Synthesis of Functional Poly(ε-caprolactone)s via Living Ring-Opening Polymerization of ε-Caprolactone Using Functionalized Aluminum Alkoxides as Initiators

The new aluminum compounds 1–3 modified by unsaturated alcohol, MeAl(O(CH)OCHCH) (n = 1 (1), 2 (2), 3 (3)), are synthesized and investigated by multinuclear (H, C, Al) NMR spectroscopy. The compounds 1–3 initiate living ring-opening polymerization of ε-caprolactone in bulk at 40–80 °C to afford polyesters with controlled molecular weight (M up to 35 000 g mol) and relatively narrow molecular weight distribution (M/M < 1.8). Among initiators studied here, aluminum trialkoxide shows the highest activity, whereas aluminum dialkoxide is a less active. In all cases, the fragment of unsaturated alcohol is transferred to the end of the polymeric chain with high degree of functionality (>85%) yielding macromonomers. These macromonomers are copolymerized with maleic anhydride to give poly(vinyl ether-co-maleic anhydride)-g-poly(ε-caprolactone) graft copolymers. (Figure presented.).