What are Plastics?
PLASTIC: noun > a synthetic material made from organic polymers, that can be moulded into shape whiles soft and then set into a rigid or slightly elastic form. Origin – Greek plastikos , from plassein “ to mould”.
A true plastics material is one which remains permanently deformed when it is stressed, thus modeling clay is a ‘plastic’. The application of the generic term “plastics” to the products in our industry is therefore not truly correct. Through common usage, the term “plastics” is now applied to products which as some stage of their processing are capable of flow to assume a desired shape. This shape is retained by the material after the shaping operation is completed.
Organic materials are defined as compounds which contain a high percentage of the element carbon in their make-up.
Plastics are rapidly penetrating into many industries and where advantage is taken of their unique properties, the rate of growth is very fast indeed. The more conservative approach is to use plastics as substitutes for conventional products. The more realistic approach is to design for plastics, with full knowledge of their properties and their processing characteristics, to create new concepts and at the same time achieve more effective use of materials.
Plastics technology is pushing ahead as productivity increases and long term performance data related to particular end uses is being compiled to assist the designer. Much present day research is being directed towards the engineering applications of plastics, where plastics form the working components. The progress which has been made to date is significant, and with new polymers and new technology, coupled with correct design and application, an even greater rate of progress will be achieved.
It is a definite advantage that plastics materials are man-made, for through the techniques of modern research and the production technology of raw material manufacturers, polymers are now being tailor-made with specific fields of end application in view. Recognise the development which is occurring within the plastics industry; learn to design with plastics study the properties of plastics so that you can select the correct material for each application.
When compared to other materials, plastics have unique properties, causing them to contribute greatly to our everyday life. Plastics, properly applied, will perform functions at a cost other materials cannot match. Many natural plastics exist, such as shellac, rubber, asphalt and cellulose. However, it is man’s ability to synthetically create a broad range of materials demonstrating various useful properties that has further enhanced our lives. Most plastics are different from other materials such as glass, steel and aluminium because they can creep or change shape when stressed. Ignoring this fact is the greatest cause of failures in designs using plastics.
There are three major markets of plastics materials: mechanical and engineering plastics; sign and display and architecture.
The Engineering Plastics market segment covers plastic materials that are primarily used in wear applications. Typical examples include applications where external loads are applied to the plastic materials such as bearings, bushings, wear strips, liners, sheaves and gears. Plastic materials generally used in this market segment are semi-crystalline thermoplastics.
The Sign and Display market is evident all around us. These materials are used to sell products, advertise companies and their display merchandise. The aim is to achieve maximum impact on consumers’ hearts and minds. Different trends are a constant, always changing challenge for retailers, designers and advertisers. Examples include store fixtures, tradeshow displays and all kinds of signage. Typical plastics used in this market include acrylic, ABS, CAB, foam boards, nylon, polycarbonate, polyesters, polyethylenes, polystyrene and PVC.
Architecture is the science of designing and erecting buildings (commercial, residential and industrial), which furnishes a practical use along with aesthetic solutions. Plastics continue to make significant inroads into this market due to increasing cost competiveness with traditional materials (wood and metal) and their properties of interest to architects; durability, colour range, transparency, light weight, ability to withstand the elements, high strength-to-weight ratio, ease of cleaning and corrosion resistance etc. Plastics normally seen in the architecture market are acrylic, polycarbonate, PVC, PVC foam, ACM (aluminium composite material) and CPVC.