Synthesis of copolymers containing photosensitive and biodecomposible side group, and investigation of photochemical and dielectric properties

In this work, firstly 3-hydroxybenzaldehyde, 4- (2-hydroxyethoxy) benzaldehyde was reacted with 4-Acetyl pyridine to synthesize two different chalcones. These chalcones containing hydroxyl side groups were acylated with methacryloyl chloride to synthesize hydroxyl side-chain methacrylate monomers. The synthesized monomers were copolymerized with 2-hydroxypropyl methacrylate by free radical polymerization technique. These two types of copolymers synthesized were grafted by ring opening polymerization with 3,6-dimethyl-1,4-dioxane-2,5-dione (lactide). FT-IR, 1H and 13C-APT techniques were used in the characterization of the synthesized chalcones, monomers and copolymers. Thermal behaviors of copolymers were studied by DSC and TGA. The changes in the photochemical behavior of the synthesized copolymers and the dielectric properties of the polymers were investigated. The copolymer of 2-hydroxypropyl methacrylate with methacrylate monomer of chalcone synthesized from 3-Hydroxybenzaldehyde and acetyl pyridine showed absorption around λmax = 250 nm and a new band at around 290 nm was formed by UV irradiation. This copolymer showed a Tg temperature of around 82 °C. The dielectric constant was decreased fast up to 700 °C, very slow between 700-1260 Hz and remained constant between 1260-5000 Hz at room temperature. Ac conductivity increased with temperature and increased faster around 80 oC. The thermal stability of the polylactide-bonded polymer decreased and fragmentation accelerated. The copolymer of 2-hydroxypropyl methacrylate with methacrylate monomer of chalcone synthesized from 4-(2-hydroxyethoxy) benzaldehyde and acetyl pyridine showed absorption around λmax = 255 nm and λmax = 354 nm. A new band at 280 nm was formed when the absorbance of these bands was reduced by UV irradiation. This copolymer showed a Tg temperature of around 78 °C. The dielectric constant was decreased fast up to 700 °C at room temperature. Ac conductivity increased with temperature. The thermal stability of the polylactide-bonded polymer decreased and fragmentation accelerated.