14 DAY TRIAL // Plastics have been around, in one form or another, for about a century now. Nowadays, they are so much a part of life and material culture that people generally take them for granted. Of course, there's been the recent unfortunate event related to its toxicity (which has been somewhat resolved) and there's a long issue related to the fact that it's not among the most biodegradable materials (but that's more of a human cleanness issue). But have you ever wondered why it doesn't break when it is bended?
Mark Ediger, a chemistry professor from the University of Wisconsin-Madison, explains that this feature, dubbed "plastic flow," is due to their ability to quickly alter their internal structuring and absorb the energy generated during the bending process instead of breaking because of not being able to cope with the new amount of energy. Similarly, bulletproof glass "flows" around bullets without breaking, unlike regular glass.
"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," shares Ediger, quoted by Eurekalert. Basically, a force that acts by altering the shape of a plastic item causes an uber-fast inner rearrangement of the material's molecules, actually 1,000 times faster than the regular rearranging process which happens when no exterior force acts on it.
"When you pull on it, you increase the mobility in the material," shared Ediger. "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." This is why many major industries, such as airplane manufacturing, have decided to include this material more into their products. The Boeing 787 airplane model, for instance, is about 50% made of plastic, comparing to the 10% of the 777 version.