Influence of the N-halamine additives on the mechanical properties and fire-retardancy of biocidal plastics based on poly(vinyl chloride)

The method of biocidal plastics preparation has been described. The two types of N-halamine additives have been mixed (0.5-2 wt%) with plasticized PVC and processed by dry-blend extrusion and injection molding. The biocidal efficacy of modified PVC has been tested against two strains of bacteria: Escherichia coli and Staphylococcus aureus; and against yeast-Candida albicans. It was found that even small amount (0.5 wt%) of biocidal component yields to efficient biocidal activity of the whole plastic. The mechanical properties, hardness, abrasion, mass flow rate indicators, and flammability of obtained biocidal materials have been investigated. The examined mechanical properties of PVC were improved or remained almost unchanged after modification. For example, there has been maximum a 7% decrease in sigma(M) value for modified materials, where the average measurement error was 4%. Similarly, in the case of hardness, in comparison to initial PVC, the variations of this parameter are about 2 ShA. The values of abrasion resistance indexes were in the range from 3.07 mm(3)/m (PVC) to 4.77 mm(3)/m. However, the MFR values for obtained biocidal plastics were two times smaller. The increase of resistance to flame was observed. The LOI of PVC was 32% and for biocidal plastic even 41%.