• Hannula, Simo
• Saarimaki, Eetta
• Heikkilä, Pirjo

Abstract

Introduction <br/><br/>Due to increasing need for sustainable products, several bio-based and biodegradable materials have been studied for replacement of fossil-based materials to reduce accumulation of waste into environment, and carbon dioxide emissions during life cycles of individual products. <br/><br/>During recent COVID-19 pandemic, high demand for personal face masks emerged. By using disposable face masks, the spread of infectious respiratory diseases can be effectively halted. With this approach though, there has been a huge problem with waste accumulation due to face masks being disposed into environment after use.<br/><br/>Several candidates for bio-based and biodegradable materials for disposable products have been studied, including polylactic acid (PLA), polybutylene succinate (PBS), PBAT (polybutylene adipate terephthalate) and cellulose acetate (CA). From these materials, polylactic acid was chosen as potential candidate for electrospinning trials. <br/><br/>Electrospinning can be used for production of nano-scale fibres, in production of nonwoven webs. Small diameter of fibres is essential for filtration applications, especially with pathogens in nanoscale.<br/><br/>Goals <br/><br/>The main goal of these trials was to study solubility and suitability of different bio-based polymers for electrospinning, effects of different processing variables, and properties of produced nonwoven webs. Furthermore, produced webs will be further studied for suitability in filtration applications. <br/><br/>Methods <br/><br/>PLA was dissolved into a binary-solvent mixture of chloroform (CF) and dimethylformamide (DMF) in mass ratio of 90/10 in concentrations of 9,70 % and 10,50 % by using heating plate equipped with magnetic stirrer. Input flow by gravitation was used during spinning. The effects of tip to collector <br/>distance, voltage, concentration of solution, and needle size were studied to find processing parameters for good formation of web, minimal defects in fibres, and smallest possible fibre diameter. After spinning, the electrospun samples were analyzed by scanning electron microscope (SEM) imaging. The results were further utilized for production of stand-alone web with sufficiently <br/>low fibre diameter, good fibre density, and sufficient strength for handling.<br/><br/>Results <br/><br/>It was found possible to produce filtration layer with good physical properties, by using bio-based and biodegradable PLA. Further studies for chargeability are required to determine whether produced webs are suitable for filtration applications. <br/>

Topics

• density
• impedance spectroscopy
• polymer
• Carbon
• scanning electron microscopy
• strength
• defect
• cellulose
• electrospinning