Four kinds of copolymerized polyimide (PI) membranes were prepared through thermal imidization method after solution polymerization between two kinds of self-made diamine monomers 9,9′-bis[4-(4-amino-3-hydroxyphenoxy) phenyl] fluorene (BAHPPF) and 4-(4′-tertbutyl)phenyl-2,6-di(4′-aminophenyl)pyridine (TPAPP) and 4,4′-(hexafluoroisopropene)phthalic anhydride (6FDA), and the molar ratio of BAHPPF and TPAPP is 9∶1, 8∶2, 7∶3, and 6∶4, respectively. Then the corresponding copolymerized thermal rearrangement (TR) membranes were obtained after heat treatment at 450℃. The thermal, mechanical, and gas separation properties of the membrane materials were measured. The results show that the glass transition temperature of the copolymerized PI membranes is around 350℃. As the molar ratio of TPAPP increases, the tensile strength of the copolymerized PI membranes decreases. After thermal rearrangement, the mechanical properties of the copolymerized TR membranes decrease significantly, while the d values increase. When the molar ratio of BAHPPF and TPAPP is 8∶2, the copolymerized TR membrane exhibits the best gas permeability, and the permeation coefficients for H2, CO2, O2, and N2, is 346.4, 304.5, 72.43, and 13.34 Barrer respectively. Meanwhile, the O2/N2 separation performance of the four TR membranes is close to the Robeson upper limit in 2008.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |