Copolymer synthesis of coumarin based acrylate monomer and its thermal and dielectric measurements

In this study, firstly, 2-oxo-2H- chromic-7-yl acrylate monomer was synthesized by reaction of 7-hydroxy coumarine and akryloilchloride in presence of triethylamine at 0-5 oC. After the synthesized monomer had been characterized with 1H-NMR and FT-IR techniques, some copolymers were synthesized by methyl methacrylate, ethyl methacrylate, isobutyl methacrylate and chloromethyl styrene by using free radical polymerization. The macroinitiator, p(St-co-KMS 0,07), was synthesized from styrene and chlorometyl styrene by using free radical polymerization method. The graft copolymer of 2-oxo-2H- chromic-7-yl acrylate was synthesized by ATRP method at 90 oC in presence of CuBr/bpy as catalyst. The structures of macroinitiator and copolyme prepared were characterized by 1H-NMR and FT-IR techniques.Polidispersities and average-molecular weights of copolymers were measured by GPC technique. The UV and flourimetry measurements of some copolymers were carried out. The intrinsinc viscosity coefficients of some copolymers were determined by Ostwald viscozimetry. The glass transition temperatures (Tg) of copolymers were determined from Differential Scanning Calorimetry (DSC) curves.Thermal stabilities of copolymers prepared with methyl methacrylate, ethyl methacrylate, isobutyl methacrylate of 2-oxo-2H-chromic-7-yl acrylate were determined by the TGA curves. The thermal decomposition activation energy of copolymers were calculated according to the method Flynn-Wall-Ozawa by using decomposition curves at different heating rates. Dielectric constants of copolymer were measured at 100 Hz and room temperature. The dielectric behavior of the copolymers versus frequency were investigated at room temperature. In addition, the dielectric behavior of polymers versus temperature were also examined.