SYNTHESIS AND CHARACTERIZATION OF HALOGEN-CONTAINING POLYISOPHTHALAMIDES

Two sets of aromatic polyamides were prepared from m-phenylenediamine (MPD) and 4,4'-diaminodiphenyl sulfone (DDS) in combination with a set of new halogenated diacyl chlorides, namely, 5-fluoroisophthaloyl chl oride, 5-chloroisophthaloyl chloride, 5-bromoisophthaloyl chloride and 5-iodoisophthaloyl chloride. The polymers were synthesized in high yi elds and in high molecular weight (as determined by gel permeation chr omatography) by means of the low temperature condensation method. Noti ceable changes in the spectral characteristics of the halogen-modified polyisophthalamides were observed compared to those of the correspond ing unmodified polyisophthalamides. Slight improvements were observed for the glass transition temperatures, which increased 5-30 degrees C relative to those of the conventional polyisophthalamides. Moreover, a correlation was found between the size of the halogen substituents an d the increase in T-g values. Thermogravimetric analysis showed that t he new polymers are almost as thermally resistant as the unmodified on es, while solubility in organic solvents was somewhat poorer.