Ring-opening metathesis polymerization of ester-functionalized endo-tricyclo[4.2.2.0(2,5)]deca-3,9-dienes and thermal properties of the resulting polymers

We investigated the ring-opening metathesis polymerization (ROMP) of readily preparable ester-functionalized tricyclo[4.2.2.0(2,5)]deca-3,9-diene (TDD) monomers, 4-oxa-endo-tetracyclo[5.4.2.0(2,6).0(8,11)]trideca-9,12-dien-3-one (1) and endo-endo-tricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,8-dicarboxylate (2), and disclose the thermal properties of the resulting polymers. The polymerizations of 1 and 2 proceed in a living fashion using Grubbs catalysts (first- and third-generation), and their ROMP rates were comparable with, or higher than, those of their norbornene (NB) derivatives. Poly1 and poly2 were amorphous in structure and found to be soluble in polar organic solvents. Owing to the bi- and tricyclic main chain polymer structures of poly1 and poly2, the glass transition temperatures of their copolymers with norbornene increased significantly, and linearly, with higher 1 and 2 content. Evolved gas analysis-gas chromatography/mass spectrometry studies suggested that the pyrolysis mechanism involves retro-Diels-Alder reactions.