If you’re reading this, it’s safe to assume you are familiar with polycarbonate. It’s the Michael Jordan of plastics. It’s easy to form, economical, transparent, and has great impact resistance--an all around great material. This is the stuff they use to make bullet proof--excuse me--bullet resistant glass. This plastic just doesn’t break. You can bend it, form it, shoot it, and more...it is not breaking.
What if I told you there were stronger plastics? While it’s great, polycarbonate isn’t the end all be all of strong plastics. In fact, there’s a whole category of plastics known as high performance plastics that have properties you wouldn’t even consider.
One such plastic is polysulfone (PSU). You can think of it as polycarbonate’s big brother. It’s transparent, fire retardant, and tough...really tough. Let’s dive a little deeper and see what makes this plastic truly special.
WHAT IT IS
First, we have to point out that polysulfone refers to a specific plastic and the family of high performance plastics to which it belongs. If you remember way back in elementary school your teacher told you a square is a rectangle, but a rectangle isn’t a square. Same thing.
Three types of polysulfones are commonly used: polysulfone (PSU), polyethersulfone (PES), and polyphenylene sulfone (PPSU). They’re typically used in applications where components are exposed to extreme conditions like extreme heat or corrosive chemicals.
Being able to stand up to harsh conditions makes PSU a great alternative to polycarbonate. It has great heat resistance and can still be extruded, molded, and thermoformed. It’s also very resistant to corrosive chemicals, which makes it an ideal material for medical applications in which it needs to be repeatedly sterilized. Although PSU is a thermoplastic, the melting temperature is so high, it’s considered fire retardant. All these super characteristics make it perfect for the medical, food, and automotive industries.
WHAT IT'S USED FOR
In the automotive industry, polysulfones are used for components that are exposed to solvents and/or high heat. Battery caps, oil pumps, and carburetor parts can be made from polysulfones. As advancements in technology continue, we may see the list of polysulfone components increase.
PSUs are also used for food containers and reusable trays. Storage containers often go from the extreme cold of a freezer directly to the high heat of an oven. The toughness of PSUs can handle that transition with no problems.
Medical applications require the same toughness. PSUs are often used for reusable trays & tray covers for medical instruments as well as components for certain devices. These things need to be sterilized frequently. PSUs can handle that repeated sterilization many times over before even beginning to show signs of degradation.
BUT IT AIN'T CHEAP
So, why aren’t PSUs everywhere? Well, it comes down to cost. The cost of materials and the cost of forming just don’t make PSUs the logical choice. The high melt temperature means that PSUs can’t be as easily formed as something like acrylic or polycarbonate. The average application also just doesn’t need the high performance characteristics that PSUs bring to the table.
High performance plastics like PSUs are fascinating. Materials that are stronger than polycarbonate and that possess comparable impact resistance is impressive. True, most projects and productions won’t need that level of functionality, but it’s good to know it’s out there.