Scientists develop completely biodegradable paper straws

SEOUL: Researchers have developed eco-friendly paper straws that are 100 per cent biodegradable, perform better than conventional paper straws, and can be easily mass-produced.

The paper straws that are currently available are not entirely made of paper. Straws made with 100 per cent paper become too soggy when they come in contact with liquids and cannot function as straws. Accordingly, their surfaces have to be coated.

The researchers from Korea Research Institute of Chemical Technology synthesised a well-known biodegradable plastic, polybutylene succinate (PBS), by adding a small amount of cellulose nanocrystals to create a coating material.

The added cellulose nanocrystals are the same material as the main component of paper, and this allows the biodegradable plastic to firmly attach to the paper surface during the coating process.

The new paper straws do not become soggy easily or cause bubble formation in carbonated drinks because the coating material uniformly and strongly covers the surface of the straws, the researchers said. Also, the coating material is made of paper and biodegradable plastic and therefore will decompose and degrade completely, they said.

''Turning a plastic straw we often use into a paper straw will not immediately impact our environment, but the difference will be profound over time,'' said lead researcher Oh Dongyeop.

''If we gradually change from using convenient disposable plastic products to various eco-friendly products, our future environment will be much safer than what we now worry about,'' Dongyeop said.

The research, published in the journal Advanced Science, found that these eco-friendly paper straws maintain their physical integrity in both cold drinks and hot drinks.

The team also found that the straws did not become soggy when used to stir various beverages such as water, tea, carbonated drinks, milk, and other drinks containing lipids, or upon prolonged contact with liquids.

The researchers compared the degree of sogginess of the new paper straws and conventional paper straws. The conventional paper straw was severely bent when a weight of approximately 25 grammes was suspended after the straw was dipped in cold water at 5 degrees Celsius for one minute, they said.

In contrast, the new paper straw did not bend as much even when the weight was more than 50 grammes under the same conditions. The new straws decompose well, even in the ocean.

In general, paper or plastic decomposes much more slowly in the ocean than in soil because of the ocean's low temperature and high salinity, which impede growth of microbes.