Polymeric biocides

Journal of Applied Polymer Science 93, No.2, 15th July 2004, p.765-70 SYNTHESIS AND PROPERTIES OF POLYMERIC BIOCIDES BASED ON POLY(ETHYLENE-CO-VINYL ALCOHOL)... 

No.18,15th Sept.2001, p.3073-84 NOVEL REFRESHABLE N-HALAMINE POLYMERIC BIOCIDES CONTAINING IMIDAZOLIDIN -ONE DERIVATIVES... 

POLYMERIC BIOCIDES. PENTACHLOROPHENOL-FUNCTIONALISED VARNISH RESINS... 

Another polymeric biocide (4.10) has been found to adhere to cotton to give a durable antiodor finish to socks and towels.83 Poly(hexamethylenebiguanide hydro-choride) is already used in swimming pools and in personal care products. 

Antimicrobial polymers have been classified in three different major groups. There are biocide-releasing polymers, polymeric biocides, and biocidal polymers (Figure 15.2). 

In general, biocide-releasing polymers have no influence over their intrinsic antimicrobial activity. The polymers are simply acting as carriers for biocides or antibiotics. The biocidal molecules, which are incorporated in the polymer matrix and/or tethered to the polymer backbone, are released. One of the major advantages of these systems is that the release of the embedded antimicrobial active substances is controlled by the used polymeric system. Therefore, the rates of release are adjustable and polymers can release the biocides very close to the cell, which makes them efficient. However, the polymers still release biocides into the environment and will eventually become inactive. Polymeric biocides contain biocidal repeating units. Such macromolecules often show the same mode of action as their repeating units with somewhat lower activity, due to the steric hindrance caused by the polymeric backbone. Biocidal polymers distinguish themselves by the fact that they act as a whole molecule. Further, biocidal polymers have been found to show a lower tendency to build up bacterial resistance. ... 

Figure 15.2 General working principles of antimicrobial polymers (a) biocidereleasing polymers, (b) polymeric biocides, and (c) biocidal polymers.

Polymeric biocides are formally composed of repeating units that contain biocidal groups. This is achieved by either polymerizing monomers with biocidal motives or derivatizing polymers with such motives by polymer-analogous reactions. Figure 15.3 depicts a selection of biocidal monomers. 

In conclusion, the activity of polymeric biocides depends strongly on the nature of the respective biocides and the binding strategy. In some cases, the polymers are even more active than their respective monomers. 

Heterocyclic compounds are used in coatings rather than moulded plastics. There are water-insoluble polymeric biocides, such as the polystyrene hydantoins (see Structure III). Some of these latter substances can be rendered inactive by reducing agents or even by excessive doses of bacteria, but it is claimed that they can be reactivated by sodium hypochlorite. 

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