3.5. Wide-angle X-ray diffraction
The variation in the crystal structure upon graft copolymerization was studied using WAXD, and the corresponding patterns were illustrated in Fig. 4. Two typical peaks at ca 11◦and 20◦were found in the pattern of CS, whose crystal form has been reported to berhombic [24]. While the crystalline peak around 11◦was attributed to the hydrated crystalline structure of chitosan, the peak around 20◦was ascribed to the relatively regular crystal lattice of chitosan [25]. After the grafting reaction, the intensity of these two 5