The chlorosulfonated polyethylene (CSM)s with different content of chlorine and sulfur elements were prepared by aqueous solution suspension method. Prepared CSMs were characterized by Fourier transform infrared (FTIR) spectra. The content of chlorine and Sulfur elements of CSM was confirmed by ion chromatography. The thermal properties and crystallization behaviors of the prepared CSMs were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. In each TGA curve, one can observed two distinct weight loss steps, and the degradation temperatures decreased with the content of chlorine and sulfur elements increasing. The degradation temperatures of all the prepared CSMs exceeded 170 degrees C in air, which showed good thermal stability. The calculated Avrami exponent by the (sic) nonisothermal crystallization kinetics equation was nearly 4, which proved the CSM was homogeneous nucleation with a three-directional spherulitic growth. The WAXD results indicated that the crystallinity of CSM decreased with the increment of chlorine and sulfur content. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116:2095-2100, 2010