SYNTHESIS AND THERMAL-PROPERTIES OF POLY(AMIDEIMIDE)S BASED ON TRICARBOXYLIC-ACID ANHYDRIDES CONTAINING ARYLOXY GROUPS

Thermostable poly(amideimide)s (PAIs) were synthesized according to a 'one-pot/two-step' direct polycondensation of flexible aromatic diamin es with monoesters of isomeric tricarboxylic acid anhydrides containin g an aryloxy group or with the monoesters of trimellitic anhydride (TM A). The prepared PAIs have inherent viscosity values of 0.46-0.95 dl g (-1), are soluble in strongly polar aprotic solvents and form tough an d transparent films. The molecular structure of the polymers was inves tigated by Fourier transform infrared and H-1 and C-13 nuclear magneti c resonance spectroscopy. A constitutional disorder due to a random se quence of amide and imide groups was found. Measurements by wide-angle X-ray diffraction indicated that the prepared PAIs are amorphous. The thermal behaviour was studied by differential scanning calorimetry an d dynamic thermogravimetric analysis. The glass transition temperature s (T-g) of the PAIs obtained from monoesters of tricarboxylic acid anh ydrides containing an aryloxy group range between 262 and 213 degrees C, and are lower than those of the corresponding PAIs derived from TMA . The prepared PAIs have high thermal resistance in nitrogen as shown by their temperatures of 10% of weight loss (T-d), which are higher th an 500 degrees C. Both T-g and T-d depend on the orientation of the ar yloxy group in the tricarboxylic acid anhydride moiety. (C) 1997 Elsev ier Science Ltd.