Polyacrylonitrile-MV150000

Catalog	ACM25014419-6
CAS	25014-41-9
Structure
Molecular Weight	150000
Storage	Room temperature

Case Study

High-Temperature Electrospinning Production of Polyacrylonitrile Nanofibers

Wang, Chi, et al. Macromolecules, 2007, 40(22), 7973-7983.

The effect of temperature on the resulting fiber morphology was investigated by electrospinning polyacrylonitrile/dimethylformamide (PAN/DMF) solutions of varying concentrations at temperatures ranging from ambient to 88.7 °C. The viscosity-average molecular weight (Mv) of polyacrylonitrile is 141400 g/mol, and DMF is a good solvent for PAN. A certain weight of polymer and solvent were mixed for several hours until a homogeneous solution was obtained for the electrospinning process.
It was found that the viscosity (ηo ) and surface tension (γ) of the PAN/DMF solution decreased with increasing solution temperature, but the solution conductivity (κ) increased. All these trends favor the development of finer electrospun PAN fibers at high electrospinning temperatures.
For example, PAN fibers with a diameter of 65-85 nm were easily prepared by electrospinning at 88.7 °C using a 6 wt % solution, while larger fibers with a diameter of 190-240 nm were typically obtained at room temperature.
Furthermore, in contrast to electrospinning at room temperature, the fiber diameter has a stronger dependence on viscosity, which is mainly due to the enhanced solution properties at high temperatures, namely, higher conductivity and lower surface tension.

Optimization of Stabilization Conditions for Electrospun Polyacrylonitrile Precursor Nanofibers

Wu, Meiyu, et al. Polymer degradation and stability, 2012, 97(8), 1511-1519.

In the process of making carbon nanofibers (CNF) from electrospun polyacrylonitrile (PAN) precursor fibers, optimization of processing conditions for thermal oxidation (stabilization) treatment of PAN precursor nanofibers is a key step.
· Electrospinning of PAN nanofibers
PAN (Mw=150,000 g/mol) was dissolved in DMF to prepare a clear solution. Subsequently, acetone and cetyltrimethylammonium bromide (CTAB) were added to it to prepare a spinning solution with a composition of 10wt.% PAN, 5wt.% acetone and 0.03wt.% CTAB for the electrospinning process under specific conditions.
· Optimal stabilization conditions
The optimal conditions for stabilization were determined to involve a thermal treatment ranging from 30 to 280 °C, at a heating rate of 2 °C/min while applying a constant load of 1 kN, followed by a 2-hour hold at 280 °C. Under these parameters, the processes of dehydrogenation and intra-cyclization were nearly completed, resulting in almost total destruction of the PAN crystal structure and the formation of a thermally stable ladder-like polymer structure. The nanofibers that were carbonized at 1000 °C exhibited electrical conductivity, which was significantly influenced by the stabilization conditions. The highest conductivity recorded was approximately 20.2 ± 1.2 S cm-1, achieved under the optimized conditions.