Effect of swelling on carbon dioxide adsorption by poly(ionic liquid)s

摘要

A two-step swelling method was used for preparing porous poly(ionic liquid)s based on the copolymer of 1-allyl-3-methylimidazolium tetrafluoroborate and acrylonitrile P([AMIM]BF _4-AN), the copolymer of 1-allyl-3-methylimidazolium hexafluorophosphate and acrylonitrile P([AMIM]PF _6-AN), and poly(vinylbenzyl trimethylammonium) tetrafluoroborate P[VBTMA]BF _4. The characteristics of the polymers were assessed via FT-IR spectroscopy, scanning electron microscopy (SEM) and CO _2 adsorption. The results indicated that the seed-swelling method was more effective in improving the CO _2 adsorption capacity of imidazolium-based P([AMIM]BF _4-AN) containing the [BF _4] ~- anion. Exchanging [B _4] ~- for [PF _6] ~- in the imidazolium-based poly(ionic liquid) led to almost the same CO _2 adsorption as exhibited by the corresponding non-swelling copolymer. Moreover, the CO _2 adsorption capacity of ammonium-based P[VBTMA]BF _4 when treated by the seed-swelling method decreased considerably.