Biocidal polymers active by contact. V. Synthesis of polysiloxanes with biocidal activity

Polysiloxanes with 3-(alkyldimethylammonio)propyl pendant groups were synth esized by quaternization of n-octyldimethylamine or n-dodecyldimethyl amine with linear polysiloxanes containing 3-chloropropyl groups and/or 3-bromop ropyl groups attached to silicon atoms. The precursor polysiloxanes, poly[( 3-chloropropyl)methylsiloxane] homopolymer and various copolymers containin g (3-halogenopropyl)methylsiloxane and dimethylsiloxane units, were obtaine d by equilibrium cationic polymerization of linear and cyclic siloxanes wit h (3-halogenopropyl)methylsiloxane units. The polysiloxanes bearing quatern ary ammonium salts (QAS) showed bactericidal activity against bacteria such as Escherichia coli and Aeromonas hydrophila when incorporated in a polysi loxane network. The activity was retained after 66 days of immersion in wat er. The QAS-containing polysiloxanes are also active in aqueous solution. ( C) 2000 John Wiley & Sons, Inc.