Conventional paper straws are inconvenient to use. Upon prolonged contact with a liquid, they become soggy. Also, when these straws are used to drink carbonated beverages, many bubbles may form owing to their surface properties.
Currently, polylactic acid (PLA) straws and rice straws are available in the market as alternatives to paper straws. However, PLA straws—also known as corn plastic straws—do not decompose well in the ocean.
The joint research team of Dr. Oh Dongyeop and Dr. Kwak Hojung of KRICT and Professor Park Jeyoung of Sogang University have developed eco-friendly paper straws that are 100% biodegradable, perform better than conventional paper straws, and can be easily mass-produced. These straws can quickly become soggy and biodegradable.
According to scientists, these straws are expected to be implemented in response to the regulations on plastic straws in restaurants and cafés.
By combining a little number of cellulose nanocrystals with a well-known biodegradable plastic, polybutylene succinate (PBS)*, the research team’s method was used to develop a coating material. The biodegradable plastic can firmly adhere to the paper surface during the coating process because of the additional cellulose nanocrystals, which are made of the same substance as the major paper component.
The research team discovered that these environmentally friendly paper straws retain their physical integrity in hot and cold beverages. The scientists also found that the straws did not grow soggy when used to stir a variety of liquids, including water, tea, carbonated beverages, milk, and other liquids containing lipids. The sogginess of the paper straws as they were prepared and the traditional paper straws were compared.
The research team performed a decomposition test in a marine environment by immersing the straw samples at a depth of 1.5–2 m on the coast near Pohang, South Korea. They lost more than 50% of their weight after 60 days and decomposed entirely after 120 days.
Head researcher Dr. Oh Dongyeop said, “This technology is but a small step toward the direction we need to take in this era of plastic. Turning the plastic straw we often use into a paper straw will not immediately impact our environment, but the difference will be profound over time. If we gradually change from using convenient disposable plastic products to various eco-friendly products, our future environment will be much safer than we now worry about.”