Everything You Need To Know About Acrylic (PMMA)

Why and How is Acrylic (PMMA) Used?

It is a transparent thermoplastic homopolymer usually sold under the brand name “plexiglass.” Similar to polycarbonate, the material can be used as a safer alternative to glass in situations where impact resistance is essential but PC’s high impact strength is unnecessary. The Rohm and Haas Company started making it in 1928 and released it to the public five years later. It is widely regarded as one of the market’s cleanest polymers. Submarine periscopes and aircraft windows, turrets, and canopies were among its earliest uses during World War II. When it comes to eye injuries, airmen who were hit by shattered acrylic fared substantially better than those who were hit by shattered glass.

Modern and traditional uses of acrylic take advantage of the material’s inherent transparency and the impact resilience of some varieties. Lenses, acrylic nails, paint, security barriers, medical gadgets, LCD panels, and furniture are all common applications. Since it is so transparent, it is frequently used as display case windows, aquariums, and other enclosures.

The raw material permits the internal transmission of light at approximately the same capacity as glass, making it a superb substitute, even though it is made commercially available in a variety of hues (sometimes translucent and perhaps not). It is comparable to polycarbonate in almost every way. Polycarbonate often has greater impact strength, while acrylic does not contain the possibly dangerous ingredient bisphenol-A (BPA).

Acrylic is accessible and cheap. When the need for a strong material is not paramount, this is a viable alternative to polycarbonate. When you want the scratch resistance of acrylic but the impact strength of polycarbonate (PC), you can laminate the two together. Bulletproof “glass” is manufactured in this fashion. While the PC acts as a bulletproof barrier, the acrylic exterior protects against scratches.

In What Ways Does Acrylic (Pmma) Differ From Other Materials?

Knowing its primary use, we can move on to analyzing acrylic’s most salient characteristics. The term “thermoplastic” (as opposed to “thermoset”) describes the way in which PMMA reacts to heat. When heated over their melting point (in the instance of acrylic, 160 degrees Celsius), thermoplastics take the form of a liquid. Thermoplastics’ most appealing feature is their durability in the face of repeated melting, cooling, and reheating. Thermoplastics like acrylic melt rather than burn, making them suitable for injection molding and subsequent recycling.

Thermoset plastics, on the other hand, can only be heated once (during the injection molding process, normally). Thermoset materials undergo irreversible chemical changes at the first heating, causing them to set (much like a 2-part epoxy). A thermoset material would melt if you tried to reheat it to a high temperature. Thermosets aren’t great candidates for recycling because of this quality.

How Come We Always Employ Acrylic?

When low weight and high transparency are prioritized over strong impact resistance, acrylic is an excellent plastic choice. Acrylic, unlike other transparent polymers, is highly resistant to scratches. It’s cheaper than polycarbonate and easier on the wallet than glass for uses where strength isn’t absolutely necessary. Since the substance vaporizes when hit by the concentrated laser energy, it may be sliced into incredibly small shapes utilizing laser cutting technology. Acrylic is rarely used because of the material’s brittle failure and comparatively low strength. We prefer to use PC and PETG instead. Plastics made of PC and PETG are not as transparent as acrylic, but they are considered “clear enough” for most purposes. Acrylic will be used if the need for perfect transparency is critical. Acrylic has been CNC machined, and we have also molded it by hand. Parts are typically polished after machining to remove machine markings and restore optical clarity. Here are a few instances in particular:

In The Capacity of A Lens (learn more about our magnifying glass experiment).

as an alternative to traditional glass jewelry (for example, we developed a line of acrylic cuff bracelets as part of a project). Our forming machine involved cutting the flat shapes, then heating and bending the bracelets.

Exhibit goods (for instance, we built a life-size replica of a crystal iPhone case by hand). We needed an easy-to-machine material because of the size, which was around a foot by two feet. PC would have been too expensive, and the clarity and polish of the parts were more crucial for this purpose.

How Many Acrylic (PMMA) Varieties Are There?

The invention of acrylic acid in 1843 was a pivotal discovery that paved the way for the development of acrylic plastic. German chemist Otto Rohm trademarked the word “plexiglass” in 1933, over a century after the invention of the material. Numerous companies produce it now, often using their own methods of manufacture and recipes for the final product. Some well-known brand names are Lucite® by DuPont and Plexiglas® by ELF Atochem.

How Is Acrylic Fabricated?

Distilling hydrocarbon fuels into lighter groupings called “fractions” yields some of the catalysts needed to interact with other catalysts to form plastics (usually via polymerization), and this is where acrylic (and other polymers) get their start.

Prototyping Using Acrylic On Cnc Routers And 3d Printers:

Sheet stock and round stock of acrylic are readily available, making it a viable material for subtractive machining on a mill or lathe. Many different hues are typically offered. There are additional fluorescent color options for acrylic sheets. The term “edge lit” is sometimes used to describe these. When viewed head-on, the sheet’s color is muted, but when viewed from the side, the color appears bright and almost lit from within, even though no light is present.

Clear stock components typically require finish sanding and/or polishing after machining to remove tool markings and restore the material’s original transparency. Heating acrylic sheets allows them to be molded into almost any form with relative ease. Heating the point of the bend with a wire heater allows for easy bending. Also, by heating the entire sheet, you may drape it or mold it into any shape you like. When assembling a multi-piece acrylic part, solvents are typically used to melt the surfaces together, creating a nearly invisible seam.

Can You Eat Acrylic?

Advantages of acrylic include its resistance to hydrolysis (degradation due to material interaction with water) and the absence of bisphenol A (BPA) in its composition or release during hydrolysis. Polycarbonate, a similar plastic, includes bisphenol A, a chemical whose toxicity has been debated. However, acrylic does not have this problem. Government-funded research consistently found that BPA poses a high danger to human health, while industry-funded studies often found reduced or no hazards. While there is conflicting evidence on the harmful effects of bisphenol A (BPA), particular forms of polycarbonate have been linked to BPA leakage. Because of this, “BPA-free” polycarbonate products (often shown on consumer products like canning jars) have emerged in the market. Another “BPA-Free” material that is safe to use as a PC replacement is acrylic. However, the vapors produced by 3D printing with acrylic or the molten material used in injection molding should not be breathed in and the manufacturing process should take place in a well-ventilated area.  

Video 01: What is Acrylic Plastic? | Is it the same as Polycarbonate? | Acrylic Uses