Preparation and characterization of chalcone functional urethane acrylates for coating applications

New chalcone modified urethane acrylates (CMUA) were synthesized by the reaction of photoactive 4,4'dihydroxychalcone and polyethylene glycol 1000 (PEG-1000) with isophorone diisocyanate (IPDI) and followed by end-capping with 2-hydroxyethyl methacrylate (HEMA). The structure of CMUA oligomers was characterized by FT-IR and H-1 NMR spectroscopies. Photosensitivity of CMUA oligomers was confirmed by using UV-vis absorption spectroscopy. The UV-curable clear coatings were prepared by the incorporation of CMUA oligomers into formulations together with reactive diluents such as dipropylene glycol diacrylate (DPGDA), 1,6-hexanediol diacrylate (HDDA) and photoinitiator and applied on Plexiglas plates and Teflon moulds. The physicochemical, mechanical and thermal properties of UV-cured coatings such as gel content, gloss, chemical solvent resistance, contact angle, gloss, pendulum hardness, pencil hardness, tensile properties and char yield were investigated. The effect of chalcone modification on UV-cured CMUA coatings was evaluated and determined as the improvement in the properties of UV-cured coatings mainly due to the photocrosslinking ability of 4,4'dihydroxychalcone.