Applications from a single raw material. A, Lot of raw casting products, dried N63. B, N self-supporting film63. C,N6360 spoons and forks. D, Demonstration of N6360 like a stiff spoon to scoop out peanut butter. E, Demonstration of N6360 as a rigid fork to pick up a piece of cheese. F, Demonstration of N63110 as a pressure sensitive adhesive. G, Demonstration of N6360 immediately fails as an adhesive. Credit: Science (2024). DOI: 10.1126/science.adi5009
A team of molecular engineers has developed a type of plastic whose shape can be changed by quenching. In their article published in the journal Science The team, from the University of Chicago, with colleagues from the US Army Research Laboratory DEVCOM, Aberdeen Proving Ground, the National Institutes of Standards and Technology and the NASA Glenn Research Center, describes how they made their plastic and how well it was able to change shape when they applied different types of quenching.
Haley McAllister and Julia Kalow of Northwestern University published a Perspective article in the same issue of Science describing the work.
In recent years, it has become clear that the use of plastics in products is harmful not only to the environment but also to human health: pieces of plastic have been found in the soil, atmosphere, oceans and the human body.
Therefore, scientists began looking for ways to reduce the amount of plastic created, used and thrown into the trash. In this new effort, the research team created a type of plastic that can be transformed into something new once its original purpose has been exhausted: by quenching. A plastic bag containing food, for example, could be transformed into a fork or spoon.
To enable such a shape change, researchers developed a type of plastic using a dynamic cross-linking approach based on the reversible addition of thiols to benzalcyanoacetates, a process known as “Michael addition.” The resulting plastic was a type that could be modified by quenching, which is when a material is heated to a certain point and then cooled quickly. Quenching is most often associated with metalworking.
The researchers found that by heating the plastic to temperatures between 60°C and 110°C, then transferring it to a standard food freezer, they could create different objects from the same material as they fancied them.
They first created a spoon, which they used to scoop peanut butter into a jar. They then used tempering to transform the spoon into a fork, and then into an adhesive material capable of holding two panes of glass together. However, tests showed that there was a limit to the number of times the plastic could be changed, which was seven times. After that it started to deteriorate.
More information:
Nicholas R. Boynton et al, Access to pluripotent materials through quenching of dynamic covalent polymer networks, Science (2024). DOI: 10.1126/science.adi5009
Haley P. McAllister et al, Plastics that go on demand, Science (2024). DOI: 10.1126/science.adn3980
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Quote: A type of plastic that can be modified by tempering (February 2, 2024) retrieved February 2, 2024 from
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