Potential application of some coumarin derivatives incorporated thiazole ring as ecofriendly antimicrobial, flame retardant and corrosion inhibitor additives for polyurethane coating

Coumarin derivatives continue to draw the attention of synthetic organic chemists due to their versatile utility associated with them and their widely use as pharmaceuticals. Coumarin derivatives having various substituted thiazole rings at carbon-3 exhibit promising biological activities. In this research, two series of coumarin derivatives incorporated thiazole ring were prepared; coumarin thiazole derivative and benzo coumarin thiazole derivative, the structures of the products were confirmed by elemental analysis, FTIR, 1HNMR and mass spectroscopy. The prepared coumarin derivatives I-III was incorporated physically into polyurethane coating as an additive. Experimental coatings were fabricated on a laboratory scale and applied by brush on steel and wood panels. The coated films were screened against gram-negative bacteria, gram-positive bacteria and fungi to evaluate the antimicrobial activity of the prepared coumarin derivatives. A flame retardant property, the corrosion resistance and the mechanical properties of these coated films were also examined to evaluate the drawbacks of the prepared coumarin derivatives as an additive. The obtained results showed that, the incorporation of a few amount of the prepared coumarin derivatives into polyurethane coating have led to improve the antimicrobial activity, flame retadancy, corrosion resistance, gloss and scratch hardness of the polyurethane coated films.