9位芳香基取代超支化聚芴的合成与表征

以2,7-二溴芴酮为起始原料,在芴的9位引入芳香取代基代替传统的烷基取代基,增加9位的稳定性,并用AB+AB2的方法,用新单体合成了不同支化度的超支化聚合物,新合成的超支化聚合物具有良好的热稳定性和发光稳定性.聚合物的热分解温度都在400℃以上;聚合物的薄膜在空气中于200℃加热2 h后没有出现绿光发射带,发光稳定性和烷基聚芴相比得到明显的提高.DSC结果显示,线性聚合物在170℃时有玻璃化转变,超支化聚合物在300℃以内没有明显的相转变,保持一种稳定的无定形态,更有利于提高材料的发光效率.

Synthesis and Characterization of 9,9'-Diarylfluorene Hyperbranched Polymers

Starting from 2,7-dibromofluorene, two aryl substituents were introduced to the 9-position of fluorene to replace the commonly used alkyl groups so as to increase the stability of fluorene. New hyperbranched polymers that exhibited excellent thermal and luminescent stability were synthesized using newly designed monomers through the “AB2+AB” approach. The decomposition temperatures of all hyperbranched polymers are above 400 ℃. The polymer films heated at 200 ℃ in air for 2 h were not observed green emission band. Compared with alkyl substituted polyfluorenes, the luminescence stability has a marked improvement. DSC results show that linear polymers have a glass transition at 170 ℃, but hyperbranched polymers do not have an obvious phase transition under 300 ℃, indicating hyperbranched polyfluorenes form amorphous films, which help to improve the efficiency of PLEDs.