Gas Permeation Properties of Soluble Aromatic Polyimides Based on 4-Fluoro-4,4'-Diaminotriphenylmethane

Materials

Alberto Galicia-Aguilar¹  Jorge Froylán Palomeque-Santiago²  Javier Guzmán²  Diego Guzmán-Lucero²  Carla Aguilar-Lugo³  Claudia Camacho-Zúñiga⁴  Francisco Alberto Ruiz-Treviño⁴ 

[1] Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla,14 sur y San Claudio, Ciudad Universitaria, 72592 Puebla, Pue., Mexico;Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte 152, 07730 México, Mexico;Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito exterior s/n, Cuidad Universitaria, 70360 México, Mexico;Universidad Iberoamericana, Departamento de Ingenierías. Prol. Paseo de la Reforma No. 880,Col. Lomas de Santa Fe, C. P. 01219 México, Mexico;

关键词: polyimides;    4-fluoro-4'-4"-diaminotriphenylmethane;    gas separation membranes;   

DOI  :  10.3390/ma8041951

来源: DOAJ

【 摘 要 】

A series of new organic polyimides were synthesized from4-fluoro-4'4"-diaminotriphenylmethane and four different aromatic dianhydrides through a one-step, high-temperature, direct polycondensation in m-cresol at 180–200 °C, resulting in the formation of high-molecular-weight polyimides (inherent viscosities ~ 1.0–1.3 dL/g). All the resulting polyimides exhibited good thermal stability with initial decomposition temperatures above 434 °C, glass-transition temperatures between 285 and 316 °C, and good solubility in polar aprotic solvents. Wide-angle X-ray scattering data indicated that the polyimides were amorphous. Dense membranes were prepared by solution casting and solvent evaporation to evaluate their gas transport properties (permeability, diffusivity, and solubility coefficients) toward pure hydrogen, helium, oxygen, nitrogen, methane, and carbon dioxide gases. In general, the gas permeability was increased as both the fractional free volume and d-spacing were also increased. A good combination of permeability and selectivity was promoted efficiently by the bulky hexafluoroisopropylidene and4-fluoro-phenyl groups introduced into the polyimides. The results indicate that the gas transport properties of these films depend on both the structure of the anhydride moiety, which controls the intrinsic intramolecular rigidity, and the 4-fluoro-phenyl pendant group, which disrupts the intermolecular packing.

【 授权许可】

Unknown