Which Plastic Should You Choose?
At Cut My Plastic we offer both acrylic and polycarbonate plastics for a wide array of applications. One question our customers ask a lot is how are the two types of plastic different, and is one clearly “better” than the other? Well, we’ll answer the first part of that question below but we can answer the 2nd part now. One is not intrinsically “better” than the other. Which one you choose will depend on a variety of factors including budget and how you intend to employ it. One may be better than the other for the particular purpose you have in mind but they are both high-quality, extremely versatile materials.
How Acrylic and Polycarbonate Differ
First off both acrylic and polycarbonate can be used as a substitute for glass where use of glass is either prohibitively expensive or practically unfeasible. Either can be used as a substitute for glass windows or to add colour or diffusion to a lighting scheme. Here are 2 dozen other uses for acrylic and/or polycarbonate sheets:
- Picture Framing
- Display Cases
- Public Bus Shelters
- Motorcycle Windshields
- Table Tops
- Commercial Signs
- Storm Windows
- Photography Light Boxes
- Sound Barriers
- Water Tanks
- Medical Face Masks
- Museum Displays
- Food Containers
- Point of Purchase Displays
- Food Shields
- Instrument Covers
- Speaker Boxes
- Brochure Holders
- Wind Blocks for Balconies
- Optical Lenses
Plastic sheets typically weigh just a fraction of what an equal size glass sheet would weigh and cost less. Depending on the thickness they also display varying degrees of impact resistance and are generally useful in temperatures as high as 240° F. Thus, in situations where the glass may present a safety issue (such as pre-schools and medical environments etc) an acrylic or polycarbonate sheet may be both a practical as well as financially responsible alternative.
Differences in Production
- Acrylic plastic is produced using monomer methyl methacrylate, typically in syrup or powder form. It is then formed into sheets (or custom shapes) using a polymerizing catalyst: peroxide being a common choice. The resulting acrylic sheet is often referred to as “plexiglass”.
- Polycarbonate is created by the reaction between Phosgene and Bisphenol A. The hot plastic mix that results is then injected into forms or extruded to create pipes and bars.
- Acrylic is many times more impact resistant than glass. At the same time it weighs less than half what similar sized sheets of glass would weigh. Acrylic is slightly more rigid than polycarbonate which makes it great for some applications like windshields and less so for other applications where a degree flexibility is preferred such as medical face shields.
- Polycarbonate is even more impact resistant than glass - up to 250 times more impact resistant - making it an ideal alternative when safety considerations are at the fore. In fact polycarbonate is often used in bullet-proofing. At the same time, like acrylic, polycarbonate is much lighter than glass. Of the two, polycarbonates are slightly more resistant to damage by solvents meaning ammonia may be used in some circumstances to clean polycarbonate whereas you would not want to use ammonia to clean acrylic.
Clarity and Light Transmission
Acrylic will actually allow more light to pass through than glass while polycarbonate is not quite as efficient at letting light through. You can, if you so desire, polish an acrylic sheet to restore its clarity should it become muddied. While you cannot polish polycarbonate.
Working Acrylic and Polycarbonate Sheets
Plastic sheets wouldn’t be much use if you couldn’t work them to adhere to your desired application so thankfully both acrylic and polycarbonate are fairly easy to work with and don’t represent the type of injury threat glass does. There are, however, some basic rules you’ll need to adhere to when working with these materials in order to ensure you get the desired result.
- As a general rule acrylic, because of the fact that it’s slightly more rigid than polycarbonate, is easier to cut using conventional tools like power saws or even routers. Still, you need to make sure the material is being held firmly before you apply a saw blade to it in order to avoid damage to the area around the cut.
- Polycarbonate, because it is slightly more flexible, will resist the initial application of the saw blade. You need to be patient when applying the initial force and don’t try to rush the process. Once the material has accepted the blade cutting will typically proceed in a smooth fashion.
Drilling is another activity where the relative rigidity of the material will play a role.
- When drilling acrylic you need to be particularly careful near the edge of the sheet where cracks can appear if you use the wrong drill bit. Therefore you should be sure to use a drill bit designed specifically for acrylic. They’re not expensive and using them will save you a lot of time, frustration and money.
- Polycarbonate is much more forgiving when it comes to drilling holes. Even when working close to the edge of a polycarbonate sheet you’re not likely to create cracks with the drill bit.
Both acrylic and polycarbonate are fairly heat sensitive but only in relation to extreme temperatures. Acrylic and handle temps up to 190° F while polycarbonates are heat resistant up to 240° F. When it comes to manipulating the different materials through heat bending acrylic will be more malleable due to its lower level of heat resistance. If you’ll be needing to heat bend your plastic sheet for whatever reason you may want to consider acrylic over polycarbonate for this reason.
On occasion it’s necessary to glue 2 or more pieces of plastic together for a certain application. In such cases be aware that acrylic typically creates a cleaner glued joint than polycarbonate. If the glued joint will not be visible this may not be a problem. But if, for instance, you are using plastic to create a display case where all sides are exposed acrylic may be your wiser choice.
Acrylic and polycarbonate sheets are both easy to clean. The only thing you need to keep in mind is that they’ll both typically scratch easier than glass and so you should be sure to use a microfibre or soft, clean cotton cloth when cleaning either surface.
- Acrylic is not as resistant to chemicals as polycarbonate. Therefore you’ll need to use either mild soapy water or specific commercial cleaners designed to be used on acrylic. Be sure you never attempt to clean acrylic with solvents, or solvent based cleaners.
- Polycarbonate is a chemically tougher material and you don’t need to be quite so picky about the cleaner you use on it. Just remember though to always use the microfibre or cotton cloth mentioned above. You can use ammonia on polycarbonate but you should never use anything stronger than that. And definitely no solvents.
Both materials are weather resistant though keep in mind before exposing them to the elements that, as we mentioned earlier, they’ll scratch easier than glass. Both materials are known to expand and contract as temperatures change although neither will suffer permanent damage from this process. If used indoors in a controlled environment the practical life expectancy of both products is formidable. Also, if you need to build display cases keep in mind that acrylic won’t yellow over time.
In general polycarbonate tends to be about 1/3 more expensive than acrylic. Although that depends in large part on whether you’re purchasing simple sheets or something more elaborate.
Health and Safety Considerations
In environments where open flames may be present acrylic should probably be avoided. Acrylic can actually burn if exposed to a direct flame and it’s relatively low heat resistance threshold of 190° F means that even if it doesn’t burn it may lose integrity if a flame gets too close. Polycarbonate by comparison is slightly more heat resistant and has a smaller likelihood of actually catching fire. Even if it does, any flame may extinguish itself. Again though, as with acrylic, the heat resistance threshold is not great (240° F) so even if the polycarbonate does not catch fire it may lose structural integrity if a heat source gets too close. There is also some evidence (though nothing scientifically conclusive) that polycarbonate may be unsafe to use for food storage. Just to be on the safe side you may want to opt for acrylic in such cases.
Acrylic and polycarbonate are the kind of materials that make the modern world go round. Versatile, lightweight, tough, malleable and affordable they’re the common sense alternative to brittle, heavy and expensive glass. Whether acrylic or polycarbonate will be right for you depends on the application you have in mind. Keep the above facts handy when deciding which material best suits your needs so that you can make an informed decision. And contact Cut My Plastic on 01903 389024 should you have any questions.