Relationship between degree of polymerization and optical and thermal properties of fluorene in polycarbonate polymers

Abstract

ABSTRACTThe influences of average degree of polymerization (Dp) and terminal group on thermal and optical properties of high refractive indexed transparent polymers were investigated. In this study, 9,9‐bis[4–(2‐hydroxyethoxy) phenyl] fluorene (BPEF) homo polymer was selected because it has been used as a representative monomer in high refractive index polymers as well as its unique property. BPEF has stable amorphous phase and reacts like a polymer. Its unique reaction allows continuous investigation from monomer to polymer. For hydroxyl‐terminated polymer, the refractive index (nd) decreased with increasing Dp. On the other hand, for a phenolic‐terminated group, nd increased with increasing Dp, and both converged to same value in high Dp region. As for glass transition temperatures (Tg), both terminal group series were increased as Dp increased. Though Tg of hydroxyl‐terminated polymer was higher than that of phenolic‐terminated polymer in the low Dp region, both converged to the same value and the inverse number of Tg had linear correlation against the weight percentage of carbonyl groups (CO), which was calculated by Dp. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45042.