Recycling Discarded Facemasks of COVID-19 Pandemic to New Novel Composite Thermal Insulation and Sound-Absorbing Materials

Abstract

The COVID-19 pandemic has forced the whole world to wear single-use disposable facemasks for health protection. Studies have shown that about 129 billion facemasks are wasted each month, which will contaminate the environment and create a big problem in getting rid of them. These discarded facemasks are usually dumped in garbage bins, in landfills, or in some cases littering them on the streets, which creates a health hazard to human beings. In order to solve such environmental problems, the current study presents new novel composite materials developed by recycling discarded facemasks. These materials have great potential to be used for both thermal insulation and sound-absorbing for building walls. Experiments have been performed to make bound composite materials using the discarded facemasks as new raw materials with wood adhesive as a binder. The discarded facemasks were first heated for one and half-hour at 120 °C to kill any contaminants (biological or others). Five different composites are made: the first uses the complete facemasks, the second uses facemasks with iron nose clip only, the third uses facemasks with no both ear loops and iron nose clip, the fourth one contains the elastic ear loops only, and the fifth one has facemasks with elastic ear loops only. Coefficients of thermal conductivity for the five samples are obtained as 0.0472, 0.0519, 0.05423, 0.0619, 0.0509 (#5, e), and 0.04347 (#5, f) W/m K at 25 °C, respectively. The sound-absorbing coefficient for samples 1, 2, and 3 is above 0.5 in general and, at some frequencies, approaches 0.8. Results show that the soft samples with low binder concentration have a good sound absorbing coefficient at high frequency, while the one with high binder concentration has that at a low frequency for the same facemasks’ mass. Mechanical properties of all samples are also reported by performing the three-point bending moment. Composite samples have a low moisture content (0.2%) and have high thermal stability up to 325 °C. These composite samples could replace the petrochemical and synthetic thermal insulation materials and, at the same time, get rid of the huge discarded waste facemasks, which is considered a huge environmental problem.