Graft copolymers of chitosan with acrylonitrile (AN) were prepared by free radical polymerization using initiator pair of ammonium persulfate and sodium thiosulfate as redox system firstly. Graft copolymerization was confirmed by FTIR spectra, X-ray diffraction and H-1 NMR spectra measurements The. mechanism of graft copolymerization and factors affected graft reaction were explored in details, and the optimum reaction conditions were obtained at [AN] 0.9 mol/L, [CS] 13.3 g/L, [Initiator] 0.006 mol/L, 62 +/- 1 degrees C and 2 h. Then the solubility of chitosan-g-PAN was investigated by using several solvents. The concentrated nitric acid solution and NaSCN solution are good solvents for the graft product. It's confirmed that composites of graft copolymer and PAN had a good film-forming property, and it is suggested that the graft copolymer is promising for fabrication of acrylic fibers as a kind of functional additive. (C) 2009 Elsevier Ltd. All rights reserved