Novel perfluorononenyloxy group containing aromatic polyamides

Abstract

A series of novel perfluorononenyloxy group containing aromatic polyamides were synthesized by direct polycondensation of 5-(perfluorononenyloxy)isophthalic acid ( I) with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) containing lithium chloride. In this process, triphenyl phosphite and pyridine were used as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide (DMAc), dimethyl sulfoxide, and N-methyl-2-pyrrolidone. Transparent and flexible films of these polymers could be cast from the DMAc solutions. The polymers having inherent viscosity of 0.81–1.42 dl g −1 were obtained in quantitative yields. These polymers were thermally quite stable. The glass transition temperatures of these aromatic polyamides were in the range of 275–308°C by d.s.c. and 282–319°C by d.m.a., and the 10% weight loss temperatures in nitrogen and air were above 498 and 488°C, respectively. Moreover, these polymers maintained good mechanical properties ( G′ ∼ 10 8 Pa) up to 280°C and had lower moisture absorption than common polyamides.