Preparation and characterization of poly(ε-caprolactone)-b-polyacrylonitrile (PCL-b-PAN) and poly(L-lactide)-b-polyacrylonitrile (PLLA-b-PAN) copolymers by aluminum and lithium alkoxides containing double-headed initiators

Three new metal alkoxides, [(MMPEP)Al(mu-OCH2C6H4CH2Cl)](2) (1), [(MMPEP-H)Li center dot (BnOH)](2) (2) and [(MMPEP-H)Li center dot (HOCH2C6H4CH2Cl](2) (3) (MMPEP-H-2: 2,2-methylene-bis {4,6-di(1-methyl-1-phenylethyl)phenol}) have been synthesized and characterized. Complex 1 was prepared by the reaction of [(MMPEP)Al(CH3)(Et2O)] with p-(chloromethyl)benzyl alcohol. Followed by the reaction of MMPEP-H-2 with "BuLi, BnOH or p-(chloromethyl)benzyl alcohol was added to give complexes 2 and 3, respectively. Complex 1 has shown excellent catalytic activity towards ring-opening polymerization (ROP) of F-caprolactone. Both complexes 2 and 3 are active for ROP Of L-lacticle. Block copolymers of poly(epsilon-caprolactone)-b-polyacrylonitrile (PCL-b-PAN) and poly(L-lactide)-b-polyacrylonitrile can be synthesized by combining a technique of atom transfer radical polymerization (ATRP) and ROP using a double-headed initiator. Microphase-separated morphology of PCL-b-PAN has been observed by transmission electron microscopy, indicating the formation of self-assembled nanostructure. (c) 2007 Elsevier Ltd. All rights reserved.