Polar Thermoplastics with Tunable Physical Properties Enabled by the Stereoselective Copolymerization of Vinyl Ethers

Abstract

A series of isotactic, semicrystalline vinyl ether copolymers (up to 94% <i>meso</i> diads) were synthesized using a chiral BINOL-based phosphoric acid in combination with a titanium Lewis acid. This stereoselective cationic polymerization enabled the systematic tuning of both glass transition (<i>T</i>_g) and melting temperature (<i>T</i>_m) in copolymers derived from alkyl vinyl ethers (i.e., ethyl, butyl, isobutyl). Additionally, a vinyl ether comonomer bearing an acyl-protected alcohol was utilized as a platform for postfunctionalization. Copolymers containing the masked alcohols were shown to undergo deprotection and subsequent coupling with a desired acid chloride. Collectively, these results highlight the diverse material properties and expanded chemical space accessible through stereoselective cationic polymerization mediated by a chiral anion.