Biocidal polymers active by contact. II. biological evaluation of polyurethane coatings with pendant quaternary ammonium salts

Films of polyurethane were prepared by reaction of hydroxytelechelic polybutadienes carrying covalently bound quaternary ammonium salts with an aliphatic triisocyanate. These coatings exhibited high biocidal activity against Gram-positive and Gram-negative bacteria, yeasts, and moulds. It was found that many parameters controlled the bioactivity such as the time of contact between films and bacteria. A secondary phenomenon of diffusion only observed with the shorter alkyl chains (C8 and C10) was shown to be due to synthesis residues. After these water-soluble impurities are eliminated, the biocidal activity remains excellent; then it is due only to a contact polymer bacteria.