Studies On Synthesis, Thermal Properties And Solubility Of Aromatic Polyamides Containing Phthalazinone Moiety

The synthesis process of unsubstituted phthalazinone-containing diamine was optimized, with the reaction time of reduction being decreased from 14 to 5 h, and the yield of diamine being increased from 82% to 91%. After the optimization of poly(phthalazinone amide) polymerization, the inherent viscosity of this polymer can reach 1.32 dL.g-1. Moreover, a new fluorinated phthalazinone-containing diamine was prepared, and a series of novel aromatic polyamides with fluorinated phthalazinone units were prepared from the diamine and aromatic dicarboxylic acids. These polymers have glass transition temperatures between 302-334℃ and 10% mass loss temperatures in the range of 486-493℃ in nitrogen. All the polyamides can be readily dissolved in polar aprotic solvents such as NMP, DMAc, m-cresol and pyridine.With the help of the molecular design, five new aromatic dicarboxylic diacids containing phthalazinone moiety were successfully synthesized via the aromatic nucleophilic substitution and alkaline hydrolysis. All absorptions of these compounds in their 1H and 13C NMR spectra were clearly and completely assigned. The phthalazinone-containing structures of the resultant diacids are confirmed by NMR and FT-IR spectra. The 3D model molecules of diacids, simulated using the Program of Chemical Office software version 8.0, show the kink and non-coplanar conformation of the diacids. Five series of poly(phthalazinone amide)s were successfully synthesized from these five diacids and commercial aromatic diamines by phosphorylation polycondensation, respectively. The effects of different substituents on the thermal and soluble properties of polyamides were studied in detail. These polymers have useful levels of thermal stability associated with relatively high glass-transition temperatures (280~355℃) and 10% mass loss temperatures in the range of 480-555℃ in nitrogen. All the polymers are readily soluble in many organic solvents such as NMP, DMAc, and m-cresol.A new bisphthazinone-containing dicarboxylic diacid was designed and synthesized. A series of novel aromatic polyamides were prepared from the diacid and commercial diamines. These polyamides show high thermal resistance (Tg=319-324℃) and good solubility in many organic solvents.The application of novel poly(phthalazinone amide)s in insulating coating wasexplored. The insulating coatings show high performance. The adhesion is 1 grade, and pencil hardness is 6 H. The surface resistance coefficients of insulating coatings are over 1014Ω, and the volume resistant coefficients of coatings are higher than 1015 Ω.cm. The main properties of poly(phthalazinone amide) enamel wires were better than 200 grade enamel wire. Both insulating coatings and enamel wires show good stability in strong acids, strong base and salt solutions.