Fast step-growth polymerization of 5-(3-acetoxynaphthoylamino)isophthalic acid with different diisocyanates under microwave irradiation



The direct polycondensation reactions of diacid, 5-(3-acetoxynaphthoylamino)isophthalic acid with various aromatic and aliphatic diisocyanates such as 4,4'-methylene bis(4-phenylisocyanate), toluylene-2,4-diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate were carried out under microwave irradiation conditions. In order to compare this method with classical heating, the polymerization reactions were also performed under solution polycondensation conditions. The polymerization reactions occurred rapidly under microwave conditions and produced a series of polyamides containing pendent acetoxynaphthalamide group, with good yields and moderate inherent viscosities of 0.26-0.45 dL/g. The comparable yields and higher inherent viscosities were obtained by microwave irradiation versus thermal heating with substantial reduction in reaction time.