One-pot synthesis of cobalt-incorporated polyglycerol ester as an antimicrobial agent for polyurethane coatings

Cobalt-incorporated poly(glycerol ester) (Co-PGE) was synthesized by the polycondensation of glycerol and adipic acid followed by the reaction with cobalt(II) hydroxide under solvent-free and noncatalyzed one-pot synthesis conditions. The reaction was monitored through the acid value and hydroxyl value determination. The chemical structure and molecular weight of the poly(glycerol ester) (PGE) and Co-PGE were characterized by Fourier transform infrared spectroscopy, C-13-NMR, gel permeation chromatography, and inductively coupled plasma mass spectrometry. Co-PGE with a 59.3% degree of branching was incorporated with up to 5.0% w/w cobalt, and it exhibited antimicrobial inhibition against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in a broth microdilution study. Polyurethane (PU) coatings were prepared by the blending of 0.5-35% w/w Co-PGE containing with 5% w/w of cobalt with blank PGE, poly(ethylene glycol) with a molecular weight of 6000, poly(caprolactone diol) with a molecular weight of 2000, and additives to react with isophorone diisocyanate. The prepared PUs demonstrated mild to high antimicrobial activities against E. coli, S. aureus, Bacillus subtilis, and C. albicans strains in a disc diffusion test. PU prepared with 0.5% w/w Co-PGE showed a mild inhibition activity against S. aureus, and PU prepared with 10% w/w Co-PGE demonstrated a high inhibition activity against C. albicans. This study demonstrated that value-added Co-PGE synthesized from glycerol has the potential as an antimicrobial agent for polymer coatings in biomedical devices. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46045.