When a brand name becomes synonymous with a material, we have a habit of attaching that label to the product. In essence, we let the marketing machinery rule our vocabulary. Plexiglass is one such material, a transparent thermoplastic that has as many names as it has desirable properties. It’s known as perspex in the United Kingdom, lucite in the fashion industry, and acrylic in light industry, but its proper chemical label is polymethyl methacrylate. Designed to replace glass, the clear plastic incorporates a number of handy properties, physical and mechanical characteristics that go beyond transparency.
The label is short, succinct, a perfect marketing term for a translucent plastic, one that has glass-like aspirations. After all, acrylic is every bit as clear as glass, but it’s not nearly as stress-intolerant. The thermoplastic can bend and be shaped into usable products, for instance. That versatile form first came about in the mid-twentieth century, with polymerization technology throwing two chemical compounds together to give birth to this celebrated translucent product. The first chemical, methanol, is a liquid we commonly refer to as alcohol. It mixes with the second compound, methacrylic acid, an organic acid with an acrid odour. Once these two substances react, they create a coalescing chemical soup, the see-through star of this article.
Make no mistake, this is a thermoplastic, but it’s one that takes the place of glass in hundreds of applications. The transparent plastic actually transmits light more efficiently than glass, and it does so without filtering colour or blurring what’s on the other side. The featherweight product also incorporates a superior thermal conductivity factor, so it doesn’t suffer from the films of condensation that obscure mineral glass. As for applications, we find plexiglass used in aquariums, car lighting, skylights, and windscreens. As with any other tailored plastic, special additives can imbue the material with many other customised attributes, including UV protection and enhanced flexibility
Of course, what with the benefits of the toughened plastic pulling way ahead, we’re tempted to call this clear plastic the uncontested winner, but there are a few flaws in the form. The synthetic glass can scratch, plus it doesn’t always react well to chemical cleaners or high temperatures. Fortunately, modern chemical additives and advanced formulations minimise these issues, which means the thermoplastic, extruded or manufactured in sheets, is absolutely worthy of consideration when a synthetic glass substitute is needed.