Polymerization of lactides and lactones, 8: Study on the ring-opening polymerization of 3-phenyl-ε-caprolactone and 5-phenyl-ε-caprolactone

Abstract

Ring-opening polymerization of 3-phenyl-εcaprolactone (3-ph-CL) and 5-phenyl-ε-caprolactone (5-ph-CL) by tin(II) salt, Al(OiPr)3 and CpNa has been studied; 3-ph-CL cannot be initiated by Al(OiPr)3. Polymerization of 5-ph-CL initiated with Al(OiPr)3 in toluene at 15°C yielded a polymer of a predictable molecular weight and a narrow molecular weight distribution. 3-ph-CL and 5-ph-CL can be polymerized by initiating with tin(II) salt, and CpNa. In CpNa-based polymerization, high molecular weight P(3-ph-CL) and P(5-ph-CL) were obtained. DSC studies indicate that P(5-ph-CL) is an amorphous material, exhibiting a rubber state at room temperature. Compared with PCL. the glass transition temperature of P(3-ph-CL) and P(5-ph-CL) is higher (-60°C), in contrast to the melting temperature, which is higher for PCL. These new monomers give a route to novel aliphatic polyesters.