Tuesday, 16 May 2017

A Biodegradable Sanitary Pad Based on a Seaweed Ingredient

The disposal of sanitary pads (or napkins) and related products creates a big environmental problem that needs to be solved. Women need some kind of protection during menstruation. A sanitary pad is a popular choice, but unfortunately most brands are not biodegradable and collect in the environment as waste after use. Researchers at the University of Utah have created a new pad which they say is effective, comfortable, and safe for the environment. It relies on a substance from brown algae or brown seaweed for its ability to absorb liquids.

Brown Algae in Norway
Photo by Ximonic, CC BY-SA 4.0

Each year, nearly 20 billion sanitary pads, tampons and applicators are dumped into North American landfills. (Quotation Source: University of Utah News Release)

Biodegradable Products

Biodegradable products would seem to be a solution for the environmental problems cause by discarded sanitary pads. There are problems with at least some of these products, however. Complaints include the fact that they don't absorb enough fluid, don't fit properly, or are uncomfortable. The researchers at the University of Utah have created what they believe is a "better sustainable sanitary pad".

                            Candida albicans growing on agar in a yeast form
                                            and in a filamentous form.
                                       Photo by Garnhami, CC BY-SA 4.0

The SHERO Pad 

The University of Utah researchers say that their product is thinner than other biodegradable pads. It's known as a SHERO pad and is composed of four layers. The outer layer is made of the same material as tea bags. Below this is a cotton layer that helps to absorb liquid. Next is a highly absorbent substance called agarose, which is obtained from brown algae. The last layer of the pad is made from corn and serves as a moisture barrier.

Agarose is a polymer and a polysaccharide that is obtained from the agar in seaweed. Polymers are long molecules made of repeating subunits. In a polysaccharide, the subunits are sugar molecules. In biology, the word "sugar" refers to a family of chemicals instead of just sucrose, or table sugar. 

Agar (sometimes known as agar-agar) is a substance obtained from certain algae that forms a gel when added to water. It's often supplied to the public in a dried form as a powder or flakes. When water is added to the dried agar, the gel is produced. Agar is used as a vegetarian substitute for gelatin. It's also a common substrate for bacteria in the petri dishes used in biology and medical labs. Agarose is one of the chemicals in agar that is responsible for its ability to form gels.

The inventors of the new pad say that once discarded it will break down within forty-five days to six months. The difference in time presumably depends on the environmental conditions. The pads are said to be completely degradable, unlike some pads that claim to be so. 
The average woman will menstruate for about four decades and use an estimated 16,800 sanitary pads or tampons in the process — that’s 250 to 300 pounds of waste. In the U.S. alone, some 12 billion pads and 7 billion tampons are disposed of annually. (Quotation Source: grist.org)

Creating and Selling the Pad

The SHERO pad was created for women in developing countries, especially those in Guatemala. In fact, its creation was stimulated by a request from a Guatemalan advocacy group for women and children. Safe drinking water and public sanitation are sometimes unavailable in the country, especially in rural areas. Discarded sanitary napkins add to the pollution burden.

The researchers have launched a startup company and hope to have the product available in Guatemala and for sale in the United States within a year. They also say that it may be possible for communities in some parts of Guatemala to produce the pads themselves from local materials, as long as they have a grinding stone and a press. It will be interesting to see how practical this process is. It will also be interesting to see if the pads are as effective and as biodegradable as the researchers believe.


University of Utah News Report 

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