Homogeneous synthesis and characterization of graft copolymer of chitosan/polycaprolactone

The homogeneous graft copolymerization of e-caprolactone(e-CL)onto chitosan(CS)in ionic liquid 1-butyl-3-methylimidazolium acetate(Ac)was studied.The effect of various reaction parameters on grafting percentage was evaluated and the obtained graft copolymer was characterized by FTIR,1H NMR,TGA and XRD.The results showed that graft copolymerization occurred with high reaction efficiency under the homogeneous conditions,and the grafting percentage of 250% was achieved at temperature 105℃,time 8 h,catalyst concentration 0.1%(mass) of e-CL and molar ratio e-CL to CS 20.The thermal stability of graft copolymer decreased as compared with CS,because of a variety of crystal structures of CS occurring with the grafting of e-CL onto CS.