Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks

In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale

Introdurre la nozione di funzione con l'algebra dei segmenti di Cartesio

Prima della creazione del calcolo differenziale, una tappa fondamentale nella trattazione matematica delle quantità variabili è la Géométrie di Cartesio (1637), in cui viene introdotta l’algebra dei segmenti. Si tratta di un’algebra con i simboli ma senza i numeri in cui la covariazione tra variabili geometriche, vincolate da costruzioni con riga e compasso o con altre costruzioni geometriche, si può esprimere con equazioni simboliche. Le manipolazioni algebriche permettono di dedurre facilmente le proprietà delle corrispondenti costruzioni geometriche, tra cui quelle che producono i grafici delle funzioni razionali. Crediamo che lo studio delle funzioni con l’algebra di Cartesio possa essere didatticamente efficace nell’insegnamento e apprendimento del concetto di funzione nella scuola secondaria di secondo grado perché, in primo luogo, evita il riferimento ai numeri reali e inoltre, interpretando le formule come costruzioni geometriche e viceversa, facilita il passaggio dalle funzioni intese come processi alle funzioni intese come oggetti

Electrospinning technology for scalable manufacturing of polymer-based nanofibers filters with high-performance in submicron particle filtration and bactericidal activity in advanced face mask

In the recent years, Electrospinning (ES) proved to be an easy and advantageous technique to design functionalized nanofibers mats based on natural and synthetic polymers as well as hybrid bioactive nanomaterials, which can be easily implemented for the realization of advanced wearable healthcare devices, scaffold in tissue engineering, energy harvesting system, etc. In particular, the great advantages to obtain nanofibers with tailored diameter sizes and surface characteristic properties, down to the nano scale, has made this methos commercially attractive to produce ecofriendly and more sustainable high filtering devices for facemask application, especially in the last years when the pandemic outbreak of the Coronavirus disease (COVID-19) have brought to a mass consumption of personal protective equipment (PPE) that resulted in a potential source of further contamination from bacteria or virus. The use of modified electrospinning set-up can be an innovative way to manufacture nanofiber-based membrane showing high filtering performance against submicron pollution particles and suitable antibacterial properties for tackling the current issues from bacterial contamination on PPE surfaces to the reusability of both disposable single use facemask and respirator’s filters

AB5/ABS composite material for hydrogen storage

AB5 metal hydride (MH) particles were polymer dispersed in order to entrap the micro and nanoparticles produced by repeated fragmentations of the metal phase during the hydrogen charging/discharging cycles. Acrylonitrile-buta diene-styrene copolymer (ABS) was selected as a matrix on the basis of its physical and chemical properties. AB5/ABS composite pellets were obtained by using a dry mechanical particle coating approach in a tumbling-mill apparatus and successive consolidation by uniaxial hot pressing. A number of characterization techniques were used to assess the morphological, chemical and structural properties of the composites. High pressure DSC measurements, conducted at different pressure values, were used to assess the H(2) absorption properties and profile the Van't Hoff plots of the material. The overall results indicated that the AB5/ABS composite well tolerated the hydriding effects on metal particles, with no losses in hydriding kinetics. The material characteristics were found to be compatible with its application in developing MH-based H(2) storage devices. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved

Electrospinning technology to upscale the production of low-cost and high-filtering functionalized polymer-based nanofibers providing photocatalytic activity for bacterial inactivation in advanced face mask

The importance to produce polymer-based membranes with suitable self-cleanable properties in preventing high risk of contamination on the fabric for long time usage has been becoming a relevant issues, especially in the last years when the pandemic outbreak of the Coronavirus disease (COVID-19) have brought to a mass consumption of personal protective equipment (PPE), such as face mask/respirators, which resulted in a potential source of further contamination from bacteria or virus. Modified electrospinning set-ups combined with modern textile techniques turned out to be an innovative way to manufacture nanofiber-based membrane showing high filtering performance against submicron pollution particles and suitable bioactive properties for tackling the current issues from bacterial contamination on PPE surfaces to the reusability of both disposable single use facemask and respirator’s filters [1]. With this paper we aim to provide further insight about the development of advanced electrospun nanofibrous photocatalytic membranes for large scale production. Investigation on the effects of processing variables on the fabrication of functionalized electrospun nanofibers embedded with active NPs for the scale-up line have been carried out by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Atomic Force Microscopy (AFM), and Raman spectroscopy analysis. In addition, photocatalytic disinfection for some bacteria strains, were conducted on the hybrid polymer-based membranes under UV-A light exposition by using the pristine electrospun membranes as control in the colony count method [2]. Finally, to provide a real perspective for the application of nanotextile in the manufacturing of advanced face mask on large-scale, both particle filtration and breathability test were also conducted on the nanofiber mats, in accordance with the standard required for Filtering Face Piece masks (FFP). [1] Cimini A., E. Imperi, A. Picano, M. Rossi. Electrospun nanofibers for medical face mask with protection capabilities against viruses: State of the art and perspective for industrial scale-up. Applied Materials Today, 2023, (32) 101833. [2] Q. Li, Y. Yin, D. Cao, Y. Wang, P. Luan, X. Sun, W. Liang, H. Zhu, Photocatalytic rejuvenation enabled self-sanitizing, reusable, and biodegradable masks against COVID-19, ACS Nano, 2021, 15 (7), 11992–12005