Improved solubilization of pyromellitic dianhydride and 4,4′-oxydianiline in ionic liquid by the addition of zwitterion and their polycondensation
作者:Masahiro Tamada、Takahiro Hayashi、Hiroyuki Ohno
DOI:10.1016/j.tetlet.2007.01.012
日期:2007.2
for polyimide synthesis. The solubility of 4,4′-oxydianiline and pyromellitic dianhydride as starting materials in ionic liquids was first evaluated, and then their polycondensation was carried out. Although these starting materials were hardly soluble in 1-benzyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (3), addition of imidazolium type zwitterion, 1-(1-butyl-3-imidazolio)butane-4-sulfonate
制备了三种不同的离子液体,并将其用作聚酰亚胺合成的溶剂。首先评估了4,4'-羟基二苯胺和均苯四甲酸二酐在离子液体中的溶解度,然后进行了缩聚反应。尽管这些原料几乎不溶于1-苄基-3-甲基咪唑双(三氟甲烷磺酰基)酰亚胺(3),但添加咪唑类两性离子,1-(1-丁基-3-咪唑并)丁烷-4-磺酸酯(ZI) ,当然提高了它们的溶解度。当使用含有40mol%ZI的3时,冷却至室温后,没有从该包含两种原料的混合溶液中相分离。在3中制备预聚物后在室温下,在含有40mol%的ZI的情况下,在相同的溶液中于100、200,然后300℃下每1小时进行缩聚,从而得到聚酰亚胺。所获得的聚酰亚胺(在10ml浓硫酸中为0.05g)的固有粘度为1.3dL g -1,高于仅在3个中所制备的特性粘度(0.9dL g -1)。聚酰亚胺较高的平均分子量归因于原料的溶解度的提高,这是因为添加了ZI,从而可以在酰亚胺化前不加热的情况下制备预聚物聚(酰胺酸)。