Non-Coagulant Spinning of High-Strength Fibers from Homopolymer Polyacrylonitrile Synthesized via Anionic Polymerisation

The rheological properties, spinnability, and thermal-oxidative stabilization of high-molecular-weight linear polyacrylonitrile (PAN) homopolymers (molecular weights = 90-500 kg/mol), synthesized via a novel metal-free anionic polymerization method, were investigated to reduce coagulant use, enable...

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Bibliographic Details
Published in:Polymers 2024-05, Vol.16 (9), p.1185
Main Authors: Skvortsov, Ivan Yu, Kuzin, Mikhail S, Gerasimenko, Pavel S, Mironova, Maria V, Golubev, Yaroslav V, Kulichikhin, Valery G
Format: Article
Language:English
Subjects:
Analysis
Anionic polymerization
Carbon fibers
Coagulants
Coagulation
Deformation effects
Fiber orientation
Heat treatment
Humidity
Mechanical properties
Methods
Molecular weight
Phase separation
Polyacrylonitrile
Polymerization
Polymers
Rheological properties
Rheology
Solvents
Surface active agents
Tensile strength
Viscosity
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Summary:The rheological properties, spinnability, and thermal-oxidative stabilization of high-molecular-weight linear polyacrylonitrile (PAN) homopolymers (molecular weights = 90-500 kg/mol), synthesized via a novel metal-free anionic polymerization method, were investigated to reduce coagulant use, enable solvent recycling, and increase the carbon yield of the resulting carbon fibers. This approach enabled the application of the mechanotropic (non-coagulating) spinning method for homopolymer PAN solutions in a wide range of molecular weights and demonstrated the possibility of achieving a high degree of fiber orientation and reasonable mechanical properties. Rheological analysis revealed a significant increase in solution elasticity (G') with increasing molecular weight, facilitating the choice of optimal deformation rates for effective chain stretching prior to strain-induced phase separation during the eco-friendly spinning of concentrated solutions without using coagulation baths. The possibility of collecting ~80 wt% of the solvent at the first stage of spinning from the as-spun fibers was shown. Transparent, defect-free fibers with a tensile strength of up to 800 MPa and elongation at break of about 20% were spun. Thermal treatment up to 1500 °C yielded carbon fibers with a carbon residue of ~50 wt%, in contrast to ~35 wt% for industrial radically polymerized PAN carbonized under the same conditions.
ISSN:2073-4360
2073-4360
DOI:10.3390/polym16091185