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首页> 外文期刊>RSC Advances >Synthesis and characterization of new polyimides from diphenylpyrene dianhydride and ortho methyl substituted diamines
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Synthesis and characterization of new polyimides from diphenylpyrene dianhydride and ortho methyl substituted diamines

机译：由二苯基py二酐和邻甲基取代的二胺合成和表征新型聚酰亚胺

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摘要

Three new polyimides were synthesized via one-step polycondensation from 3,8-diphenylpyrene-1,2,6,7-tetracarboxylic dianhydride ( DPPD ) with two diamines with ortho methyl substitution ( MBDAM and HFI ) and one diamine without ortho substituents ( BAPHF ). The effect of diamine structure in DPPD based polyimides' physical, thermal, mechanical and gas transport properties has been studied. The polyimide structure was confirmed by FTIR and ~(1) H NMR. All polymers show high thermal stability with decomposition temperatures above 493 °C, and glass transition temperatures above 336 °C. Changes in packing density of polyimide membranes were assessed by wide angle X-ray diffraction and correlated to fractional free volume FFV. Polyimides based on rigid DPPD dianhydride exhibited an improved gas permeability and selectivity when ortho methyl substituents are present in the diamine used for polyimide synthesis. DPPD-MBDAM polyimide showed the best gas productivity values with 565 barrer CO _(2) permeability and a selectivity of 16 for CO _(2) /CH _(4) .
机译：通过3,8-二苯基py-1,2,6,7-四羧酸二酐（DPPD）与两个带有邻甲基取代的二胺（MBDAM和HFI）和一个没有邻位取代基的二胺（BAPHF）一步缩聚合成了三个新的聚酰亚胺）。研究了二胺结构对基于DPPD的聚酰亚胺的物理，热，机械和气体传输性能的影响。通过FTIR和〜（1）1 H NMR确认了聚酰亚胺的结构。所有聚合物均表现出高热稳定性，分解温度高于493°C，玻璃化转变温度高于336°C。通过广角X射线衍射评估聚酰亚胺膜的堆积密度的变化，并将其与自由体积分数FFV相关。当在用于聚酰亚胺合成的二胺中存在邻甲基取代基时，基于刚性DPPD二酐的聚酰亚胺表现出改善的透气性和选择性。 DPPD-MBDAM聚酰亚胺显示出最佳的气体生产率值，具有565 barrer的CO _（2）渗透率，对CO _（2）/ CH _（4）的选择性为16。

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