Sodium polyacrylate (C3H3O2Na) is a synthetic polymer that can absorb 100-1000 times its dry mass in water. At room temperature it is a white, granular, odorless solid. While sodium polyacrylate is a synthetic polymer, it is not recognized as a plastic but rather as a salt; a sodium salt of polyacrylic acid. Yet, it doesn't actually behave as a salt. Sodium polyacrylate doesn’t fully dissolve in water but instead absorbs it, swelling into a gel-like substance. When it comes into contact with water, sodium polyacrylate's sodium ions partially dissociate, allowing water molecules to bind within the polymer structure. However, the polymer itself remains as a network, rather than breaking down into individual molecules in solution.
At room temperature, dry sodium polyacrylate is a white, granular, odorless solid. that can absorb up to 1000 times its dry mass in water.
Each year, over 2 million tonnes of sodium polyacrylate is produced; 74% of which, is claimed by the disposable diaper market. This corresponds to roughly 0.5% of all plastic production. Diapers are notoriously difficult to recycle, and they almost always end up in landfills without substantial biodegradation. Sodium polyacrylate is deemed safe and non-toxic, with no significant risks. Nevertheless, there is insufficient data regarding its environmental safety. whats more, it is recognized as non-biodegradable and could potentially lead to soil salinization if used in excessive amounts.
74% of all sodium polyacrylate (1.5 million tonnes) is used in the production of disposable diapers which almost always end up in landfills.
The remaning 26% of sodium polyacrylate production, is used for retaining moisture in potted plants and soils. As a sequestering/chelating agent in detergents, a thickening agent, and in coatings (protects electrical and optical cables from moisture)...As well as in the production of fake snow... Sodium polyacrylate has even been considered to be used for microencapsulation to deliver substances like probiotics to people.
Sodium polyacrylate is intentionally added to agricultural soils to increase water rentention properties, despite being a synthetic polymer that does not easily degrade in nature.
Since its invention in the 1960's, sodium polyacrylate has been mixed with agricultural soils to increase water rentention properties Since, sodium polyacrylate is not inherently toxic, according to the FDA, this practice has not been questioned, until recently. The environmental impact of sodium polyacrylate primarily concerns its potential soil and aquatic toxicity, as well as its contributions to microplastic pollution. Over time, sodium polyacrylate may degrade into smaller particles, contributing to microplastic pollution, because they never fully dissolve in water. Studies show that while sodium polyacrylate can improve soil water retention and aid plant growth, its persistence and degradation raise concerns. Specifically, sodium polyacrylate breakdown products may inhibit microbial activity, leading to altered soil ecology and nutrient cycles. Once in the soil, sodium polyacrylate is effectively impossible to remove.
Dyed sodium polyacrylate hydrogel beads used a childrens' toys. The application and waste management of sodium polyacrylate is very lightly controlled, but the polymer does not easily degrade in nature and may cause harm to the environment in the long run. (Image: Wikipedia).
The environmental persistence of sodium polyacrylate may pose long-term issues. The polymers resist biodegradation, meaning they can persist in both terrestrial and aquatic environments, posing potential ingestion risks to various species. Efforts to assess and mitigate these risks are ongoing, but comprehensive regulations are currently limited, and sodium polyacrylate's environmental fate remains an area of active research and debate.
Sodium polyacrylate in dry form.
Essentially, sodium polyacrylate is a plastic that has been branded as a salt due to its water-absorbing properties. Further research is required to prevent causing permanent harm to soils and nearby aquatic ecosystems.
Comments