The investigation of grafting kinetics of a new macroinitator with various monomers by atom transfer radical polymerization method

In this study, the 3,5-di(chloro asetato) phenol was synthesized by the esterification reaction of chloroacetyl chloride with 1,3,5-trihydroxy benzene (1:2 by mole) between 0-5oC and in presence of triethylamine. A two-armed new methacrylate monomer having ? -chlorine carbonyl group, 3,5-di(chloroasetato) phenyl methacrylate (DCPMA), was synthesized by reaction of 3,5-di(chloro asetato) phenol with methacryloyl chloride. After the synthesized monomer had been characterized by 1H-NMR, MS and FT-IR techniques, its a copolymer with methyl methacrylate, poly(DCPMA:0.01-co-MMA:0.99), containing amount of 1 mol-% having ? -halo. carbonyl group in the side groups was prepared by free radical polymerization method. The two-armed graft copolymers of ethyl methacrylate (EMA), methyl methacrylate (MMA), n-butyl methacrylate (n-ButMA) and isobornyl methacrylate (IBMA) were prepared via atom transfer radical polymerization method catalyzed by CuCl/2,2?-bipyridine (Cu/bpy) catalyst system when this copolymer was used as a macroinitiator. The AB type block copolymers of ethyl methacrylate and styrene were also tested to understand of controlled growing up of side groups in the graft copolymerization.The 1H-NMR, 13C-NMR and FT-IR techniques were used in the characterization of graft copolymers. The average molecular weights and polydispersities of two-armed graft copolymers were confirmed by GPC technique. Two-armed grafting kinetics of n-ButMA was investigated in detail. While the number-average molecular weights of a graft copolymer series of n-ButMA ended at different times were increasing from 55.700 to 99.500, the polydispersities decreased from 1.85 to 1.39 by depending on time. These results show that two armed grafting kinetics of n-ButMA adjust to controlled polymerization kinetics. The solubility parameters of polymers were calculated according to literature. The glass transition temperatures of prepared graft copolymers were measured from DSC curves. While the graft copolymer of IBMA showed two glass transition temperatures at 126 and 205oC, the blend copolymer prepared by PIBMA homopolymer and macroinitiator were mixed at the equal ratios, showed one transition at 132oC. The thermal decomposition temperatures of copolymers were investigated by TGA. The thermal degradation of macroinitiator was also investigated. The activation energies of thermal decomposition of graft copolymers were determined by Flynn-Wall-Ozawa method profit from decomposition curves at different heating rates. The change of dielectric behavior as function of frequency for macroinitiator samples at pure and CuBr dopant at different ratios were investigated in detail.Key words: Atom transfer radical polymerization, two armed graft copolymer, alkyl methacrylate, glass transition temperature, thermo gravimetric analysis, dielectric properties.