Five kinds of PAN with different molecular weight were polymerized via DMSO/H

2

O mixed solvent method

and the PAN was dissolved into the spinning solution with DMF as solvent and electrospun into UFFMs. The polymerization results showed that viscosity average molecular weight and conversion rate of PAN would increase with higher H

2

O ratio in mixed solvent at the same monomer concentration and environment conditions. From the TG analysis

dramatic weight loss zone would appear and the weight loss ratio would larger with PAN molecular weight increasing. Electrospinning results showed that the spinning solution could not be electrospun into ultra-fine fiber if the molecular weight of PAN was too high

and the higher electrospinning voltage was favorable for finer fiber diameter but cause larger dispersion of fiber diameter distribution with the electrospinning stability decreasing.