Synthesis of Carboxyl Terminated Polymyrcene by Anionic Polymerization Using CO2 as a Terminating Agent

Abstract

Carboxyl terminated polymyrcene was successfully synthesized by anionic polymerization. The terminating carboxyl groups were introduced into the system using high purity CO₂ gas. Characterization of the degree of end functionalization was done by titration and gel permeation chromatography using refractive index and UV–vis detectors and a dye functionalized chain. Different reaction conditions were investigated (i.e., temperature, mode of addition of CO₂, stirring vs. not stirring) to determine their influence on the degree of functionalization. The introduction of CO₂ at −78°C through the headspace of the reactor without stirring proved to be the best reaction condition to achieve the highest amount of end functionalization of 86%–87% at a molecular weight of 20–25 kg/mol.