There are many requirements in our lives for clear plastics, from packaging that allows us to see the products we want, to submarine windows that restrain thousands of tons of pressure, yet allow us to see life beneath the waves.
The plastics industry has over the years developed a number of products that suit the sometimes harsh environments mother nature often throws at us, the most common two being Polycarbonate and Acrylic.
So, what are the differences between these two seemingly similar transparent polymers?
Well, characteristically Acrylic is less likely to succumb to scratches than Polycarbonate, but on the flipside- Acrylic will stay clear after years under sunlight whereas Polycarbonate will yellow.
Of course it’s not as simple as that, so lets look a little more closely at the technical differences.
Even the thinnest section of either polymer is stronger than glass, between 10 and 20 times stronger for Acrylic. Polycarbonate, known for its use in bulletproof windows offers up to 250 times the impact resistance than that of glass.
They are both very strong, but Polycarbonate is stronger by an order of magnitude.
The ability to transfer light under varying conditions is a pre-requisite for a clear plastic and both Acrylic and Polycarbonate are regularly used for glazing.
The amount of light that passes through both polymers has been extensively tested with Acrylic allowing 92% of light to pass and Polycarbonate coming just a touch lower at 88%.
However, and as mentioned above, Polycarbonate will yellow after any reasonable length of time under UV, whereas Acrylic will not. Plus, Acrylic can be polished back to clarity if any discolouration does occur.
Polycarbonate doesn’t take to polishing at all well and the yellowing is not simply on the surface, it is throughout the polymer that makes up the sheet.
Any engineer or tradesmen will tell you that the workability of a product is key to it’s use in industry and the building trade. Both polymers are capable of being cut, drilled, bent and formed to any required specification, however there are differences.
Acrylic is more likely to chip and crack when being drilled or cut than Polycarbonate, much more so in-fact. Polycarbonate is readily bendable under normal working temperatures whereas Acrylic requires some level of heating to avoid the sheet cracking or shattering.
Polycarbonate is also highly resistant to industrial and petrochemicals such as petrol and acid.
Both types of polymer can be readily glued using off the shelf products. Both will when installed correctly provide a watertight seal that should last many years.
Soap and water and a cotton cloth is all that’s required for both types of plastic. Neither is particularly difficult to keep clean, however it must be remembered that Polycarbonate sheet will yellow over the years, and this cannot be cleaned.
Acrylic is almost half the cost of Polycarbonate.
Common Uses for Acrylic
Motorcycle and motor racing helmet visors.
Submarine and diving bell windows.
Riot vehicle protection
Windows and Glazing
Common Uses for Polycarbonate
Compact discs and DVD’s
Windows and glazing