Multilayer and Multiscale Structures for Personal Protective Equipment

The COVID-19 pandemic has revealed the numerous limitations of personal protective equipment (PPE) such as face masks and has shown an urgent need for the adaptation of standardization criteria to ensure systematic use [...]

Antibacterial and Biodegradable Electrospun Filtering Membranes for Facemasks: An Attempt to Reduce Disposable Masks Use

Due to the prevalence of the COVID-19 pandemic, the demand for disposable facemasks has become a global issue. Unfortunately, the use of these products has negative effects on the environment, and therefore, the use of biodegradable materials is a powerful strategy to overcome this challenge. Aligned with this concept, in this work, biodegradable facemasks were developed using poly(ε-caprolactone) (PCL) polymer and cotton natural fibers. The filter layer was produced using an electrospinning technique, since electrospun membranes present remarkable characteristics for air filtration. The electrospun membranes were functionalized with different nanoparticles (NPs), including silver (Ag), titanium dioxide (TiO2) and magnesium oxide (MgO), in order to include new properties, namely antibacterial effect. The developed membranes were characterized by FESEM, EDS, ATR-FTIR, GSDR and TGA, which confirmed the successful impregnation of NPs onto PCL membranes. The antibacterial effect and filtration efficiency were assessed, with the PCL/MgO NPs membrane presenting better results, showing inhibition zone diameters of 25.3 and 13.5 mm against Gram-positive and Gram-negative bacteria, respectively, and filtration efficiency of 99.4%. Three facemask prototypes were developed, and their filtration efficiency, air permeability and thermal comfort were evaluated. Overall, this study demonstrates the potential of PCL/NPs electrospun membranes to act as an active and biodegradable filter layer in facemasks.

Protective Multifunctional Fibrous Systems Based on Natural Fibers and Metal Oxide Nanoparticles.

In recent years, an unprecedented increase in the development of products and technologies to protect the human being has been observed. Now, more than ever, the world population is exposed to several threats, harmful to their well-being and health. Chemical and biological hazardous agents stand out as one of the biggest threats, not only for the military forces, but also for the civilians. Consequently, it's essential to develop personal protective systems that are able to protect their user, not only passively, but actively, being able to detect, adsorb, degrade and decontaminate pesticides, pollutants, microorganisms and most importantly: chemical/biological warfare agents. One recent strategy for the development of active fibrous structures with improved functions and new properties is their functionalization with nanoparticles (NPs), especially metal oxides. Although their known effectiveness in the decomposition of harmful agents, the NPs could also include other functionalities in the same structure using low quantities of material, without adding extra weight, which is of huge importance for a soldier in the battlefield. The use of natural fibers as the substrate is also very interesting, since this material is a much sustainable alternative when compared to synthetic ones, also providing excellent properties.