Abstract: A new chloro-substituted phthalazinone unit-containing aromatic diacid, 4-[3-chloro-4-(4-carboxy phenoxy)phenyl]-2-(4-carboxy phenyl)phthalazin-1-one(Ⅲ), was derived from the nucleophilic substitution of p-chlorobenzonitrile with the bisphenol-like monomer, 4-(3-chloro-4-hydroxy-phenyl)-2H-phthalazin-1-one(Ⅰ), followed by alkaline hydrolysis of the intermediate dinitrile, 4-[3-chloro-4-(4-cyano phenoxy)phenyl]-2-(4-cyano phenyl)phthalazin-1-one(Ⅱ). The structure of diacid Ⅲ was confirmed by FTIR, ¹H NMR, ¹³C NMR and MS. Moreover, ¹H and ¹³C NMR spectra of diacid Ⅲ were completely assigned by the two-dimensional NMR, such as gCOSY, gHMBC and gHSQC spectra. Using triphenyl phosphate(TPP) and pyridine as the condensing agents, a series of poly(aryl amide)s with inherent viscosities in the mass concentration range of 0.38—1.23 dL/g were prepared by the direct polycondensation of diacid Ⅲ with various aromatic diamines. Thus, the twisted, non-coplanar and unsymmetrical phthalazinone moieties were successfully introduced into the polymer main chain by the polycondensation method. All the poly(aryl amide)s containing chloro-substituted phthalazinone moieties were amorphous in nature, as evidenced by X-ray diffraction. Most of the poly(aryl amide)s were quite soluble in a variety of organic solvents, such as N-methyl-2-pyrrolidone(NMP), N,N-dimethylacetamide(DMAc), N,N-dimethylformamide(DMF) and dimethylsulfoxide(DMSO), and even in pyridine and m-cresol. All the resultant poly(aryl amide)s could be cast into transparent and tough films, indicating the feasibility of processing for application. The glass-transition temperatures of the polymers were determined by DSC method and they were in the temperature range of 291—332 ℃. These poly(aryl amide)s had useful levels of thermal stability associated with 10% mass-loss in excess of 460 ℃ in nitrogen, determined by TGA.

Key words: Phthalazinone, Poly(aryl amide), Polycondensation, Thermal stability