A methacrylate monomer, cyclohexene-3-yl methyl methacrylate (CHMA) was synthesized by reaction of 3-cyclohexene-1-methanol with methacryloyl chloride in the presence of triethylamine at 0-5 degrees C. The homopolymer of CHMA and its copolymer with styrene (St) were prepared by free radical polymerization. The Fourier transform infrared (FT-IR), H-1 NMR, and C-13 NMR spectroscopic techniques were used to characterize the homopolymers and copolymers. H-1 NMR spectra were used to determine the compositions of the copolymers. Linearization methods such as Kelen-Tudos, Extended Kelen-Tudos, and a non-linear least squares method were all used to determine the reactivity ratios of the monomers. The effect of copolymer compositions on their thermal behavior was studied by differential thermal analysis and thermogravimetric analysis methods.