The filtering material for disposable medical protective masks is essentially a type of plastic. Improper disposal of discarded disposable medical protective masks can lead to environmental problems, while using biodegradable materials to make disposable medical protective masks can effectively alleviate their pressure on the ecological environment.
Disposable medical protective masks have become an essential item in people’s daily lives. According to the World Health Organization, at least 129 billion masks were produced globally in 2020, with the majority being disposable medical protective masks. If not handled properly, these masks will pose a serious threat to the ecological environment. Recently, Gao Fu, an academician of the CAS Member and chairman of the Chinese Society of Bioengineering, called at the 15th China Bioindustry Conference held in Wuhan, Hubei Province, that the current biological industry urgently needs to promote the combination of industry, education and research, promote the application of biodegradable materials in disposable medical protective masks, and reduce the environmental burden.
What are the common biodegradable materials that can be used to produce disposable medical protective masks? How can these materials achieve both filtering of harmful substances and degradation? Has the industrial application of biodegradable disposable medical protective masks been achieved? With these questions in mind, a reporter from Science and Technology Daily interviewed relevant experts.
Abandoned disposable masks pose a threat to the environment
Disposable medical protective masks (hereinafter referred to as masks) generally consist of three parts: face mask, mask strap, and nose clip.
Zheng Yang, Director of the Hazardous Waste Management Technology Department at the Solid Waste and Chemical Management Technology Center of the Ministry of Ecology and Environment, said that the mask part of a mask is generally divided into three layers, with the outermost and innermost layers made of non-woven fabric and the middle layer made of meltblown fabric. Although these three layers have different names, their main raw material is polypropylene (PP), which belongs to non degradable plastics.
The “product structure composition” of masks, in addition to the mask being made of polypropylene, the main material of the mask strap is also polypropylene non-woven fabric. The nose clip is wrapped in polyethylene (PE) to wrap the thin wire, which is also a non degradable plastic.
Improper disposal of discarded masks can lead to environmental problems. If this type of mask is thrown into the natural environment, the degradation time may take several decades to several hundred years, “Zheng Yang said. Professor Ding Xuejia from the School of Materials Science and Engineering at Beijing University of Chemical Technology also stated that the filter material for masks is essentially a type of plastic that takes up to 450 years to decompose.
According to an analysis report, in 2020, at least 1.56 billion masks flowed into the ocean due to improper handling, and some abandoned masks invaded the habitats of wildlife. A large number of discarded masks will directly affect the survival of marine organisms, birds, as well as fisheries, aquaculture, and other industries.
The harm of discarded masks to the ecological environment goes beyond what is visible to the naked eye. Compared with other materials, meltblown fabric and non-woven fabric have extremely fine fiber diameters, and the use of masks exacerbates mechanical wear between fibers, forming more microplastics. Research has shown that unused masks release an average of 71-308 microplastics per mask; After use, the average release of microplastics from masks increased to 682-1918 per mask. In the ocean, these microplastics are easily ingested by organisms such as fish and shrimp, entering the food chain and ultimately entering the human body.
Using polylactic acid to make biodegradable masks
Ding Xuejia said that using biodegradable materials to make masks can effectively alleviate the pressure of discarded masks on the ecological environment.
Currently, there are multiple biodegradable masks available in the domestic market, mainly made of polylactic acid (PLA). For example, the fully biodegradable lactic acid environmental masks produced by Bengbu Fengyuan Tushan Pharmaceutical Co., Ltd. use biodegradable material polylactic acid instead of polypropylene. Masks made from this material can decompose into water and carbon dioxide in natural environments without increasing ecological burden. The bio based biodegradable masks produced by Natong Medical Protective Equipment (Tianjin) Co., Ltd. are mainly composed of polylactic acid. The nose clip is a blend of polylactic acid and polybutylene adipate terephthalate (PBAT), and the mask strap is a blend of polylactic acid and spandex. These materials can be composted and degraded, with a degradation cycle of about 6 months.
Why can polylactic acid become the main material for biodegradable masks?
The “Report on the Development of Polylactic Acid Fiber Industry” (hereinafter referred to as the “Report”) written by the China Chemical Fiber Industry Association shows that polylactic acid has good mechanical properties, moisture absorption and breathability, antibacterial properties, as well as good biodegradability and biocompatibility. The fabrics made of polylactic acid have a soft hand feel… These properties make polylactic acid widely used in fields such as clothing, home textiles, and medical hygiene materials.
Wang Yongsheng, Deputy Director of the Marketing Department of the China Chemical Fiber Industry Association, said that under normal temperature and humidity, polylactic acid and its products are quite stable. But in natural environments with certain temperature and humidity, such as sand, silt, and seawater, polylactic acid can be completely degraded by microorganisms in nature, and eventually decomposed into water and carbon dioxide.
Polylactic acid has 100% biocompatibility and is a safe and non irritating polyester substance. Even if it enters the human body, it can be completely decomposed into water and carbon dioxide in the body, and then excreted from the body through circulation. During its decomposition process, the intermediate product lactic acid produced is also a substance produced by human muscles, which can be absorbed by the human body as a carbon source and is completely non-toxic, “said Li Zengjun, Chief Economist of the China Chemical Fiber Industry Association and Secretary General of the Biobased Fiber Professional Committee of the China Chemical Fiber Industry Association.
In the development and use of biodegradable masks, there are various technological routes besides polylactic acid. The Korean Academy of Science and Technology has developed a functional and biodegradable polymer filter membrane, which is composed of PBAT matrix mixed with cetyltrimethylammonium bromide (CTAB) and montmorillonite (MMT) clay. During electrospinning, the membrane can spontaneously evolve and amplify antibacterial and antiviral activities on the material surface, as well as retain the static electricity of adsorbed dust and droplets for a long time.
Two biotechnology researchers from Jakarta Mada University in Indonesia have proposed that biodegradable disposable masks can be made from pineapple leaves. Due to the use of natural fibers from pineapple leaves instead of plastic, it can be rapidly degraded by microorganisms after entering the soil.
The industrialization of biodegradable materials faces challenges
However, the industrial application of biodegradable materials such as polylactic acid still faces many challenges. The report shows that under the promotion of plastic ban and restriction, polylactic acid has become a hot topic in China’s industry development. In 2022, China’s polylactic acid fiber production capacity reached 98000 tons, and the industry grew rapidly. The polylactic acid industry chain integrates technologies such as biological fermentation, chemistry, chemical engineering, and polymer material processing, and has the characteristics of high technological threshold and high degree of technological integration. At present, the overall polylactic acid industry in China is still in its infancy, and large-scale, low-cost, and high-performance technologies urgently need to be improved.
In January 2023, six ministries including the Ministry of Industry and Information Technology issued the “Three Year Action Plan for Accelerating the Innovative Development of Non Grain Biomass Materials”, proposing that by 2025, the utilization and application technology of non grain biomass raw materials will be basically mature. Currently, the main raw material for polylactic acid is starch. Li Zengjun said that under the principle of “not competing with people for food and land”, the application and development of straw, corn cob, biomass glycerol, etc. should be carried out to broaden the sources of polylactic acid raw materials.
Wang Yongsheng said that the scale of polylactic acid production enterprises in China is relatively small and the production cost is high. It is urgent to solve the problems of diversification and localization of polylactic acid raw materials, fill the gaps in polylactic acid polymerization and preparation technology, and reduce production costs.
Currently, polylactic acid is mainly used in textile and clothing, daily packaging materials, agricultural film, masks and other fields. Wang Yongsheng said that we should leverage the strengths and avoid weaknesses, give full play to the performance characteristics and advantages of polylactic acid, and develop downstream products in a targeted manner. We should attach importance to the driving role of downstream applications, and in response to the small scale of polylactic acid applications, promote the coordinated development of upstream and downstream industries such as research and development, production, application, and equipment, further expand the scale of polylactic acid applications, and improve its effective supply capacity.
Dongguan Liansheng Non woven Technology Co., Ltd. was established in May 2020. It is a large-scale non-woven fabric production enterprise integrating research and development, production, and sales. It can produce various colors of PP spunbond non-woven fabrics with a width of less than 3.2 meters from 9 grams to 300 grams.
Post time: May-20-2025