I think that I’m right when I say that we see plastics or plastics components everywhere which is perfectly normal because this type of material is one of the most amazing ever. Only carbon nanotubes seem to be so „futuristic”, however, plastics are tough, durable, lightweight, and workable meaning that they don’t break when being put under stress. Plastics absorb energy and change their shape meaning that they don’t break apart – just look at a bulletproof glass which uses the „plastic flow” property to stop a bullet rather than breaking apart.

“This is an odd combination of properties… These materials shouldn’t be able to flow because they’re rigid solids, but some of them can. How does that happen?” says Mark Ediger, chemistry professor at University of Wisconsin-Madison.

In order to better understand this property, Ediger decided to build up a team to describe the technique that makes plastics malleable and in the same time tough. The team was led by graduate student Hau-Nan Lee, and they put common plastics under physical stress and they also increased the motion of the plastics molecules.

Ediger and his team noticed that the molecular rearrangements are 1,000 times faster when the material is not put under stress, but plastics can adapt to various conditions meaning that they don’t break on the spot.

Plastics or polymer glasses as chemists like to call them, are just the opposite of crystal because there the molecules are perfectly arranged in a pattern, while in a glass the molecules are jumbled up which makes plastics less stable than crystal, but in a strange way gives plastics the ability to not break apart when put under stress.

“Polymer glasses are used in many, many different applications. One of the reasons polymer glasses are used is that they don’t break when you drop them or fly into a bird at 600 miles per hour,” said Ediger.

The sad part comes when plastics are put under various conditions like temperature, pressure, or humidity. Even so, aircraft engineers are looking to integrate polymer glass into next-gen airplane because they are lighter than metal. Also, it seems like plastics will also be used more in next-gen electronics if they manage to overcome their flaws.

“How is it going to respond 20 years from now when it gets twisted, or stretched, or compressed? Is it going to respond by absorbing that energy and staying intact, or is it going to respond by breaking bonds and flying apart into pieces?” are only a few of Ediger’s uncertainties.

The team of researchers from the University of Wisconsin-Madison tested a plastic material called polymethylmethacrylate. This material is most commonly known as Plexiglas, or acrylic, and the reseachers noticed that a pulling force has an incredible effect on it, making the molecules to rearrange within 50 seconds.

“When you pull on it, you increase the mobility in the material. The act of pulling on it actually transforms the glass into a liquid that can then flow. Then when you stop pulling on it, it transforms back to a glass,” said Ediger.

The research is far from being completed, however, the team from UW-Madison already made some important discoveries. Hopefully, Ediger and his team will manage to learn more in the near future.
“When you pull on it, you increase the mobility in the material. The act of pulling on it actually transforms the glass into a liquid that can then flow. Then when you stop pulling on it, it transforms back to a glass,” Ediger concluded.