Stabilization of polyacrylonitrile fibers with carbon nanotubes. (June 2021)

• Record Type: Journal Article
• Authors: Lu, Mingxuan; Arias-Monje, Pedro J.; Ramachandran, Jyotsna; Gulgunje, Prabhakar V.; Luo, Jeffrey; Kirmani, Mohammad Hamza; Meredith, Carson; Kumar, Satish
• Is Part Of: Polymer degradation and stability. Volume 188(2021)
• Publication Date: 2021-06
• Subjects: Nanocomposites -- Stabilization kinetics -- Carbon nanotubes; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2021.109567
• Languages: English
• ISSNs: 0141-3910

Abstract

Highlights: Stabilization was investigated for PAN/CNT fibers with single-component and core-sheath fiber geometry. CNT in the PAN/CNT was shown to increase the reaction rate and significantly reduce the time of PAN stabilization. 10 wt% CNT in polymer led to a porous structure before and after stabilization, which increased the oxygen diffusion, and hence the stabilization rate. Abstract: Stabilization is an energy-intensive and time-consuming step for making PAN-based carbon fiber. Here, a new pathway is shown that uses carbon nanotubes (CNT) to accelerate the reaction rate and to reduce the PAN stabilization time. Bi-component core-sheath PAN-PAN/CNT (10 wt% CNT) fibers and single-component PAN/CNT (10 wt% CNT) fibers were made. When comparing to PAN fiber with comparable diameter, the heat of stabilization ( Δ H r e a c t i o n ) of PAN/CNT fibers increased up to 3 times in the air, while it did not change in N2 . The addition of CNTs reduced the activation energy ( E a ) of PAN cyclization by up to 12% but increased it for the oxidation reaction by up to 80% compared to PAN fibers. CNTs did not increase the kinetic constant of the cyclization reaction but increased it for the oxidation reaction (koxidation ) by up to 5 times, when comparing to PAN fiber at 250°C. At the same temperature, the bi-component PAN/CNT fiber bundle was fully stabilized in less than 2 hours, while the PAN fibers with comparable diameter took 6 hours to stabilize. Porosity was observed in the PAN/CNT precursor as well as in the stabilized PAN/CNT. This porosity was considered, at least partially responsible for increased oxygen diffusion, and hence for the decrease in the PAN stabilization time.