Synthesis and characterization of polyamides and poly(amide-imide)s derived from 2,6-bis(3-aminophenoxy)benzonitrile or 2,6-bis(4-aminophenoxy)benzonitrile

A series of polyamides and poly(amide-imide)s was prepared by direct polycondensation of ether and nitrile group containing aromatic diamines with aromatic dicarboxylic acids and bis(carboxyphthalimide)s respectively in N-methyl 2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. New diamines, such as 2,6-bis(4-aminophenoxy)benzonitrile and 2,6-bis(3-aminophenoxy)benzonitrile, were prepared from 2,6-dichlorobenzonitrile with 4-aminophenol and 3-aminophenol, respectively, in NMP using potassium carbonate. Bis(carboxyphthalimide)s were prepared from the reaction of trimellitic anhydride with various aromatic diamines in N,N'-dimethyl formamide. The inherent viscosities of the resulting polymers were in the range of 0.27 to 0.93 dl g(-1) in NMP and the glass transition temperatures were between 175 and 298degreesC. All polymers were soluble in dipolar aprotic solvents such as dimethylsulfoxide, dimethylacetamide and NMP. All polymers were stable up to 350 degreesC with a char yield of above 40 % at 900 degreesC in nitrogen atmosphere. All polymers were found to be amorphous except the polyamide derived from isophthalic acid and the poly(amide-imide)s derived from diaminodiphenylether and diaminobenzophenone based bis(carboxyphthalimide)s. (C) 2004 Society of Chemical Industry.