Preparation Of Amino Acid-based Poly(Ionic Liquid)s And Performance Of Their Sorbent Materials

Poly?amino acid-based ionic liquids?with controllable molecular weight and narrow molecular weight distribution were synthesized by atom transfer radical polymerization?ATRP?.Due to the coordination ability of amine and carboxylic groups,poly?amino acid-based ionic liquid?based-metal complexes were prepared,and the CO₂ absorption performances of PILs and their complex were studied.Amino acid-grafted PVBTMA-co-DVB porous materials were also developed and further study.of the properties and the CO₂ absorption performance of these porous materials were also included.Firstly,poly[2-?ethacryloyloxy?ethyl]trimethylammonium chloride?P[META][Cl]?with controllable molecular weight was synthesized in a mixture medium of water and DMF by atom transfer radical polymerization?ATRP?at 30?,using[2-?methacryl-oyloxy?ethyl]trimethylammonium chloride?METAC?as monomer,ethyl?-bromoisobutyrate as initiator,2,2-bipyridyl?bpy?and CuBr2 as catalyst and ascorbic acid as reductant.These chemical structure and physical/chemical properties of these polymers were characterized by nuclear magnetic resonance?1H-NMR?,size exclusion chromatography?SEC?,Thermogravimetric Analysis?TG?.In the system of vinylbenzyl trimethylammonium chloride?VBTMA?as monomer,N,N,N,N,N-pentamethyl diethylene triamine?PMDETA?with higher activity as a ligand could significantly improve the conversion of monomers.In order to improve the CO₂ absorption capacity of PILs,various of amino acid such as Aspartate?Asp??Glycine?Gly?and Histamine?His?as anion was introduced into the polymeric quaternary ammonium as cations.P[VBTMA][Asp]had the largest BET specific surface area?23 m2/g?because of its internal crosslinking structure.The effect of anions on the glass transition temperatures?Tg?of PILs of P[VBTMA][AA]demonstrated the following order:Asp>Gly>His?119?,83?,29??.The results showed that the CO₂ absorption capacity of PILs increase 2?8 times after introducing amino acid as anion,and P[VBTMA][Asp]had the highest CO₂ absorption capacity of 7.23 wt%.Furthermore,the formed poly?amino acid-based ionic liquid?s demonstrated not only chemical absorption of CO₂,but also physical adsorption and can be recycled through TG and BET measurement.Based on the principle of complex formation between amino acid and transition metal elements,we also developed novel adsorption material prepared with poly?amino acid-based ionic liquid?s and cupric ions.Using P[VBTMA][Gly]as an example,which can complex with cupric ions at a molar ratio of 4:1,a micron fibers with a diameter of 1?2 um,length of 20?100 um was fabricated in the mixture medium of water and ethanol.It showed that the CO₂ absorption capacity of complex is mainly affected by the type of amino acid and the ratio of cupric ion and amino acid.The complex of P[VBTMA][Asp]-Cu?8:1?has the highest CO₂ uptake?4.5 wt%?under TG measurement.The complex P[VBTMA][Asp]-Cu?4:1?has a adsorption capacity up to 16 wt%in I bar,273K and it is mainly physical adsorption,comparing the results of CO₂ absorption/adsorption between TG and BET measurement.Porous PVBTAM-co-DVB materials were also synthesized with methanol as porogen.It found that the content of the crosslinking agent had a certain influence on the degree of crosslinking.While the content of DVB was 5%,the porous material had the maximum degree of crosslinking?96%?.Pore structure of the material was also affected by solid content and post-treatment methods,PVBTAM?40 wt%?-co-DVB?5 wt%?demonstrated the largest BET specific surface area?31 m2/g?.After grafting amino acid by ion exchange,the PVBTAM?40 wt%?-co-DVB?5 wt%?sorbent showed an improved CO₂ absorption capacity.In this paper,poly?quaternary ammonium?polymers with controllable molecular weight and narrow distribution capacity were synthesized and a series of solid material with high CO₂ absorption were fabricated.These materials present a simply synthesis and significant high CO₂ uptake,which has great potential in the application in gas separation fields.