Novel aromatic poly(ether ketone)s. Part 2.—Synthesis and thermal properties of poly(ether keto amide)s

Abstract

Three groups of poly(ether keto amide)s have been prepared from terephthalic (TERE), isophthalic (ISO) and sebacic (SB) acids condensed with six diamines containing four and five benzene rings linked together by ether and ketone groups. The polymers proved to be soluble in dipolar aprotic solvents and could, in principle, be processed more easily than current commercially available aromatic polyamides. The thermal properties (T_g, T_m and decomposition temperature) of each have been evaluated, and the effect of the size of the diamine component and the use of meta versus para linkages examined. Rigorous evaluation of the data was hindered by a significant dependence of the thermal properties on the molecular weight (as measured by inherent viscosity, IV) of the polymers. However, the T_g of polymers was found to lie between that of simple polyarylamides and simple poly(aryl ether ketone)s, and to fall as the aryl ether and ketone content of the polymer increased. The polymers prepared with SB had lower T_g values, as expected from their aliphatic content, and likewise was significantly lower for the polymers from SB.