SYNTHESES AND THERMAL-PROPERTIES OF AROMATIC AND SEMIAROMATIC POLYTHIOETHERAMIDES CONTAINING OLIGO(THIO-1,4-PHENYLENE) SEGMENTS

A family of aromatic and semi-aromatic polythioetheramides was prepared from well-defined diamine-terminated oligo(thio-1,4-phenylene)s (PPS-DA) containing n=1,2,3,4,5,6 thio-1,4-phenylene units. Polycondensation reactions with adipic, sebacic, terephthalic and isophthalic acid chlorides were carried out in N-methyl-2-pyrrolidone solution at room temperature to yield amorphous and semi-crystalline polythioetheramides. The influence of the oligo(thio-1,4-phenylene) segment lengths on phase transitions and thermal degradation of the polythioetheramides was investigated. As a function of the PPS segment lengths, glass transition temperatures vary between 120-degrees-C and 300-degrees-C, and melting temperatures between 290-degrees-C and 500-degrees-C. The thermal stabilities determined by thermogravimetric analysis under nitrogen increase with increasing PPS segment lengths. In the case of the higher molecular weight PPS segments, the resulting semi-aromatic polyamides exhibit two crystalline phase transitions.