Stereogradient polycaprolactones formed by asymmetric kinetic resolution polymerization of 6-methyl-ε-caprolactone

Chiral phosphoric acid (CPA) catalyzed asymmetric kinetic resolution polymerization (AKRP) of 6-methyl-ε-caprolactone (6-MeCL) has been developed to synthesize stereogradient polycaprolactones. When using ( R )-CPA as the catalyst, ( R )-6-MeCL monomers were preferentially consumed, which was determined by chiral H plc analysis and kinetic experiments. The AKRP process delivered polycaprolactones (PCLs) with high chain-end fidelity, controlled molecular weights and narrow molar mass dispersity. Moreover, the thermal properties, viscoelasticity and degradation characteristics of the resulting PCLs were also investigated.