基于5,5′-双[P-(4-氨基苯氧基)苯氧基]联嘧啶聚酰亚胺的合成及性能

Syntheses and Properties of Polyimides Derived from 5,5′-Bis[p-(4-Amino) Phenoxy] Bipyrimidine

氢碘酸、2-氯-5-溴嘧啶、对苯二酚以及对溴硝基苯等为原料,通过碘代、Ullmann、Williamson以及还原等反应合成了5,5′-双[P-(4-氨基苯氧基)苯氧基]联嘧啶,用元素分析,IR和1H-NMR等手段对化合物的组成和结构进行了表征。这种二胺与联苯四酸二酐(BPDA)通过两步法聚合获得含联嘧啶单元的聚酰亚胺,通过红外、差示扫描量热仪(DSC)和热重分析等实验测试了该类聚合物的结构、热性能、力学性能及结晶性能。新型聚酰亚胺分子结构单元中多个醚键以及联嘧啶单元氮杂原子的极性综合作用,使其玻璃化转变温度达到262℃,具有较好的热稳定性。

5,5′-bis [p-[（4-amino）phenoxy] phenoxy]bipyrimidine was synthesized from 2-chloro-5-bromo-pyrimidine,hydriodic acid,hydroquinone and 1-bromo-4-nitrobenzene via iodide reaction,Ullmann reaction,Williamson reaction,followed by a reduction process using hydrazine as reductive agent and Pd/C as catalyst.The as-synthesized compound was characterized by using elemental analysis,IR and 1H-NMR.Polyimides containing bipyrimidine units were prepared from the diamine and biphenyl dianhydride（BPDA） via a conventional two-step thermal imidizaton method.The structure,thermal performance,mechanical properties and crystallization properties of polyimides were characterized by the means of Fourier transform infrared spectra（FT-IR）,thermogravimetric analysis（TGA） and differential scanning calorimetry calorimeter（DSC）.The results show that comprehensive effect of multiple ether bond and nitrogen atoms polarity of bipyrimidine unit in the new polyimide makes glass transition temperature up to 262 ℃,indicating this polyimides have high thermal stability.