Synthesis and Characterization of Polyethyleneimine-graft-Poly ( p-dioxanone ) Copolymers

To decrease the toxicity of polyethyleneimine ( PEI ) and broaden the application of PEI in biomedical materials, amphiphilic graft copolymers of polyethyleneimine-graft-poly ( p-dioxanone ) ( PEI-g-PPDO ) have been synthesized via a "graft from" strategy using PEI as macro-initiator and stannous octoate ( Sn( Oct )(2) ) as catalyst. The molecular structure of the copolymer was characterized by FTIR, H-1-NMR and H-1-C-13-HMQC. The results suggested that the molecular structure of the copolymer could be effectively adjusted by monomer content in reagent. DSC was performed for investigating the thermal and crystalline properties of the copolymer. The crystallization behaviors of the copolymer directly depend on the graft chain length and the PPDO content. The micellization behaviors of the copolymer in water was also studied by using pyrene as probe, and showed that the copolymer could form stable micelle in water.