共聚聚酰亚胺基热重排气体分离膜的制备与性能

Preparation and properties of copolymerized polyimide based thermally rearranged gas separation membranes

采用两种自制的二胺单体9,9′-双[4-(4-氨基-3-羟基苯氧基)苯基]芴(BAHPPF)和4-(4′-叔丁基)苯基-2,6-二(4′-氨基苯基)吡啶(TPAPP),分别以9∶1、8∶2、7∶3、6∶4的物质的量之比混合之后,与4,4′-(六氟异丙烯)二酞酸酐(6FDA)进行溶液聚合,通过热酰亚胺化法制备出4种共聚聚酰亚胺(PI)膜。然后经450℃热处理制得相应的共聚热重排(TR)膜。对膜材料的热性能、力学性能和气体分离性能进行了测试。结果表明:共聚PI膜的玻璃化转变温度约为350℃。随着TPAPP摩尔分数的增加,共聚PI膜的拉伸强度有所下降。热重排后,共聚TR膜的力学性能明显降低,但晶面间距d值显著增大。当BAHPPF与TPAPP物质的量之比为8∶2时,共聚TR膜的气体渗透性最好,对H_(2)、CO_(2)、O_(2)和N_(2)的渗透系数分别为346.40、304.50、72.43、13.34 Barrer。同时,4种TR膜的O_(2)/N_(2)分离性能均接近2008年的Robeson上限。

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 H_(2),CO_(2),O_(2),and N_(2),is 346.4,304.5,72.43,and 13.34 Barrer respectively.Meanwhile,the O_(2)/N_(2)separation performance of the four TR membranes is close to the Robeson upper limit in 2008.