Detailed study of the ring‐opening metathesis polymerization of norbornene bearing a five‐ or six‐membered ring cyclic carbonate along with volume expansion

Abstract

AbstractThe ring‐opening metathesis polymerization (ROMP) of norbornene derivatives bearing five‐ or six‐membered cyclic carbonate (2 or 3) was carried out with a typical ruthenium catalyst [bis(tricyclohexylphosphine)benzylidene ruthenium(IV) dichloride], the so‐called first‐generation Grubbs catalyst, under various reaction conditions, to smoothly obtain the corresponding polyalkenamers (5 and 6) along with volume expansion. The number‐average molecular weights (Mn's), 10% weight loss decomposition temperatures, glass‐transition temperatures (Tg's), and volume expansion ratios of the resulting products depended on the polymerization conditions. The degree of volume expansion was mainly affected by Mn, Tg, and the cis/trans configuration of the exocyclic double bonds of the resulting polymers. The volume expansion was confirmed to specifically occur during the polymerization of the monomer bearing cyclic carbonate moieties, and similar ROMPs of monomers without cyclic carbonate, such as norbornene itself, the monomer 5,5‐bis(methoxymethyl)bicyclo[2.2.1]hept‐2‐ene, and the monomer endo‐N‐methylbicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylimide, proceeded along with volume shrinkage. Furthermore, an investigation of another type of polymerization, a vinyl‐type one, of monomer 2 suggested that the volume expansion specifically took place in the ring‐opening type of polymerization. In addition, the Sc(OTf)3‐mediated cationic ring‐opening reaction of the cyclic carbonate moiety of polyalkenamer 5 smoothly proceeded along with volume expansion or nearly zero volume shrinkage to yield the corresponding networked polymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 395–405, 2006