Poly[4-pyridinyl-4´-(2-methacryloyloxyethoxy)styryl ketone-co-2-hydroxypropyl methacrylate]: Synthesis, Characterization, Thermal and Electrical properties, and Photocrosslinking behavior

Synthesis of a chalcone bearing pyridine ring, 4-pyridinyl-4´-(2-hydroxyethoxy)styryl ketone, was carried out from the reaction of 4-acetyl pyridine and 4-(2-hydroxyetoxy)benzaldehyde in an aqueous solution of NaOH. 4-Pyridinyl-4´-(2-methacryloyloxyethoxy)styryl ketone which is the methacrylate monomer bearing chalcone structure in side chain, was obtained from acylation of 4-pyridinyl-4´-(2-hydroxyethoxy)styryl ketone with methacryloyl chloride in the cold. The copolymer of 4-pyridinyl-4´-(2-methacryloyloxyethoxy)styryl ketone and 2-hydroxypropyl methacrylate was prepared by free radical polymerization in presence of AIBN at 70 oC. FTIR, 1H-NMR and 13C-APT spectroscopic techniques were used for structural characterization of the Chalcone, the monomer and the copolymer. Thermal characterization of the copolymer was carried out using DSC and TGA techniques. DSC curve shows that this copolymer has a glass transition temperature of 78 oC. The TGA curve shows that decomposition given volatile product started at 230 °C and a residue of 21% left at 500 °C. Dielectric constant (e´) of the copolymer decreased rapidly from 8.8 to 4.2 with increasing frequency in the range of 100-1000 Hz, and after this frequency e´ quantity remained constant at a value such as 4.2. e´ Value of the copolymer increased only from 4.2 to 4.9 with increasing from 290 K to 385 K. The AC conductivity of the copolymer increases from 5.01x10-10 S/cm to 126.0x10-10 S/cm as the frequency increase from 100 Hz to 5000 Hz. The AC conductivity increases slightly with increasing temperature, 2.52x10-9 S/cm at 300 K, and 2.89x10-9 S/cm at 385 K. After a solution of the copolymer was irradiated using UV light at 365 nm at room temperature, the absorption band at 356 nm disappeared and a new band was seen at 284 nm.