Acrylic plastic is everywhere: in home improvement products, in sporting equipment, as transparent non-glass applications, in water-resistant paint and as a coating for fiber optic cabling.
Perspex fabrication processes have definitely changed the world we live in. Just take a look around you, wherever you are, and you will most probably see an item made from acrylic plastic.
But how is this amazing and versatile material made? Acrylic fabricators would describe more or less the following process – and it’s really interesting:
The raw materials
Acrylic plastic is a polymer and one of the particularities of polymers is that such materials have properties entirely different from their component parts. The basic molecule or monomer from which acrylic plastic is made is methyl methacrylate, whose chemical notation is CH₂ = CCOOCH₃ or C5H8O2. The “=” shows the double bond between the two carbon atoms in the middle. During polymerization, one leg of this double bond breaks and links up with the middle carbon atom of another methyl methacrylate molecule, thus starting a chain. The process repeats itself until the final polymer is formed.
The manufacturing process of acrylic plastic
The process of making a polymer is called polymerization. Acrylic plastic, which is later processed as acrylic sheet cut to size or other products, is formed by reacting a monomer, such as methyl methacrylate, with a catalyst. One of these catalysts is organic peroxide, which starts the reaction and keeps it going, but does not become part of the resulting polymer.
If the raw materials are toxic or not particularly friendly (acetone, methanol, hydrogen cyanide and sulphuric acid), the end product is totally harmless.
What types of acrylic plastic are there and how they are made
Acrylic plastic is available in three forms: flat sheets, elongated shapes (rods and tubes), and molding powder. The latter is sometimes obtained through a process known as suspension polymerization in which the reaction takes place between small monomer droplets suspended in a solution of water and catalyst. This result is represented by grains of polymer with precisely controlled molecular weight suitable for molding or extrusion.
Acrylic plastic sheets are obtained through a process called bulk polymerization and can be later transformed into acrylic sheet cut to size. In this case, the monomer and the catalyst are poured into a mold where the reaction takes place. Two methods of bulk polymerization can be used: batch cell or continuous. Batch cell is the most common due to its simplicity and ability to produce acrylic sheets with dimensions from 0.06 to 6.0 inches (0.16-15 cm) thick and from 3 feet (0.9 m) up to several hundred feet wide. The batch cell method can also be used to form rods and tubes. The continuous method is quicker and produces sheets of thinner thicknesses and smaller widths than those produced by the batch cell method.
Quality control and safety
Although the final product is safe, the raw materials and chemical substances used to manufacture acrylic plastic are potentially dangerous. Clients who buy Perspex sheets are lately interested in products manufactured under controlled environmental conditions to prevent contamination of the material or unsafe chemical reactions. Controlling the initial temperatures of the monomer and catalyst before being introduced into the mold is important in order to ensure the heating and cooling cycles required to manufacture acrylic plastic safely.
The properties of acrylic plastic
Acrylic plastic, also known as poly(methyl methacrylate), is part of a group of materials called engineering plastics. The main properties of this versatile and affordable material include:
Clarity
Acrylic plastic has glass-like properties and is even more transparent than glass. Believe it or not, acrylic transmits more light than glass. Acrylic can transmit up to 92% of visible light, while glass transmits between 80 and 90 percent.
Lightweight
One of the advantages of using acrylic plastic instead of glass is weighing 50% less than glass while also being more durable. This property makes transport and installation easier and less expensive.
Good impact resistance
One of the first uses of acrylic plastic was during WW2 for plane windshields as this type of material does not break easily like glass. Even if acrylic does break, it will produce large, dull pieces which are way less dangerous.
Easy to process and shape
Acrylic is a thermoplastic, so heat makes it soft and moldable into different shapes and sizes. As it cools and holds a formed shape, acrylic can be processed in a machine; manufacturing processes are inexpensive and versatile.Looking to buy Perspex sheets or other plastic products? Plastic Online Australia provides a variety of materials cut to size – discover our range of products today!
