Kinetics study of graft polystyrene onto natural rubber (PS-g-NR) prepared by emulsion polymerization was predicted for the first time from transmission electron microscope (TEM) micrographs and thermal gravimetric analysis (TGA) diagrams. The copolymer growth or rate of grafting was followed from beginning to the end of polymerization reaction. Two models of shell percentage were formulated from TEM images using Image J software to estimate the size of shell. It was found that two models can be used to predict the shell percentage or grafted polystyrene. Finally, another model was formulated from TGA results which represented a %weight loss at 400 degrees C with grafting percentage. These models can quickly predict the reaction rate and estimate the kinetics behavior of the reaction. (C) 2015 Elsevier Ltd. All rights reserved.