A series of aromatic copolyamides were prepared from（1,2-dihydro-2-（4-aminophenyl）-4-[4-（4-）（aminophenoxyl）phenyl）]phthalazin-1-one（DHPZ-DA）,p-phenylenediamine（PPD）,1,4-bis（4-aminophenoxy） benzene（BAPOB） and terephthaloyl dichloride by low temperature solution polycondensation.The polymers had relatively high inherent viscosities ranging from 1.74 dL/g to 4.31 dL/g.The polymers exhibit improved solubility in polar aprotic solvents with or without the addition of LiCl because of the introduction of twisted non-coplanar phthalazinone moieties and flexible ether linkages.The polymers had high thermal stability.Their glass transition temperature（Tg） values were in the range of 291～351℃,and the 5% and 10% weight loss temperatures in nitrogen were in the range of 486～504℃ and 509～528℃,respectively.WAXD measurements indicated that these copolyamides were amorphous.Most of the polymers exhibited lyotropic liquid crystalline characteristics in conc.H2SO4,NMP/（10 g/L LiCl） and DMAc/（10 g/L LiCl） solutions.The polyamides with excellent properties made it possible for the different processing and applications such as dry-wet spinning of fibers or the preparation of films,membranes and coatings.
