Kersasp: Hello there! Wasn’t that you in the paper’s city section? The story about the attempted jewellery store robbery?
California Valley Girl: Yeah, that’s me and I’m a lucky gal! I wuz standing on the inside of there shop window when some robber smashed it with an iron rod and it broke. Luckily the glass didn’t, like, shatter into sharp flying pieces Ð it broke into big slabs that just fell down. And the edges weren’t even sharp!
K: AhaÑ then that wasn’t glass; that was acrylic. Lucky you; smart shopkeeper!
CVG: Oh! It was? How d’ya know?
K: You just described it. Upon impact glass shatters into sharp-edged pieces. And because glass is dense, pieces can travel for a good distance. But acrylic, well, it is almost unbreakable and when it does rupture, it breaks off into large pieces Ð after all, it is a heat-formed polymer with large molecular bonds. And because it’s not dense, like glass, pieces are much lighter and so they don’t fly through the air.
CVG: I’ve heard the word ‘acrylic’ most commonly as . . . like, ya know, it’s a paint, a colouring medium. So . . .
K: Sure, to an artist the word ‘acrylic’ will have a very specific meaning. You have water colours, oil paints, acrylic colours, and so on.
CVG: How can acrylic be both Ð you say it’s a glass-like thingy so how can it also be a type of paint or colour?
K: Colours or paints comprise of pigment and a ‘carrier’ that is a suspension or emulsion. The carrier in ‘acrylic colours’ is an acrylic polymer. It brings elasticity to the emulsion; as a result it is adaptable to temperature variations and will expand and contract, and so acrylic colours do not crack. That’s the advantage of acrylic colour Ð it doesn’t crack like oil paint.
CVG: What about the advantages, then, of acrylic Ð I mean solid acrylic? And does it have any disadvantages?
K: Advantages? Like how! It is highly light transmissive, it won’t crystallize or get cloudy, it’s lightweight and it’s long lasting. That’s several good reasons that that shopkeeper chose acrylic storefront windows. Probably its only disadvantage is that it must be kept away from extreme heat else it will deform. But over and above everything I think that acrylic’s shatter-resistance is its most prized property. You know, 32 millimetre acrylic of good quality is bullet resistant, it’s ‘bullet-proof’.
CVG: I know plexiglass is bulletproof too. Are acrylic sheets better than plexiglass Ð ya know, are they clearer and harder to break?
K: Well, that depends on which acrylic sheets you’re comparing to ‘plexiglass’ Ð because Plexiglas is a brand-name for a particular company’s acrylic sheets! Just like Frigid-Air was a refrigerator brand-name that became synonymous with the word ‘refrigerator’ so too Plexiglas has become like, well, a common noun! Plexiglas is the first, original acrylic that was invented by Rohm & Haas and is still made by them.
CVG: Huh! Are there any other brand-names for acrylic?
K: Have you heard of Lucite or Perspex? Those too are well-known acrylic brands.
CVG: Oh yeah Ð my gran has a Lucite 3D picture tile! So I guess acrylic has other uses besides windows and things?
K: Lots and lots! Decorative items like those picture tiles and skylights, glasses, displays, knick-knacks, helmet visors, drinking glasses, aircraft windowsÑ
CVG: I though those aircraft windows were made of a thick plastic!
K: You’re not too far off. Acrylic is a type of ‘thermoplastic’ which a part of our daily lives. You may not have heard of polycarbonate but you’ve definitely handled it hundreds of times Ð you’ve played CDs and DVDs, right? Polycarbonate too is a thermoplastic, of which there are over 30. The common factor is that both acrylic and polycarbonate are made of polymer resins. The most endemic one is polyethylene, often misspelt and mispronounced as ‘polythene’. That’s what plastic bags are made out of.
CVG: D’ya know how acrylic made?
K: Yup. Briefly, good quality acrylic is made by a casting process. Semi-liquid acrylic under high heat is poured into wide, broad moulds. After it cools and hardens in the moulds it is removed. If needed, pieces can be cut using either a laser or a specially built circular saw. Moderate heat is used to smooth out the cut edges, and buffing cloth is used to polish them.
CVG: Gee, you’re real smart!
K: Uh, well, almost everyone says that. Welcome to the club!
CVG: Ha, ha! Tell me, how can you know when something is acrylic?
K: Well, one simple rule is that anything that’s transparent or translucent, is hard and isn’t glass, is probably acrylic.
CVG: Then how wiÑ
K: Look, enough about acrylic. Why don’t you just read my award-winning article on the subject, “Say ‘Hello’ to ‘Miss Resin-Thermoplastic’!”? Instead of acrylic, let’s talk about something else. Like, can I buy you a drink?
CVG: Sure, thanks! Red wine . . . in an acrylic glass?