Chlorinated polymers, microbial

Being able to tolerate up to 1 ppm free chlorine on continuous basis offers some protection from biological growth on the membrane. This is particularly important because the CA polymer itself supplies nutrients for microbial populations, which then metabolize the polymer and degrade the membrane. 

The increasing occurrence of microbial and nosocomial infection has stimulated research activities into antimicrobial polymers and textiles [19, 25, 34]. Most medical textiles and polymeric materials used in hospitals are conductive to crosstransmission of diseases, as most microorganisms can survive on these materials for hours to several months [17, 26]. Thus, it would be advantageous for polymeric surfaces and textile materials to exhibit antibacterial properties so as to reduce and prevent disease transmission and cross-contamination within and from hospitals. N-halamines exhibit a similar antimicrobial potency to chlorine bleach, one of the most widely used disinfectants, but they are much more stable, less corrosive and have a considerably reduced tendency to generate halogenated hydrocarbons, making them attractive candidates for the production of antimicrobial polymeric materials. N-halamine compounds are currently used as antimicrobial additives to produce polymers with antimicrobial and biofilm-limiting activities. 

Solvent Extraction of PHAs. The majority of the patented separation processes describe the extraction of PHB from microbial biomass using organic solvents such as chlorinated hydrocarbons (eg chloroform or 1,2-dichloroethane), azeotropic mixtures [eg 1,1,2-trichloroethane with water (65)] chloroform with methanol, ethanol, acetone, or hexane (66), and cyclic carbonates [eg hot (120-150°C) ethylene carbonate or 1,2-propylene carbonate (67)] in which the polymer is soluble. With the wider variety of PHAs which can be produced today, the choice of solvents should be carefully considered. In general, solvents which are suitable for PHB should be equally good for any SCL and MCL PHA. The reverse may not be true. For example, while semicrystalline PHB is insoluble in acetone, MCL PHA will dissolve in it. 

The polymers were able to transfer this chlorine atom directly to microbial cells. The chlorine oxidized the phospholipids of the cell membrane, which resulted in the death of the microbial cells. Schoenfisch and coworkers prepared polymers with functional diazeniumdiolate groups, which were able to release NO within several hours. 

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