Anionic Polymerization IX: A Review of the Use of Crown Ether as a Modifier in the Anionic Polymerization and Copolymerization of Diene

Abstract

Ever since Petersen reported the complexing ability of the crown ether with alkali, alkaline earth and other cations, crown ether became a major subject for researchers. This is due to the fact that crown ether possesses the ability to form complexes with a variety of inorganic salts and also the ability to solubilize these salts in aprotic solvents. The complexation between metal cation and crown ether is believed to involve ion-dipole interactions and therefore is similar in nature to ordinary solvation. In addition, crown ether/metal cation complexes can serve as catalysts in reactions involving ionic intermediates. Polymerization of diene with crown ether/metal cation complexes is a typical example of this subject, since this reaction involves ionic intermediates. The detailed information including a brief history, chemical properties of crown ether and its application in the anionic polymerization and copolymerization have been discussed.