Environment

Non-soggy biodegradable drinking straws made from wood waste

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Conventional plastic straws (pictured) may seem insignificant, but they actually make up a major source of plastic pollution on a global basis
Depositphotos
Conventional plastic straws (pictured) may seem insignificant, but they actually make up a major source of plastic pollution on a global basis
Depositphotos
A batch of the lignin-based straws
Adapted from ACS Omega, 2023, DOI: 10.1021/acsomega.2c07797

Although disposable plastic straws are being phased out in some countries, their "greener" replacements have a few shortcomings of their own. Well, scientists have now developed bioplastic straws that don't get soggy, but do biodegrade when discarded.

While we have seen other experimental eco-friendly straws, some (such as those made of paper) break down when wet, while others (such as those made of sugar cane) require complex production processes. Non-disposable multi-use straws are certainly one alternative, although not everyone is always going to have such a straw on them whenever they grab a drink while out and about.

With these limitations in mind, scientists from South Korea's Inha University looked to lignin, a type of organic polymer which makes up much of the support tissue in plants – including trees.

It's also a byproduct of the pulp and paper industry, and has previously been put forward for use in applications such as cheaper batteries, waste-derived carbon fiber and stronger concrete.

The researchers combined lignin with either potato starch or plant-derived polyvinyl alcohol (PVA), then added citric acid to that mixture. They then spread the slurry into a thin sheet, rolled that sheet into a cylinder and allowed it to dry, then heated the cylinder in a vacuum at a temperature of 180 ºC (356 ºF).

A batch of the lignin-based straws
Adapted from ACS Omega, 2023, DOI: 10.1021/acsomega.2c07797

The resulting bioplastic self-sealed along the seam, forming a long, skinny tube that was cut into individual flexible straws. Those straws didn't become soggy when immersed in liquid, and were in fact even stronger than conventional polypropylene straws. That said, while the traditional straws remained unchanged after being left outside and exposed to the elements for two months, the lignin straws had significantly biodegraded.

A paper on the study – which was led by Dickens Agumba, Duc Hoa Pham and Jaehwan Kim – was recently published in the journal ACS Omega.

Source: American Chemical Society

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6 comments
Tristan P
So, will they be safe to use for food based uses? Like sucking liquids for ingestion.
Trylon
Or you could either buy a reusable straw (silicone, stainless steel, aluminum, etc.) and ditch the disposable mentality, or maybe even eschew straws altogether.
myearwood
Well they did not ban the plastic lid when they banned the straw. Can this lignin based plastic replace both and the cup? That's progress.
CarolynFarstrider
The more sustainable option would be to consider if you need to use a straw at all! For most drinks, you can just sip from the cup….
1stClassOPP
All good comments, I think, but allow me to wade in. My wife uses some type of pasta., some of which is hollow. Why not develop pasta into a “straw” ? It should stand up for cold drinks, I guess. After use, could be used as a nutritional meal when cooked. Good?
Dan
Straws are the last thing we should be concerned about. Scientists, spend your time on substantial things like plastic packaging, tires, pollutants, and dirty energy. Then worry about silly straws, which are inconsequential by comparison. A waste of time and resources.