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Updated: Sep 23, 2025

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Synthesis and characterization of new polyimides from diphenylpyrene dianhydride and ortho methyl substituted
R Sulub-Sulub1, M I Loría-Bastarrachea1, J L Santiago-García1
1Unidad de Materiales, Centro de Investigación Científica de Yucatán A. C., Calle 43 No. 130, Chuburná de Hidalgo, C. P. 97200 Mérida Yucatán México mjav@cicy.mx.
Abstract:
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 1H 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 CO2 permeability and a selectivity of 16 for CO2/CH4.
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