Sodium and potassium butyl xanthates (Nabxt and Kbxt) were prepared in the laboratory. Characterization of these xanthates were done using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance ((1)H NMR) spectroscopy, thermogravimetric analysis (TGA), and differential thermal analysis (DTA) techniques. These xanthates were used as accelerators for the prevulcanization of natural rubber latex (NRL) at room temperature. Optimization of prevulcanization time was done. Films were casted from these prevulcanized NRL. Tensile properties of latex vulcanisates were measured and potassium butyl xanthate gave superior properties to the NRL films compared with sodium butyl xanthate. Effect of thermal ageing on tensile properties of these prevulcanized NRL films was also investigated and these properties were found to be improved after thermal ageing. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 1325-1332, 2011