Kinetic Study of the Al‐Schiff's Base Initiated Polymerization of ε‐caprolactone and Synthesis of Graft Poly(methylmethacrylate‐g‐caprolactone)

Graft copolymers of polycaprolactone (PCL) on polymethacrylate (PMMA) backbone have been successfully synthesized and characterized by SEC, 1H and 13C NMR spectroscopy. The strategy used consisted of polymerizing ε‐CL, followed by end‐functionalization of the resulting PCL using methacryloyl chloride. Free radical polymerization of the methacryl double bond lead to the C‐C polymer backbone and an overall graft copolymer. The polymerization of ε‐caprolactone was achieved using Al‐Schiff's base isopropoxide (HAPENAlOiPr) in DCM at ambient temperature. SEC and MALDI analysis of the polymers confirmed that mostly linear chains were obtained with the Al initiator, up until high monomer conversion. The low molar mass PCL was then end‐capped with a methacryloyl group, in a quantitative manner, as evidenced by 1H NMR. The macromonomer thus obtained was copolymerized in small proportions with methyl methacrylate by conventional free radical polymerization and atom transfer radical polymerization (ATRP). Analysis of the products by NMR and SEC showed the presence of true graft copolymers and the absence of homopolymers.