As the Corona Virus continues to hold it’s grasp on the world, many are looking for ways to keep safe, especially as new variants arrive and schools re-open. Some ways that people have worked to protect themselves and their loved ones is by social distancing, gloves, vaccines, and especially masks. In this modern day, masks are seen as a daily necessity, leaving your house without a mask in your pocket is almost unimaginable. In addition, children wear masks almost all day long due to the opening of schools. So the question of today is what is a mask made out of? It may seem like a simple question, but we wear our masks almost everyday and still very few truly know the structure and material of the fabric they breathe into daily.

This blog will focus mostly on the blue surgical masks that may be seen on most of the population, although, we will lightly touch upon other masks in the future.

Masks weren’t always the light blue pieces of non woven material we see today, in fact masks were once just strips of cloth woven for surgeons as a general face covering. Now masks are used for medical personnel but also for the general public. As well, most surgical masks are no longer made from clothes but instead polymers and they are available in a wide range of styles and colors. Masks are used for sterilizations and the prevention of the spread of germs. Masks in fact do not filter viruses, such as the Corona Virus. Instead, masks block your germs from getting onto others. In addition to the many different types of masks, there are as well, several types of levels of a mask. There are Four levels of ASTM certification for surgical masks. ASTM is the American society for testing materials. The ASTM foundation “develops and delivers voluntary consensus standards designed to improve product quality, make products safer, improve international standardization and therefore facilitate trade.” The four levels are, minimum protection, level 1, level 2, and level 3.

  • Minimum Protection: Not meant for long periods of time and not for liquids or sprays
  • Level 1: Masks at level 1 protection are standard surgical masks featuring ear loops. They are generally meant for low risk situations with a fluid resistance of 80mmHg, so they are not meant to be used against fluids, sprays, and aerosols.
  • Level 2: Masks at level 2 have a 120mmHg fluid resistance. Henceforth, they only reflect light to moderate aerosol, fluid, and spray.
  • Level 3: Masks at level 3 have a 160mmHg fluid resistance. Henceforth, they can deflect heavy amounts of aerosol, fluid, and spray.

These levels are tested with five performance tests for masks. These are bacterial filtration efficiency, differential pressure, sub-micron particulate filtration, resistance to penetration by synthetic blood, and flammability.

  1. Bacterial Filtration Efficiency: Is determined by comparing the bacterial control counts to test article effluent counts. (BFE) – Test ASTM F2101
  2. Breathability: Determines a mask’s resistance to air flow. It is called differential pressure because a controlled stream of air is driven through the mask and the difference of pressure from one side to the other. Test MIL-M-36954 C: ΔP
  3. Particle Filtration: This test measures the amount of bacteria that are larger than 1 micron that are filtered with the mask. (PFE) – Test ASTM F2299
  4. Fluid Resistance: Measures the amount of fluid (~2 mL) that goes through the mask at a high pressure (80mmHg, 120mmHg, and 160mmHg. Directly related to the levels of a mask.). This specific rest is decided through pass or fail. Test ASTM F1862.
  5. Flammability: During the flammability test, the mask is exposed to a flame at a distance of 127mm (5inches) and the time it takes for the flame to proceed up the mask is measured. Test 16 CFR Part 1610: Flame Spread


Masks are most commonly made of a material known as polypropylene. Polypropylene is a “thermoplastic” polymer. Masks may also be made of polystyrene, polycarbonate, polyethylene, and polyester. They are also all thermoplastics. Although some articles have stated that masks have trace amounts of formaldehyde, a colorless, odor full, and flammable chemical used in many laboratories as disinfectants, it is very uncommon to find a mask that has been made from the material. Another material known as toluene is not used in the masks itself, but is used to test different antimicrobial agents that can filter out carbon and other pollutants when used. In addition, unlike some may believe, masks do not contain polytetrafluoroethylene (PTFE). Masks are neither sprayed with PTFE nor is the filter within the mask made of PTFE, although most air filtration is.


Polypropylene is a thermoplastic made of a combination of propylene monomers with a chemical formula of (C^3H^6)n. It may also be classified as a thermoplastic, which has to do with the way the plastic is heated. It must be heated, cooled, and reheated without a significant degradation. Instead of burning thermoplastics liquify, their melting point is about 130 degrees celsius. Polypropylene is also relatively slippery giving it a low friction so it may be used for gears. It also has a lower surface friction than most other materials, making it hard to bond with other surfaces. Although it is slippery on a molecular bases; it has a high friction coefficient. In addition, Polypropylene is of low density compared to other plastics. This makes it very weight saving for manufacturers. Polypropylene may also be manufactured into a living hinge. A living hinge is a cap of a shampoo and ketchup bottle (bendable plastic). The material may be cut extremely thin pieces of plastic that bend without breaking. Although, it is not structurally sound and should not be used for architecture. Polypropylene’s ability of being bent repeatedly without breaking gives it the characteristics of a living hinge. Lastly, it may be easily copolymerized with other polymers such as itself. Furthermore, polypropylene hold’s many characteristics.

  • Chemical Resistance: polypropylene is very resistant to chemicals. It may come in contact with diluted bases and acids but won’t react. This makes it a wonderful material to be used with cleaning products and air products.
  • Elasticity and Toughness: Whilst polypropylene may be extremely elastic, the plastic will retain plastic deformation, although it is a relatively tough plastic.Polypropylene will also experience fatigue resistance, meaning that the material will maintain its shape even after torsion, bending, or flexing. This characteristic makes polypropylene a wonderful living hinge.
  • Insulation: Polypropylene is highly resistant to electricity. This has led the material to be used in a wide range of electrical components.
  • Transmissivity: Although polypropylene may be transparent, it most often comes in color. Additionally, it may also be used for transfer of light, but it is not the top choice for high transmissivity.


Polytetrafluoroethylene, also abbreviated as PTFE, is a strong, tough, waxy, non flammable synthetic resin made with polymerization of tetrafluoroethylene. PTFE has a high melting point and resistance to chemicals. Tetrafluoroethylene with a chemical formula of C^2F^4 is a colorless, odorless, gas made from chlorodifluoromethane which is obtained by reacting hydrogen fluoride (HF) with Chloroform (CHCl^3). In fact, Tetrafluoroethylene has the lowest coefficient of any solid.

How Surgical Masks are Made

Surgical masks are made from non-woven materials. Bacteria filtration and air permeability while remaining less slippery than woven clothes. Masks, most commonly made from polypropylene, have a 20 to 25 grams per square meter density. 20 gsm mask materials are made in a spunbond process, making the fibers less than a micron in diameter. The spunbonding process is a one step manufacturing process. The spunbond process requires a web formation, web bonding, and winding into rolls. At first, melted polystyrene is extruded and forced through a spinneret, the fibers are then stretched and cooled. After, the fibers are continuously placed at a depth slightly larger than the necessary final product and moved onto a conveyor. The loose web created may be bonded with either mechanical bonding, thermal bonding, or chemical bonding. Masks are multilayered structures, generally made by covering a layer of textile with a non woven bonded material on both sides. Non woven materials are both cheaper and cleaner making them more attractive towards manufacturers. Disposable masks often have only two layers, making them effective at filtering about one micron. Although, filtration depends on fiber, manufacturing, fiber structure, and the fiber’s cross-sectional shape.