Polyacrylonitrile-MV500000

Catalog	ACM25014419-9
CAS	25014-41-9
Structure
Molecular Weight	500000
Storage	Room temperature

Case Study

Stabilization of Polyacrylonitrile Fibers with Carbon Nanotubes

Lu, Mingxuan, et al. Polymer Degradation and Stability, 2021, 188, 109567.

In this work, carbon nanotubes (CNTs) were used to accelerate the reaction rate and shorten the PAN stabilization time, and two-component core-sheath PAN-PAN/CNT fibers and single-component PAN/CNT fibers were fabricated. The stable △H_reaction of CNT in air was improved by 3 times compared to the control PAN fibers. At 250°C, the core-sheath PAN-PAN/CNT fibers were fully stabilized in less than 2 hours, while PAN with comparable fiber diameter required about 6 hours.
Fabrication of PAN-PAN/CNT fibers
· PAN-PAN/CNT fibers: The core component solution consisted of PAN (Mv =247,000 g/mol) dissolved in dimethylformamide (DMF). The sheath component solution (10 wt% CNT + 90 wt% PAN of Mv =247,000 g/mol) was a dispersion of PAN and carbon nanotubes (CNTs) in DMF. The CNTs were first dispersed in DMF through sonication before being added to the PAN solution. The core-sheath fibers were made using a bi-component fiber spinning unit. The as-spun fibers were drawn in a glycerol bath to enhance their mechanical properties, and were then coagulated in a methanol bath and subsequently drawn in a glycerol bath.
· Single-component PAN/CNT fibers: Single component PAN/CNT (90 wt% PAN + 10 wt% CNT, referred to as PAN/CNT-3) fibers were spun from different PAN/CNT solutions with a PAN Mv of 500,000 g/mol and a solid content of 9 g/dL in DMF. The solutions and fiber spinning were prepared following the same process mentioned previously.

Plasma and KMnO4 Oxidative Stabilization of Polyacrylonitrile Nanofibers

Mortazavi, S. Hamideh, et al. Molecular Crystals and Liquid Crystals, 2014, 592(1), 115-122.

The effects of plasma (10%, 20%, and 30% oxygen content) and chemical methods (3% and 5% KMnO4 content) on the stabilization of polyacrylonitrile (PAN) nanofibers prepared by electrospinning technology were investigated. The average fiber diameters decreased from 377 nm in PAN nanofibers to 180, 150, and 130 nm in oxidized fibers under 10%, 20%, and 30% oxygen, respectively. Additionally, they decreased to 288 and 220 nm under 3% and 5% KMnO4. Results show that the plasma stabilization proved far more effective and faster than chemical stabilization.
Oxidative stabilization process
· Chemical Stabilization by KMnO4 Solution: PAN samples were chemically stabilized by immersing them in a KMnO4 solution and heating them to 180-300°C for over an hour. This process converted C≡N bonds to C=N bonds and introduced new functional groups. However, excessive heating and high catalyst concentrations can damage the polymer.
· Low-Pressure DC Plasma Treatment: A Pyrex cylinder with two electrodes was used as a plasma reactor. PAN samples were placed at the bottom of the chamber and treated with oxygen plasma for 15 minutes at various oxygen concentrations (10%, 20%, 30%). While plasma treatment did not alter the bulk properties of the polymer, it did modify the surface by breaking C-H and CH2 bonds and creating free radicals. These radicals interacted with ambient oxygen, forming oxygen-containing groups (carbonyl, carboxyl) that increased the polymer's surface polarity.