Thermal Behavior of Aromatic Polysulfones with Pendent Viologen Groups

Abstract

Polysulfones with pendent diquaternary 4,4-bipyridinium groups are polysulfones containing pendent viologen groups. They were obtained by the reaction of chloromethylated polysulfones with N-monoquaternary-4,4′-bipyridinium bromides as: N-( p-H, NO2, Cl) phenacyl - 4,4′- bipyridinium bromides and N-carbomethoxymethyl/ethy l-4,4′-bipyridinium bromides (1a-e). The thermal stabilities of polysulfone with pendent viologen groups (2a-e) were investigated. The influence of the chemical structure of pendent viologen groups on the thermal stability was investigated by thermogravimetric analysis in the dynamic conditions of temperature and atmospheric air. The substituted compounds underwent a thermal degradation process that took place by a complex mechanism in three steps. These steps are discussed from points of view of both the kinetic parameters and the thermogravimetric characteristics. The thermostability of low molar mass compounds 1a-e decreased in following order: 1c < 1a < 1e < 1d <1b and the same thermostability order was found in the case of chloromethylated polysulfone derivatives 2a-e (2c < 2a < 2e < 2d < 2b).