MOLECULAR MOTIONS IN A RIGID BACKBONE POLYMER - POLY(N-HEXYL ISOCYANATE) - A STUDY BY THERMALLY STIMULATED CURRENTS

The molecular motions of poly(n-hexyl isocyanate) have been studied sy stematically by the technique of thermally stimulated discharge curren ts (TSDC) in the temperature range -160-120 degrees C. Owing to the th ermal decomposition of the substance occurring at temperatures near 12 0 degrees C, it was not possible to extend the study to higher tempera tures and, particularly, it was not possible to study the molecular dy namics in the liquid-crystalline phase. In the studied temperature ran ge, a complex pattern of relaxation mechanisms was observed, which inc luded a low-temperature relaxation ascribed to the mobility of side-ch ain alkyl groups, the glass-transition relaxation (T-g = -50 degrees C ) and a higher temperature relaxation ascribed to the worm-like motion s of the polymer backbone.