Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization in Ionic Liquids: A Sustainable Process

Abstract

Ionic liquid (IL) is an important class of materials which have asymmetric organic cation and inorganic anion. Most of the ILs remain as liquids at ambient temperature and are non-toxic in nature. They have low-to-zero vapor pressure and high thermal stability and have the potential to replace many volatile organic solvents. They have several advantages over conventional solvents and are considered as ‘green’ solvents. In polymer science, they are used as solvents for polymerization as well as an additive in polymer processing. In this case, IL was used as the solvent for the polymerization of different acrylates via a reversible addition-fragmentation chain transfer (RAFT) process, a method of controlled radical polymerization. RAFT polymerization in IL was observed to be remarkably fast. The IL used in the polymerization process was successfully recovered and reused without any loss in efficiency or efficacy. It was also observed that the presence of even a small amount of IL can increase the rate of polymerization.