Science & Technology

Make cleaner and eco-friendly plastics from fish waste

Using fish oil, researchers have created materials like polyurethane. Credit: Mikhailey Wheeler

Polyurethane, a type of plastic, is found almost everywhere in shoes, clothing, refrigerators, construction materials, and more. However, these very versatile materials have major drawbacks. Traditional polyurethanes, derived from crude oil, toxic to synthesis and slow to decompose, are not environmentally friendly. Today, researchers say they should be a safer, biodegradable alternative that comes from fish excrement (head, bone, skin, intestines) and is otherwise likely to be discarded. Discusses devising what to say.


Researchers will present their results today at the American Chemical Society (ACS) Spring Conference.

If developed successfully, fish oil-based polyurethanes can help meet more and more vast needs. Sustainable plasticDr. Francesca Carton, Principal Investigator of the Project, says. “It’s important that we start designing plastics with end-of-life plans, whether that’s the case or not. Chemical deterioration It transforms the material into carbon dioxide and water, or recycling and diversion. “

To make new ingredients, Carton’s team began with oil extracted from Atlantic salmon debris after the fish were ready to sell to consumers. “I find it interesting to make something useful, even changing the way people make plastic, from the trash that people have just thrown away,” said graduate student Mikhail Wheeler, who was presenting at the conference. Both Carton and Wheeler are at Newfoundland Memorial University (Canada).

Traditional methods for producing polyurethane present many environmental and safety issues.Is required crude oil, Non-renewable resources, phosgene, colorless and highly toxic gas. Synthesis produces isocyanate, a potent respiratory irritant, and the final product is not easily degraded in the environment. The limited biodegradation that occurs can release carcinogenic compounds. Meanwhile, the demand for more environmentally friendly alternatives is increasing. Previously, some people used plant-derived oils instead of petroleum to develop new polyurethanes. However, these also have drawbacks. Oil-producing crops, often soybeans, require land that can otherwise be used to grow food.

Leftover fish struck the carton as a promising alternative. Salmon farming is a major industry on the Newfoundland coast where her university is located. After processing the fish, the remaining part is often discarded, but oil may also be extracted. Kerton and her colleagues have developed a process to convert this fish oil into a polymer like polyurethane. First, oxygen is added to unsaturated oils in a controlled manner to form epoxides, which are molecules similar to epoxy resins.After reacting with these epoxides carbon dioxide, They combine the resulting molecules with nitrogen-containing amines to form new materials.

But does plastic smell like fish? “When you start the process with fish oil, you get a faint fish smell, but as you go through the steps, that smell disappears,” says Carton.

Kerton and her team explained this method in a treatise last August, and Wheeler has been tweaking it ever since. She recently succeeded in exchanging amines for amino acids. This simplifies the associated chemistry. The amines they used earlier had to come from cashew nut shells, amino acid It already exists in nature. Wheeler’s preliminary results suggest that histidine and asparagine can embed amines by binding polymer components.

In other experiments, they began to investigate how easily new materials could decompose after their useful life.Wheeler soaked a piece of it in water and added lipase, an enzyme that can break down fats like them, to speed up the breakdown of some pieces. fish oil. Under the microscope, she later confirmed the growth of microorganisms in all samples. This is a promising sign that new materials can easily biodegrade, including samples that were in normal water.

Kerton and Wheeler plan to continue testing the effects of using amino acids in their synthesis and study how sensitive the material is to the growth of microorganisms that may accelerate its degradation. .. They will also study their physical properties to see how they could be used in real-world applications such as packaging and clothing fibers.


From hard to soft: Make a sponge from mussel shells


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Abstract title: Waste fish oil for the production of more environmentally friendly polyurethane materials

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Make cleaner and eco-friendly plastics from fish waste

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