Effect of Different Symmetries of Electrospun Poly(lactic acid) Nanofibers on Facemask Filtration

Abstract

The Covid-19 pandemic has prompted the use of disposable facemasks, which has raised serious environmental concerns. Thus, we developed ultrafine electrospun masks comprising eco-friendly and biodegradable polymer polylactic acid, spun with different degrees of fiber alignments, ranging from random to less, medium, and highly aligned nanofibers. The filtration performance was assessed by penetrating sodium chloride (NaCl) aerosol particles (mean diameter 0.25 μm). The LA-NF samples exhibited a homogeneous network of fibers and thus even pore size distribution. The homogeneity of flow is generally accompanied by a decreased value of pressure drop. Such flow through the gaps (pores) created between the fibers follows Bernoulli’s principle, which revealed an extremely decreased value of pressure drop of 96 Pa and yielded a high filtration efficiency of 99.998% and a Q f of 0.17 Pa–1. The presence of static charges on membranes varies according to the geometry of the surface, which provides a strong electrostatic force between fine particulates and the charged surface. Moreover, a comparative study of static chargeability of the less aligned sample and conventional polypropylene filter was conducted, which revealed mean potential values of 67.1 and 60.8 V, respectively. The outcome implies the superior characteristics of the former, which can be attributed to the surface geometry of the structured membrane.

Preparation of fluffy bimodal conjugated electrospun poly(lactic acid) air filters with low pressure drop

“…This observation aligns with Darcy's law. 38,39 The positive relationship between pressure drop and airflow velocity suggests that the membrane material has open hair channels and exhibits excellent air permeability.…”

Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

“…The outbreak of the COVID-19 pandemic and the escalating air pollution in major cities have highlighted the critical importance and necessity of personal protective facemasks. − Nonwoven fibrous membrane materials made of petroleum-based polymers such as polypropylene (PP) and polyethylene (PE) are serving as the core filtering materials of surgical facemasks and N95 respirators. − However, these materials are nonrenewable, nonreusable, and nonbiodegradable, , contributing to substantial amounts of microplastic pollutants and posing severe hazards to the environment and human beings on the earth. , For instance, since the onset of the COVID-19 pandemic, over 129 billion nonwoven single-use masks have been discarded monthly worldwide, becoming heavy burdens to the environment. The use of nonbiodegradable polymers and single-use patterns of the facemasks in personal protection are the key nonsustainable features.…”

Fabrication of Poly(Lactic Acid)@TiO2 Electrospun Membrane Decorated with Metal–Organic Frameworks for Efficient Air Filtration and Bacteriostasis

“…However, the main drawback is the dissipation of charge during daily use, which results in the unstable filtration of the masks. The nanofiber filtration membrane prepared using the electrospinning method possesses characteristics such as a small fiber diameter [18], a large specific surface area [19], and high porosity [20], making it highly suitable for effectively filtering PM2.5 particles [21]. At the same time, traditional polymer materials used for filtration media are typically derived from non-renewable oil sources.…”