New homopolymers and copolymers based on 5-succinyl cyclooctene and mono-substituted ethylene glycols

Abstract

New polyoctenamers containing ethylene glycol-based substituents at the 5th position were synthesized and characterized. Tetraethylene glycol methyl ether side groups decreased the water contact angle for a polymer film from 97° to 42°, whereas slightly longer pendants with 4 to 6 ethylene glycol units resulted in water-soluble polyoctenamer at room temperature with a cloud point at 40 °C. In addition to homopolymers, statistical multiblock and random copolymers of cyclooctene and 5-substituted cyclooctene were obtained on the same Grubbs’ catalysts of first to third generation. Multiblock copolymers were formed by macromolecular cross-metathesis between polyoctenamer and 5-substituted polyoctenamer. The mean block lengths can be regulated by adjusting the reaction time, blend composition, and catalyst-to-polymer ratio. The copolymers revealed crystallinity and a pronounced tendency for micellization in ethyl acetate, a poor solvent for unsubstituted octenamer blocks. Random copolymers resulted from ring-opening metathesis copolymerization. Although they possess higher molar masses than their corresponding multiblocks, it is difficult to control their composition due to the different comonomer reactivity. The present study opens new possibilities for tuning the thermal and amphiphilic properties of polyalkenamer-based copolymers.