Characterization and Filtration Efficiency of Sustainable PLA Fibers Obtained via a Hybrid 3D-Printed/Electrospinning Technique

Electrospun nanofibers for medical face mask with protection capabilities against viruses: State of the art and perspective for industrial scale-up

Face masks have proven to be a useful protection from airborne viruses and bacteria, especially in the recent years pandemic outbreak when they effectively lowered the risk of infection from Coronavirus disease (COVID-19) or Omicron variants, being recognized as one of the main protective measures adopted by the World Health Organization (WHO). The need for improving the filtering efficiency performance to prevent penetration of fine particulate matter (PM), which can be potential bacteria or virus carriers, has led the research into developing new methods and techniques for face mask fabrication. In this perspective, Electrospinning has shown to be the most efficient technique to get either synthetic or natural polymers-based fibers with size down to the nanoscale providing remarkable performance in terms of both particle filtration and breathability. The aim of this Review is to give further insight into the implementation of electrospun nanofibers for the realization of the next generation of face masks, with functionalized membranes via addiction of active material to the polymer solutions that can give optimal features about antibacterial, antiviral, self-sterilization, and electrical energy storage capabilities. Furthermore, the recent advances regarding the use of renewable materials and green solvent strategies to improve the sustainability of electrospun membranes and to fabricate eco-friendly filters are here discussed, especially in view of the large-scale nanofiber production where traditional membrane manufacturing may result in a high environmental and health risk.

Non-Woven Filters Made of PLA via Solution Blowing Process for Effective Aerosol Nanoparticles Filtration

With the development of civilization, the awareness of the impact of versatile aerosol particles on both human health and the environment is growing. New materials are needed to purify the air to control this impact The aspect of processing the produced waste is not negligible. In view of the above, this study proposes utilizing the solution blow spinning process (SBS) for manufacturing a biodegradable filtration structure that ensures high efficiency of nanoobject filtration, with a low pressure drop. Polylactic acid (PLA) was used to produce a nanofiber layer on the coconut substrate. The advantage of this method is the ability to blow fibers with diameters in the nano-scale, applying relatively simple, cost-effective, and easy to scale-up equipment. This work selected appropriate process parameters to produce good quality filters. Moreover, the process conditions influence on the morphology of the obtained structures and, thus, also the filtration properties, were examined. For tested solutions, i.e., 4% and 6%, the mean fiber diameter decreased as the concentration decreased. Therefore, the overall filtering efficiency increased as the concentration of the used solution decreased. The produced structures exhibited approximately 70% filtration efficiency for particles ranging from 0.02 to 0.2 μm with a pressure drop of less than 60 Pa. Obtained results are optimistic and are a step in producing efficient, biodegradable filters to remove nanoparticles from air.