Controlled cationic alternating copolymerization of various enol ethers and benzaldehyde derivatives: Effects of enol ether structures. Issue 9 (17th February 2014)

• Record Type: Journal Article
• Authors: Ishido, Yasushi; Kanazawa, Arihiro; Kanaoka, Shokyoku; Aoshima, Sadahito
• Is Part Of: Journal of polymer science. Volume 52:Issue 9(2014:May)
• Page Start: 1334
• Page End: 1343
• Publication Date: 2014-02-17
• Subjects: acid hydrolysis -- alternating copolymerization -- benzaldehyde derivative -- cationic polymerization -- controlled polymerization -- degradation -- enol ether -- thermal properties; 547
• DOI: 10.1002/pola.27122
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: Significant structural effects of enol ether monomers were demonstrated in cationic alternating copolymerizations with benzaldehyde derivatives (BzAs). α‐Methyl, β‐methyl, β, β‐dimethyl, and cyclic enol ethers were copolymerized with BzAs by the EtSO3 H/GaCl3 system with 1, 4‐dioxane in toluene at −78 °C. β‐Methyl and cyclic monomers, β‐monosubstituted compounds, induced copolymerizations with BzAs, some of which were well controlled to yield alternating copolymers with controlled molecular weights (MWs) and narrow MW distributions. Conversely, an α‐methyl vinyl ether (VE) did not copolymerize with BzAs at all, probably due to its high reactivity and unfavorable ketal linkage formations. In addition, a β, β‐dimethyl VE underwent only cyclotrimerizations because of its larger steric repulsion. The product alternating copolymers, especially those with cyclic units, exhibited improved thermal properties compared to those with simple VEs units. Under appropriate conditions, the alternating copolymers selectively degraded into the corresponding cinnamaldehyde derivatives by acid hydrolysis. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1334–1343 Abstract : Various enol ethers were used as comonomers to reveal the effects of substituents at CC bonds on cationic alternating copolymerizations with benzaldehyde derivatives. Among α‐methyl, β‐methyl, and β, β‐dimethyl vinyl ethers (VEs) in addition to cyclic enol ethers used, β‐monosubstituted monomers, including cyclic compounds, successfully induced (controlled) alternating copolymerization. In contrast, α‐methyl and β, β‐dimethyl VEs induced VE homopolymerization and/or cyclotrimerization. Improved thermal properties and degradabilities with high selectivities of product alternating copolymers were also demonstrated.