| STUDY |
Authors used a copper(I) catalyst dissolved in an ionic liquid for the living polymerization of methyl methacrylate and showed that the poly(methyl methacrylate) product is essentially free of copper. A living polymerization is one with no termination reactions or in which termination is slow relative to chain growth. Such polymerizations allow highly branched functionalized macromolecules to be prepared with accurately controlled molecular architectures and narrow molecular weight distributions. "Our paper reports the first controlled polymerization in an ionic liquid," authors says. Authors are developing living and other controlled free-radical polymerization routes for the preparation of polymers for use in coatings, drug delivery, personal care products, contact lenses, and other applications. "The use of transition metals such as Cu(I) to mediate living polymerizations is rapidly being developed," author continues. "Our Cu(I) catalyst systems employ Schiff base ligands, which allow us to prepare polymers with narrow polydispersities, block copolymers, and star polymers with various functionalities without the need for protecting-group chemistry." Working with ionic liquids authors showed that the rate of methyl methacrylate polymerization is enhanced when the catalyst, Cu(I)-N-propyl-2-pyridylmethanimine, is dissolved in the room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6]. The polymer product is easily extracted from the ionic liquid reaction solution using toluene, a solvent that is immiscible with the ionic liquid and the catalyst. The team points out that previous polymerizations in ionic liquids, such as the Ziegler-Natta polymerization of ethylene and the oligomerization of butene, have employed water-sensitive chloroaluminate(III) ionic liquids. Polymerization of methyl methacrylate in [bmim][PF6], an air- and water-stable ionic liquid, is the first example of the use of a nonhygroscopic ionic liquid for polymerization, according to the team. Authors are now aiming to optimize the process & its potential to recycle the recovered ionic liquid-catalyst mixt. |
| UPDATE | 07.00 |
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