Nvinylimidazole (VIM), and phenacyl methacrylate (PAMA) copolymerized with different feed ratios using 1,4dioxane as a solvent and , 'azobisisobutyronitrile (AIBN) as an initiator at 60°C. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis (content of N for VIMunits) and by Fourier transform infrared spectroscopy through recorded analytical absorption bands for VIM (670 cm -1 for CN of imidazole ring) and PAMA (1730 cm -1 for CO of ester group) units, respectively. Monomer reactivity ratios for VIM (M 1 )PAMA (M 2 ) pair were determined by the application of conventional linearization methods such as FinemanRoss (FR) and KelenTüdös (KT) and a nonlinear error invariable model method using a computer program RREVM. The molecular weights ( w and n ) and polydispersity indices of the polymers were determined using gel permeation chromatography (GPC). Thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Also, the apparent thermal decomposition activation energies (ΔE d ) were calculated by Ozawa method using the SETARAM Labsys TGA thermobalance. The antibacterial and antifungal effects of polymers were also tested on various bacteria, fungi and yeast.