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Abstract
A surgical face mask is an important medical device used to protect both a surgical patient and an operating room personnel from transfer of microorganisms, body fluids and particulate material. In this research, effects of repellent finish and layering order on the fluid resistance, filtration ability and differential pressure of surgical face masks were studied. Results have demonstrated that repellent finish, fluid pressure and layering order all affect fluid resistance of surgical face masks significantly. A statistical model was developed to describe the relationship between fluid resistance and repellent finish, and fluid pressure and layering order. In determining the filtration ability of surgical face masks, techniques using Laser Scanning Confocal Microscopy (LSCM) were used to determine particle capture. Small particles present on/in nonwoven fabrics were located using LSCM. Then, image analysis was used to quantify the small particles by total area to evaluate the filtration ability. The results show that the filtration layer is the primary contributor to the barrier effectiveness of the surgical face mask. Statistical analysis was performed and the results showed that although repellent finish decreased the filtration ability of the cover layer, it did not affect the filtration ability of the filtration layer. Although layering order varied in this study, the filtration layer always stopped the penetration of the small particles. Differential pressures of face masks were also evaluated and the results showed that repellent finish did not affect the breathability of face masks while the layering order influenced the breathability significantly. Although face masks with layering order of cover fabric, filtration fabric and shell fabric provided better breathability than face masks with other layering orders, all three layering orders offered acceptable breathability. Finally, a new face mask with optimum fluid resistance, filtration ability and breathability was statistically generated according to repellent finish and layering order. This would be a face mask treated with 4.5% add-on level of Zonyl PPR protector on the cover fabric and a layering order of cover fabric, support fabric, filtration fabric and shell fabric.