Polyurethane foam made from seaweed oil can be used in flip flops

As the most popular shoes in the world, the proportion of flip flops in waste plastics in landfills, coasts and oceans is worrying. Scientists at the University of California, San Diego have spent several years solving this problem, and now they have taken another step toward achieving this goal. Through chemical reactions, the research team formulated a polyurethane foam made of seaweed oil to meet commercial specifications for flip-flop midsoles and foot beds. Their research results were published in the "Bioresources Technical Report" and described the research team's successful development of these sustainable, end-consumer, biodegradable materials.

The research is a collaboration between the University of California, San Diego and the start-up company Algenesis Materials. The project was jointly completed by Professor Michael Burkart from the Department of Physical Sciences, graduate student Natasha Gunawan from the laboratory of Professor Stephen Mayfield from the Department of Biological Sciences, and Marissa Tessman from Algenesis. Mayfield said: "The paper shows that we have commercial quality foams that are biodegradable in natural environments. After experimenting with hundreds of formulations, we finally found a formulation that meets commercial specifications. These foams have a biological content of 52%. , And eventually we will reach 100%."

In addition to designing the correct formula for commercial-quality foam, the researchers also worked with Algenesis to not only manufacture the shoes, but also conduct degradation tests on them. Mayfield pointed out that scientists have proven that commercial products such as polyester, bioplastics (PLA) and fossil fuel plastics (PET) are biodegradable, but only in laboratory tests or industrial composting. Mayfield explained: "Theoretically, we have re-developed polyurethane with bio-based monomers from the ground up to meet the high material specifications of the shoes while maintaining the appropriate chemical properties, so the shoes are biodegradable."

By immersing the customized foam in traditional compost and soil for testing, the team found that the material degraded after only 16 weeks. During the decomposition, to test its toxicity, a team of scientists led by Skip Pomeroy of the University of California, San Diego measured every molecule released from the biodegradable material. They also identified the organisms that degraded foam. Mayfield said: "We extracted enzymes from the foam-degrading organisms, showing that we can use them to depolymerize these polyurethane products, and then determine the intermediate steps that occur in the process. Then we proved that we can separate the depolymerized products, and Use them to synthesize new polyurethane monomers to complete a'biological cycle'."

Making full use of the recyclability of commercial products is the next step in the ongoing task of scientists. The task is to solve the production and waste management problems that we currently face when using plastics. If these problems are not solved, landfills or the natural environment by 2050 It will produce 13 billion tons of plastic. According to Pomeroy, this environmentally unfriendly practice began with the development of plastics about 60 years ago. Algenesis President Tom Cooke said, “We happened to do what we were supposed to do at the right time.” The team also established the Renewable Materials Center of the University of California, San Diego, which is composed of Burkart, Mayfield, Pomeroy and co-founder Brian. Palenik (Scripps Institute of Oceanography) and Larissa Podust (Skaggs School of Pharmacy and Pharmaceutical Sciences) initiated.

Mayfield said: "The life of the material should be proportional to the life of the product. We only need to use the product for one or two years and do not need to use the material that needs to be degraded for about 500 years." With the exception of Gunawan, Burkart, Pomeroy and Mayfield, "Biological Resources" The co-authors of the Technical Report paper include Tessman, Ariel Schreiman (Biological Sciences Department), Ryan Simkovsky (Biological Sciences Department), Anton Samoylov (Chemistry and Biochemistry Department), Nitin Neelakantan (Algenesis Materials Corporation) and Troy Bemis (Chemistry and Biology) Department of Chemistry). This research was funded by Algenesis Materials from the Office of Energy Bioenergy Technology and the National Science Foundation. Burkart, Mayfield and Pomeroy are all co-founders of Algenesis and own equity. In addition, Burkart and Pomeroy are scientific advisors, and Mayfield is the acting CEO and board member.