title: Preparation of chitosan-g-polycaprolactone copolymers through ring-opening polymerization of epsilon-caprolactone onto phthaloyl-protected chitosan.
abstract: The new biodegradable chitosan graft copolymer, chitosan-g-polycaprolactone, was synthesized by the ring-opening graft copolymerization of epsilon-caprolactone onto phthaloyl-protected chitosan (PHCS) at the hydroxyl group in the presence of tin(II) 2-ethylhexanoate catalyst via a protection-graft-deprotection procedure. Toluene acted as a swelling agent in this heterogeneous system. The grafting reactions were conducted with various PHCS/monomer/toluene feed ratios to obtain chitosan-g-polycaprolactone copolymers with various polycaprolactone contents. The chemical structure of the chitosan-g-polycaprolactone was characterized by Fourier transform infrared and one- and two-dimensional NMR spectroscopy. After deprotection, the phthaloyl group was removed and the amino group was regenerated. Thus the obtained chitosan-g-polycaprolactone was an amphoteric hybrid with a large amount of free amino groups and hydrophobic polycaprolactone side chains. Some properties of the final product were also investigated, such as crystallinity, thermal property, and solubility.
authors.affiliation: Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Yusong
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Shen
authors.forename: Yue'e
authors.initials: Y
authors.lastname: Fang
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D002208:Caproates / Q000737:chemistry*; D002686:Chitin / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011108:Polymers / Q000138:chemical synthesis*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000596:Amino Acids; D001672:Biocompatible Materials; D002208:Caproates; D007783:Lactones; D011108:Polymers; D002686:Chitin; C121056:caprolactone; D048271:Chitosan