on structure and properties of as-spun fibers influenced by the presence of CNTs investigated. Unlike PAN fibers, shear force had a larger effect on crystalline structure and physical and mechanical properties of PAN/CNT composite fibers compared to the elongational force inside a coagulation bath. Under shear force CNTs induced nucleation of new crystals, whereas under elongational force nucleation of new crystals were hindered but the already formed crystals grew bigger. To our knowledge, this key effect has not been reported elsewhere. At different shear rates, strength, Young's modulus and strain at break of PAN/CNT as-spun fibers were improved up to 20% compared to PAN fibers. Application of jet stretch had less influence on physical and mechanical properties of PAN/CNT fibers compared to PAN fibers. However, the improvement of interphase between polymer chains and CNTs as a result of chain orientation may have contributed to enhancement of Young's modulus of jet stretched composite fibers.

Keywords: PAN/CNT composite fibers; crystalline structure; elongation; mechanical properties; multi walled CNT; shear; wet spinning.