This study aimed to synthesize new polymeric additives including homo- and co-polymers based on 4-methyl-2-oxo-2H-chromen-7-yl methacrylate monomer and evaluating their activity as potential antimicrobials and as pour-point depressants for modification of waxy crude oil rheology. The resultant compounds were characterized by their IR, 1H NMR and 13C NMR spectral data. The formation of the new polymers, namely, poly(7-methacryloyloxy-4-methylcoumarin) [poly(MAOMC)] homo-polymer, poly(7-methacryloyloxy-4-methylcoumarin-co-vinylacetate) [poly(MAOMC)-co-(VA)] and poly(7-methacryloyloxy-4-methylcoumarin-co- octadecyl 4-(methacryloyloxy)benzoate) [poly(MAOMC)-co-(OMAOB)] co-polymers was based on free radical polymerization. The polymerization reaction was carried at 70±2°C using 2,2'-azobisisobutyronitrile (AIBN) as an initiator and dimethylformamide (DMF)/toluene as a solvent in the case of homo-polymer [poly(MAOMC)] and co-polymer [poly(MAOMC)-co-(VA)], while polymerization proceeds at the same temperature by using benzoyl peroxide as an initiator and toluene as a solvent in the case of co-polymer [poly(MAOMC)-co-(OMAOB)]

The activities of the resultant compounds as potential antibacterial agents were evaluated against the two Gram-positive (Bacillus cereus and Staphylococcus aureus), the four Gram-negative (Escherichia coli, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Salmonella typhimrium) bacterial strains, and as antifungal agents against two fungal species (Aspergillus flavus and Candids albicans). The results showed that MAOMC monomer and poly(MAOMC)-co-(OMAOB) copolymer indicated moderate potent activity towards the bacterial and fungal strains used. At the other extreme, the influence of coumarin and octadecyl benzoate based compounds on the pour-point depression and on the rheological properties of crude oil with low asphaltene content was studied. The results indicated that all three polymers exhibited very good efficiency as additives to improve the flow-ability of the tested crude oil. Moreover, the poly(MAOMC)-co-(OMAOB) co-polymer was found to exhibit the highest performance to reduce and depress the pour-point of the tested crude oil and decrease the viscosity to a large extent due to the presence of two aromatic units with the long aliphatic carbon chain in its structure.