WOODS HOLE, Mass. — Plastic straws are said to be one of the most common pieces of trash found on our coastlines and researchers on Cape Cod are looking for ways to cut down on the problem.
The Woods Hole Oceanographic Institute says its scientists have helped develop a prototype bioplastic straw - derived from wood pulp - that degrades even faster than a paper straw.
Paper straws are often criticized by consumers for becoming soggy too quickly while being used.
“We lack a firm understanding of how long plastics last in the ocean, so we’ve been designing methods to measure how fast these materials degrade,” said WHOI scientist Colin Ward. “It turns out, in this case, there are some bioplastic straws that actually degrade fairly quickly, which is good news.”
The findings are based on the study of different types of plastics and paper drinking straws that were put head-to-head in tests, to see which degrade the fastest in the coastal ocean.
WHOI says bioplastic manufacturing company Eastman provided funding, supplied materials for the study, and helped co-author the report.
The study involved suspending eight different types of straws in a tank of continuously flowing seawater from Martha’s Vineyard Sound.
“This method also controlled the temperature, light exposure, and other environmental variables to mimic the natural marine environment,” according to the WHOI. “All straws were monitored for signs of degradation over 16 weeks, and the microbial communities growing on the straws were characterized.”
Scientists tested straws made of cellulose diacetate (CDA), polyhydroxyalkanoates (PHA), paper, polylactic acid (PLA), and polypropylene (PP).
Woods Hole says CDA is a polymer product - derived from wood pulp - that is widely used in consumer goods.
The results showed that straws made of CDA, PHA, and paper straws degraded by up to 50% and scientists put their “environmental lifetimes” at 10-20 months in the coastal ocean. The PLA and PP straws showed no measurable signs of breaking down.
Scientists then focused their attention more closely on the straws made from CDA.
One of them was a solid and the other a foam.
“They found that the degradation rate of the foam straw was 184% faster than its solid counterpart, resulting in a shorter projected environmental lifetime than the paper straws,” according to WHOI.
“The unique aspects of this foam straw are that it’s able to have a shorter expected lifetime than the paper straws but retain the properties that you enjoy of a plastic or a bioplastic straw, said WHOI scientist Bryan James.
The WHOI team said the test result makes the prototype straw a promising alternative to conventional plastic straws - compared to paper straws - “which degrade quickly in the ocean but sour user experience by getting soggy.”
“While some push to shift away from plastics, the reality is that plastics are here to stay,” said Ward. “We’re trying to accept the fact that these materials are going to be used by consumers, and then we can work with companies to minimize the impacts of them should they leak into the environment.”
The findings are published in a new paper in ACS Sustainable Chemistry & Engineering.
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