Synthesis of Poly(norbornene ester)s by Using (eta(3)-substituted ally!) Palladium (NHC) Complex as Catalyst and Investigation of Their Chemical Structure - Glass Transition Temperature - Refractive Index Relationships

摘要

The synthesis of poly(norbornene ester)s by using a (eta(3)-substituted allyl) palladium (N-heterocyclic carbene (NEC)) complex as catalyst was performed and the relationship between chemical structure and glass transition temperature or refractive index of poly(norbornene ester)s was investigated. Norbornene ester monomers were synthesized via esterification of 5-norbornene-2-methyl alcohol and aromatic carboxylic acids. The polymerization catalyst, (eta(3)-substituted allyl) palladium (NHC) complex, was synthesized according to a published procedure. H-1-NMR spectroscopy was performed to determine chemical structure of monomers and polymers. The molecular weight of the polymers was measured via gel permeation chromatography and the thermal properties were analyzed via thermogravimetric analysis and dynamic mechanical analysis. Refractive indices of polymer films were measured using a prism coupler. Polymers with the highest M-n (between 100 kg/mol and 300 kg/mol) were synthesized when the ratio of monomer to catalyst was 2000:1. The glass transition temperature of synthesized polymers was about 100 degrees C lower than that of conventional norbornene polymers. Among the six polymers of different chemical structures, four polymers exhibited a refractive index of 1.6 or more at a wavelength in the visible light region.