Witold Brostow, Nandika Anne D'Souza, and Bhaskar Gopalanarayanan

Departments of Materials Science and Chemistry, University of North Texas, Denton, TX 76203-5310, USA

ABSTRACT

Blends of thermoplastic polyimide (TPI) and a polymer liquid crystal (PLC) were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The presence of PLC enhances orientation in the system and lowers the crystallization temperature - a manifestation of the channeling effect predicted theoretically. The degradation studies show high temperature stability of all blends with the degradation onset consistently above 520°C. The onset decreases with PLC concentration but reaches a plateau above 30 wt% PLC when the PLC-rich islands are formed. The amount of moisture absorbed decreases with the PLC concentration while the moisture does not affect the degradation of the samples significantly. A phase diagram is constructed for the PLC + TPI blends from the DSC and TGA data. A comparison of amorphous and semicrystalline TPI and the characterization of amorphous TPI + PLC blends will be reported later.

*Polymer Eng. Sci., 1998, 38, 204