Synthesis of novel isocoumarin derived copolymers and investigation of thermal properties

In present study, a copolymer series of an isocoumarin derived monomer 2-(isocoumarin-3-yl)-2-oxo-ethyl methacrylate (IKEMA) with methyl methacrylate (MMA) at different compositions was prepared by free radical polymerization method. At the spectral characterization of copolymer systems, FTIR and 1H-NMR techniques were used. Thermal properties of isocoumarin derived copolymers at different compositions were determined by thermogravimetric analysis method (TGA). Thermal degradation kinetics of poly (IKEMA:0,48-co-MMA) copolymer system containing 48% isocoumarin unit (IKEMA) was investigated in detail. For this purpose, different kinetic methods such as Flynn-Wall-Ozawa, Kissinger, Coats-Redfern, Tang, Madhusudanan, Van Krevelen and Horowith-Metzger method were used. Thermal decomposition activation energy of the reference copolymer was calculated as 126.17 kJ/mol and 125.32 kJ/mol according to Flynn-Wall-Ozawa and Kissinger methods. The best fit with these two methods was achieved using the Coats-Redfern method (E=128.43 kJ/mol, R=0.9986). Accordingly, it was determined that the thermal decomposition mechanism of a novel copolymer containing isocoumarin ring poly(İKEMA:0,48-co-MMA) proceeded through a D1 one-dimensional diffusion type deceleration mechanism over the optimum heating rate of 5 °C/min.