Study of the reactions of synthesis of soluble polyimides containing oligodimethylsiloxane fragments

Abstract

IR spectroscopy in solution in the mixture N-methylpyrrolidone-toluene at 298K has been used to study the kinetics of the reaction of the dianhydrides of 1,3- bis-(3,4-dicarboxyphenoxy)benzene and 3,3′,4,4′-benzophenone tetracarboxylic acid with the diamines—4,4′- bis-(4″-aminophenoxy) diphenylsulphone and α, ω- bis-( γ-aminopropyl) oligodimethylsiloxane with the number of siloxane units equal to ten. It is shown that passage from the aromatic tetranuclear diamine to α, ω- bis-( γ-aminopropyl) oligodimethylsiloxane and also from N-methylpyrrolidone to the N-methylpyrrolidone-toluene mixture raises the acylation rate constant. In N-methylpyrrolidone-toluene solution at 393 K a comparative study was made of the kinetics of cyclization of the o-carboxyamide units of two types: containing at the amide nitrogen atom the aromatic tetranuclear diamine radical or a fragment of propyl oligodimethylsiloxane. From the mixtures of these diamines and the dianhydride of 1,3- bis-(3,4-dicarboxyphenoxy)benzene copolyimides were obtained and their physicomechanical properties evaluated. The microstructure of the copolymers formed was investigated by 13C NMR spectroscopy.