Biocides some kinetic aspects

Biological influences can be very important in the degradation of polymers, and of many other materials such as wood. It may be useful to consider biocides as a whole, regardless of the material to which they are applied, so that their role in the protection of plastics can be seen in its wider context. 

Microorganisms such as bacteria, microscopic fungi and similar species can have mechanical, chemical and biological effects. Adverse effects of these kinds are referred to as biodegradation processes. Chemical compositions which provide protection from biodegradation processes are known as biocides or, in the case of fungi, fungicides. 

The chief protecting agents are chemical substances, namely biocides, which can either be directly incorporated into the material to be protected, or applied as surface coatings. They can alternatively be added to lubricating compositions, or to the atmosphere, or to the water, or otherwise introduced indirectly into the environment. Several thousand compounds with biocidal efficacy are known. Examples include alcohols, compounds or compositions containing heavy metals, and certain surfactants. Table 1 

Name Molecular Temperature Solubility Inhibiting Penetrability Biocidic 

Besides these general demands, biocides must meet certain special requirements, associated with the material s production technology and service conditions. One illustration is that biocides designed to protect pol5nner and paint or varnish should be readily soluble in organic solvents, and should be readily miscible with other constituents of the material, or at least should form stable emulsions or suspensions. 

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London, Kluwer, 1998, p.121-34. 5 BIOCIDES SOME KINETIC ASPECTS Gumargalieva K Z Zaikov G E Russian Academy of Sciences (Institute of Materials)... 

This entry is about the preservatives used to protect plastics against attack by mildew, bacteria, fungi, algae, insects, rodents and marine fouling organisms. The preferred method for most but not all of these problems is to mix an additive with the plastics material, chosen for its antimicrobial action. The main considerations are the efficacy, environmental safety, ease of dispersion, and cost of these additives. Under the heading of efficacy we should consider not only the capacity to kill microorganisms but also the duration of that capacity. Many biocides are too transient. (There is a related entry in this book, entitled Biocides some kinetic aspects. )... 

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