Contributing to face mask development and testing

The Institute for Research in Innovative Technology and Sustainability (IRITS) received funding from a mask filtration layer manufacturer, Curie Limited, for a project to fine-tune a filtration material developed as an alternative to the traditional meltblown fabric and to look for new applications of this material.

Making use of strongly positively charged fibres to arrest and destroy spike proteins, the new material has undergone pre-production testing and fine-tuning to the highest efficacy in the University's Testing and Certification Laboratory. The final product, now already used in commercial mask production, has been proved to be 99.81% effective in killing the COVID-19 virus. Meanwhile, the project team is looking into other applications of the material, such as in air conditioning systems and clothing items.

In addition, the School of Science and Technology (S&T) performed two other tests on face masks at third-party invitations.

One was a microbiological test on masks with vibrant colours or patterns. The test found substantially more bacteria on these masks than white or traditional plain colour masks after six hours of use. This may be attributed to the application of printing inks, which provide nutrients for microorganisms.

Another test covered six common face masks and six disinfectant products. The test aimed to establish whether bacterial filtration efficiency (BFE) could be affected by heat or humidity. Based on the ASTM F2101 testing standard, two surgical masks of different brands, a bamboo charcoal fibre mask, an N95 respirator, a cotton mask and a photocatalyst mask were tested. It was found that after eight hours of simulated wearing at 37°C and 90% humidity, the surgical masks, the bamboo charcoal fibre mask and the N95 mask still maintained a BFE of over 99%, while the BFE rate of the cotton and photocatalyst masks dropped by 10%.

The test on disinfectants involved a hydrogen peroxide solution, two disinfectant sprays and three alcohol-based hand rubs, and followed test methods for antibacterial-finished products. As it turned out, all specimens exhibited a bacteria-killing rate of over 99%; however, one alcohol-based rub recorded approximately 110 cfu in Staphylococcus aureus residue. That particular hand rub could have been compromised by a reduction in alcohol concentration over time or due to poor storage. Noting that four of the specimens contain antibacterial agents, some of which could cause poisoning through long-term oral ingestion, thus direct contact with food after applying these sanitizers to the hands or using them to disinfect tableware should be avoided.