Effects of the Swelling of Polyacrylonitrile Films in Various Aqueous Solutions on Their Reaction with Hydrazine

Abstract

Swelling behaviors of polyacrylonitrile (PAN) films in various aqueous solutions, such as N,N'-dimethylformamide (DMF)/water, N,N'-dimethylacetamide (DMAc)/water, dimethylsulfoxide (DMSO)/water, NaSCN or KSCN solution, the effects of the concentrations of these solutions, and the effects of swelling temperature and time on the degree of swelling of PAN films were analyzed. Among the various aqueous solutions, DMF and NaSCN solution were found to be effective for high swelling of PAN films. High swelling of PAN films in the hydrazine solutions wherein aqueous, organic solvents or salt solutions were used as solvents for hydrazine, resulted in higher absorption of hydrazine and a high degree of cross-linking. Analysis of the bands of FT-IR spectra and the cyclization peaks of DSC curves for various hydrazine-treated PAN films showed that the effective cross-linking of PAN films at the same hydrazine concentration was obtained by using DMF/water or NaSCN/water solutions as solvents for hydrazine and treating medium for PAN films.