Mandi: Indian Institute of Technology Mandi researchers have developed indigenous technology for manufacturing high-efficiency face masks from waste ‘PET bottles’. Dr. Sumit Sinha Ray, Assistant Professor, School of Engineering, IIT Mandi, along with his research scholars, Mr. Ashish Kakoria and Mr. Sheshang Singh Chandel, have used waste plastic bottles to develop a single thin layer of nano-nonwoven membrane that provides desirable particle filtration efficiency, at par with N95 respirator and a medical mask. The product has been developed and tested in the Multiscale Fabrication and Nanotechnology Laboratory at IIT Mandi.
A human hair is close to 50 micrometres (0.05 mm) thick, the nanofibre membrane developed at IIT Mandi contains fibres which are 250 times thinner than a human hair. A single thin layer of nano-nonwoven membrane used in the masks developed by the research team can remove particles from the air at the critical size of 0.3 micron with more than 98% efficiency. These particles are also called the most penetrating particle and are the most difficult to catch. With this, the researchers envisage replacing the commercially available melt-blown fabric masks which contain microfibre with these ultra-fine nanofibre-based masks.
Speaking about the innovation, Dr. Sumit Sinha Ray, Assistant Professor, School of Engineering, IIT Mandi, said, “Nanofibres can do wonders for facemasks. Air-borne particulate and pollutant removal efficiency and breathability are two main criteria for efficient face masks. Commercially available melt blown fabric-based masks can be efficient at a cost of high breathing resistance, whereas generic 3-ply surgical masks are breathable but have meagre efficiency. Nanofibres based masks can filter out small particles effectively despite being comfortably breathable. We hope to find interested industrial partners to take this technology for large scale production.”
To achieve this, Dr. Sumit Sinha Ray and his team used ‘Electrospinning’ in which the researchers shredded the waste plastic bottles (PET) and dissolved the pieces using a combination of solvents and extruded the nanofibres from the solution. These nanofibres meet the safety requirements of the user by excluding the bacteria and infectious components. The breathability in the developed masks is better than the commercially available masks. Dr. Sumit Sinha Ray has filed a provisional patent for the waste plastic bottle derived filter membrane technology based on electrospinning.
At the laboratory scale, the material cost for the mask can be around Rs. 25/pc. However, during the commercial manufacturing stage, its cost will be nearly halved.
Speaking about the efficacy of the developed mask, Mr. Ashish Kakoria, Research Scholar, IIT Mandi, said, “These ultrafine fibres allow less resistance in airflow due to a unique phenomenon, what we call as the ‘slip flow’, which improves breathability. Moreover, the thrown away PET bottles can be put to good use using this technique.”
Waste plastic pollution has already posed a grave challenge for researchers across the globe. To add to it, production and consumption of plastic-based commodities have increased since COVID-19 pandemic. Researchers at IIT Mandi are trying to mitigate the plastic pollution and come up with a value-added product using the same plastic waste. The developed technology has many other applications as well including smoke filtration and regular air purification.
Nanofibre incorporated 3 ply semi reusable mask
Apart from this, Dr. Sumit Sinha Ray and his research scholars have also developed an efficient nanofibre incorporating a 3-ply semi reusable mask using a membrane made out of Nylon which boasts free-standing nano-nonwoven architecture. These membranes have individual fibres of diameter 0.5 micron and basis weight of 20-25 Grams per Square Meter (GSM). Such membranes were stitched between two thin cotton fabrics to manufacture a face mask with the help of EWOK Society at IIT Mandi.
These masks are more efficient than 3-ply medical face masks in capturing airborne particulates at a similar breathability scale. As of now, at laboratory scale, the team is able to manufacture 20 mask membranes per day which shall be increased as per demand. The nanofibre incorporated 3-ply semi-reusable masks are washable and reusable for several times. At the laboratory scale, the material cost for these masks is Rs. 12/pc.