1. Polymers Polymers or ’plastics’ are a relatively modern material. They were first produced in the early twentieth century; their use grew rapidly during the second half of the century, and continues to grow today. Polymers have provided alternatives to many packaging requirements previously carried out by metal, glass and boards, and have often completely replaced these materials. Thermoplastics Thermoplastics are polymers that, once heated, can be formed into a variety of interesting shapes using different forming techniques such as blow moulding, vacuum forming and injection moulding (see pages 44-46 for more on these techniques). Once the polymer has cooled down, the shape then remains permanent. The same thermoplastic can be heated, softened, shaped and cooled many times over, which means these materials are ideal for recycling. Thermoplastics are used in a wide range of graphic products, from the Styrotoam models that you make in the classroom, to the shop signage you see on the high street and the injection-moulded casings of many electrical products, such as games consoles. Polymers in electrical products Many electrical products make use of polymers to form their protective casings. Polymers have a number of advantages over metal casings: They are less expensive to produce in large quantities and thermoforming processes, such as injection moulding, can produce extremely intricate shapes They are non-conductive — they do not conduct electricity — so products are safe to handle They have excellent heat—resistant properties, which is an advantage where electronic components can become quite hot with prolonged use (just think about your games console when you have been playing a game tor a long time).

2. Polymers Acrylic Acrylic is usually cast into sheets but is also available in rods and tubes. It is self—finishing, so it does not need to be painted. Acrylic has a wide range of uses within graphic products, from making models to shop signage. When making a model, acrylic is a versatile sheet material as it can be easily cut and bent using a strip heater. Thinner sheets of acrylic can also be vacuum-formed just like polystyrene or PVC. Acrylic is available in a Wide range of colours, and has an excellent surface finish, which adds a quality feel to any model. In shop signage, a higher quality acrylic is used which must satisfy several high performance requirements. it has to be able to: Withstand extreme weather conditions, such as heat in the summer and cold in Winter. Be chemical—resistant to pollution and detergents Be durable by resisting |ong—term stresses, such as being. outdoors for prolonged periods Be easy to fabricate and to make relatively complicated shapes out of Have excellent aesthetic properties, to attract a customer’s attention and give a high-quality look for the business.

3. Polymers Styrofoam ”Styrofoam" is a polystyrene foam manufactured for the construction industry for insulating buildings. It also makes an excellent modelling material. The process of making the foam results in a material with uniformly small, closed cells, which gives it all of the properties that a modelling material should have, including: Great rigidity and high compressive strength so it cannot be bent out of shape easily Easy to cut and shape with a range of hand tools Sheets can be glued together using PVA to form larger blocks A smooth surface finish when sanded Can be painted to give a good quality finish if desired.

4. Polymers Expanded polystyrene Expanded polystyrene is used in fast—food packaging because it is: hygienic — disposable cups and plates mean germs and bacteria are simply thrown away with the rubbish instead of multiplying in a chipped coffee mug, for instance. strong, yet lightweight- protects against moisture and keeps its strength. Containers and lids close tightly and prevent any leakage of the contents. it can be moulded into a variety of structural packages which complement its excellent cushioning properties in protecting y the contents of the package. efficient- provides excellent insulation. Therefore, hot food can be kept warm for longer periods. It also means that the package does not become so hot that it cannot be held in the hand. economical- products are generally cheaper to buy than disposable paper products and much cheaper than reusable service ware (e.g. china). This is because only about five per cent of the foam package is actually plastic — the rest is simply air convenient- with today’s busy lifestyles people want food to be available instantly, and polystyrene is an economical way of serving people with their fast food. Expanded polystyrene is also used in the protective packaging of many delicate products, such as electrical products; shape—molded, it fits snugly around products which are placed inside corrugated board boxes.

5. Polymers Polymers in commercial packaging Polymers are widely used in commercial packaging because they are: lightweight and versatile strong, tough, rigid, durable, impact and water—resistant easily formed and moulded easy to print on low—cost recyclable. Polymers can be identified by a code, usually stamped onto the base of the package or printed onto the label. An internationally recognised coding system means that you can easily identify polymers and sort them for recycling. Each polymer has its own useful properties, making it suitable for use in different areas of the packaging industry. Disadvantages of polymers - Environmental concerns The main disadvantage for the widespread use of polymers centres on concerns about how sustainable they are. They are made from oil, which is a finite resource that requires a lot of energy to process, producing high levels of pollution. Manufacturing techniques for polymer-based packaging, such as blow moulding, also consume a lot of energy. Then comes the problem of disposal. Polymers are durable and degrade slowly, which is a problem for landfill sites.