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, Me_3?n Al(O(CH₂)₄OCH?CH₂)_n (n = 1 ( 1 ), 2 ( 2 ), 3 ( 3 )), are synthesized and investigated by multinuclear (¹H, ¹³C, ²⁷Al) 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 _n up to 35 000 g mol^?1) and relatively narrow molecular weight distribution (M _w/M _n < 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.