The Study of the Mechanical Strength of Polypropylene Filter Material for the Production of Disposable Respirators

Atmospheric air, which is a natural resource, significantly affects the health and disease level of the population [1, 2], as well as the quality of the environment [3, 4]. However, as a result of anthropogenic activity, the environmental condition of the air has a tendency of constant deterioration [5, 6]. The main anthropogenic source of atmospheric pollution is large industrial conglomerates, which include motor vehicles [7, 8]. Chemical pollution of the air on a global scale leads to the greenhouse effect, the appearance of acid rain [9, 10] and pollution of aquifers [11, 12], and as a result, an increase in diseases [13], pandemics [14]. The goal of the study is to investigate the relationship between the mechanical characteristics of polypropylene filter material and their deformation under external forces for stretching and determine the safe period of use of disposable respirators. Four types of samples have been used for experimental research. Operational properties were determined by three indicators: elongation from applied force, penetration coefficient by a test aerosol of paraffin oil, and air flow resistance in accordance with the requirements of the DSTU EN 149:2017 standard. The dependence of relative elongation on tensile force has been established for samples of Eleflen and Meltblown materials with an additional layer of coarse fiber material and without an additional layer. It has been shown that the presence of an additional layer increases the tensile force of the filter material sample by 1.5 times. It has been found that the longitudinal fibers of the filter material samples withstand 15 % more external force applied for stretching, allowing manufacturers to ensure the proper fit of respirator structural elements, which ensures a longer service life. Research results show that an additional layer of material increases the strength indicators of the main filter layer by 3 times. Scientific novelty lies in determining the relationship between the mechanical characteristics of polypropylene filter material for the production of disposable protective respirators and their protective properties and deformation under external forces by stretching. The practical value involves in determining the penetration coefficient, which ensures the appropriate protective efficiency of the respirator within the range of 0 to 10 % elongation. The presence of an additional layer of coarse fiber material allows increasing this value based on the properties of the filter material (fiber thickness, packing density).