Selectively degradable alternating copolymers of isobutyl vinyl ether and plant-derived aldehydes with acyclic side chains: Effects of side group structures on copolymerization behaviors

ABSTRACT Side group structures of aldehydes were demonstrated to have decisive effects on cationic copolymerizations with alkyl vinyl ether (VE). Alternating copolymerizations of isobutyl VE (IBVE) and plant‐derived aldehydes with acyclic side chains such as trans‐2,cis‐6‐nonadienal, trans‐2‐nonenal, and citral proceeded under appropriate reaction conditions with the EtSO3H/GaCl3 initiating system. In addition, some aldehydes copolymerized in a well‐controlled fashion to yield alternating copolymers with controlled molecular weights and narrow molecular weight distributions. Quantitative and selective acid hydrolysis of the resulting alternating copolymers, based on the acetal structures in the main chains, was also achieved to give other conjugated aldehydes as nearly sole degradation products. Copolymerization results of IBVE and various plant‐derived aldehydes with acyclic or cyclic side groups suggested that electron‐donating ability and bulkiness of the side groups were most likely responsible for the alternating and/or controlled copolymerization behaviors. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4684–4693 Relationships between side group structures of plant‐derived aldehydes and their copolymerization behaviors with vinyl ether were investigated. Conjugated aldehydes were cationically copolymerized in alternating fashion, some of which were controlled to produce copolymers with well‐defined structures. The product alternating copolymers were selectively degradable by acid hydrolysis into other conjugated aldehydes. Judging from copolymerization results using various plant‐derived aldehydes with acyclic or cyclic structures, bulkiness and electron‐donating ability of side groups would be crucial for copolymerization behaviors.