If you’re shopping for a smartphone case, your choices in the material are often silicone, polycarbonate, hard plastics, and Thermoplastic Polyurethane (TPU). If you’re wondering what TPU is, we’re going to (figuratively) break it down.
What’s a Thermoplastic?
Plastic, as you probably know, is a (usually) synthetic material made from synthetic polymers. Polymers are substances made up of monomers. Monomer molecules form long chains with their neighbors, creating huge macromolecules.
Plasticity is the property that gives plastics their name. To be plastic simply means that a solid material can be permanently deformed. Plastics can be reshaped by molding, extruding, or applying pressure.
Thermoplastics get their name from how they react to heat. Thermoplastics become plastic at certain temperatures, which is when they are shaped as needed. When they cool down, their new shape becomes permanent until they are heated up again.
The temperatures needed to make thermoplastics pliable are much higher than, for example, your phone will ever be subjected to. So there’s little chance that a thermoplastic product will lose its shape during normal use.
Fused Deposition Modelling 3D printers, which is currently the most common 3D printer on the market, use thermoplastics. A filament of the plastic is fed through an extruder and the printer creates its product in layers that rapidly cool and solidify.
What About Polyurethane?
Polyurethane (PU) refers to a class of organic polymers that are joined by urethane links. “Organic” in this case refers to organic chemistry, which centers around carbon compounds. Carbon is the basis for life as we know it, hence the name.
One of the things that make polyurethane special is that it’s not a specific chemical compound. Polyurethane can be made from a number of different monomers. This is why it’s a “class” of polymers.
Read more: What Is Thermoplastic Polyurethane (TPU)?