Relative heat-stability of polydiphenylene phthalide, brominated polydiphenylene phthalide and polydiphenylene-N-phenylphthalimidine

摘要

Of the wide range of synthesised polyarylene phthalides, the most promising for practical use as a polymer is polydiphenylene phthalide (I)(refs. 1-3).As has been previously demonstrated, the heat stability ofp olydiphenylene phthalide is limited by the stability of the phthalide group (ref.4). Consequently, we modified this polymer (the lactone cycle) and obtained several new polyheteroarylenes-polydiphenylene-N-phenylphthalimidines (with both substituted and non-substituted nitrogen atoms)with more stable bonds than C-O,C-N) (refs.5-6). Direct halogenation I was used to synthesise polyarylene phthalides substituted in the benzene nucleus which are more thermally stable and fire resistant than the original polyarylene phthalide (ref.7). The most thermally stable of the nitrogen-containing polyheteroarylenes is polydiphenylene-M-phenylphthalimidine (III) (ref. 8) and the most thermally stable of the halogenated polyarylene phthalides is brominated polydiphenylene phthalide (II) (ref.7).