Abstract:

Legal regulations concerning protecting workers threatened with biological factors in the workplace and the global threat of terrorist attacks influence the need to master the properties of protective equipment and the methods of its evaluation. The article presents an approach to nonwovens with biocidal properties designed for respiratory protection devices (RPD) against bioaerosols. It was assumed that these materials should fulfil two basic criteria – high efficiency of filtration against bioaerosols and have the ability to destroy microorganisms blocked in the nonwoven. An experimental setup that enabled to control the flow of bioaerosol by a sample of nonwovens was created, making it possible to also evaluate the efficiency of filtration by applying a particle counter. Microorganisms with an aerodynamic diameter of ≤ 1.0 µm and various shape were selected for the study, all belonging to two aerobic types of gram positive (+) and gram negative (-) bacteria. The measurement was based on bioaerosol flow through a filter with a diameter of 80 mm, at a volumetric flow rate of 30 l/min, for 15 minutes. Tightly sealed filters were stored for 2, 4 and 8 hours at a temperature of 37 °C. In order to evaluate bacteria survival after contact with the bioactive nonwoven, they were rinsed and shaken for 15 minutes in a shaker at a frequency of rotation of 150 c.p.m. After dilution in sterile saline, microorganisms were seeded on a sterile Petrie’s dish. They were later incubated at a temperature of 37 °C for 24 hours, after which time the colonies grown were counted. Applying the method discussed, the efficiency of filtration against aerosol was confirmed as well as the bioactivity of meltblown nonwovens made from poly (lactic acid PLA) modified with a biocidal compound.