Examining the effect of nanosilver on the antibacterial fire-retardant coatings for pharmaceutical enterprises

Abstract

We examined the effect of nanosilver - ionic silver, intercalated into interlaminar spaces of montmorillonite, as a biocidal additive to antibacterial fire-protection coatings for pharmaceutical enterprises. We determined stability of intumescent coatings composed of ammonium polyphosphate/pentaerythritol/melamine/EVA/titanium oxide with additives of montmorillonite, modified with guanidine and quaternary ammonium cations as well as ions of silver in relation to mold and wood-staining fungi. It was shown that the application of a mixture of biocides - montmorillonites, modified with ions of silver and polyhexamethyleneguanidine cation, improves the class of biocidal effectiveness of coating from "not effective" to "effective. It was established that the mixture of Ag-montmorillonite and PHMG-montmorillonite demonstrated the synergistic effect against mold and wood-staining fungi and provided the "highly effective" class of biocidal effectiveness. According to data of microbiological studies, the paint, which contains in its composition the mixture of Ag and PGMG cations, exerts a disinfectant effect in relation to gram-positive and gram-negative bacteria (including tuberculosis), as well as mold fungi. Field fire studies of intumescent paints for wood with the additives of Na-MMT, TSTA-MMT, PHMG-MMT and Ag-MMT were conducted in line with GOST 16363. It was shown that the admixtures of nanoclays into water-based intumescent paints decrease the temperature of flue gases and transfer wood into group I of fireretardant effectiveness. Results of the study allow us to recommend the introduction of the mixture (PHMG-MMT+Ag-MMT) into formulations of intumescent paints as an effective antibacterial additive. Its properties are predetermined by the suppression of proliferation of grampositive and gram-negative bacteria, mold and wood-staining fungi.