T. A. Antonova

Thermal analysis as a method of investigation of polymer-polymer interaction

Abstract The method of pyrolysis gas chromatography and thermovolumetric thermal analysis has been used for the investigation of polyamic acid-poly- N -vinylpyrrolidone and polyinude-poly- N -vinylpyrrolidone mixtures in helium. The products of thermal degradation have been identified. Data of analysis of gaseous and liquid degradation products for individual polymers and mixtures indicate that the mechanism of thermal degradation of polyimide changes when poly- N -vinylpyrrolidone is introduced into the mixture. This change is caused by the existence of the polymer-polymer interaction between the components of the mixture.

Solid-phase chemical reactions during the cyclodehydration of polyamic acids

The mechanical properties have been compared of polyamic acid (PAA) fibre samples based on the pyromellitic acid anhydride and 4,4-diaminophenyl ester when heated (tensile strength, elongation at break, linear macro-dimension), also the Mn which was estimated from the IR-spectral data; the rate of thermal-oxidative degradation was determined and the mechanism of the synthesis and macromolecular decomposition during the solid-phase thermal dehydration have been analyzed.

The thermal stability of sulphur-containing polypyromellitimides

The thermo-oxidative stability of a range of polypyromellitimides containing sulphur atoms in the diamino component, in the form of −S−, −S−S− and −SO2−bonds as well as mixed oxygen- and sulphur-containing fragments, has been determined by the TGA method. The relatively high thermal stability of sulphur derivatives in comparison with their oxygen containing analogues was demonstrated. The influence of the separation between neighbouring nitrogen atoms of the imide ring on polymide thermal stability is noted.