1.3 NON-METALS POLYMERS, PLASTIC MATERIALS In this unit we are going to examine the properties and applications of non-metallic materials which have become widely used in every sector of our life. The term plastic The term originated from the Greek word , meaning fit for . It refers to the material’s malleability or plasticity during manufacturing, which allows it to be cast, pressed, or into a variety of shapes. plastic plastikos moulding 1 extruded 1 #####DO What difference is there between the two terms malleability and plasticity? See unit 1.1. 1 MORE Before the invention of plastic, the only substances that could be moulded were and glass. Hardened clay and glass were used for storage, but they were very heavy and brittle. 1 clay What is plastic? is any synthetic or semi-synthetic organic polymer . A is a chemical compound with very small molecules (monomers) bonded together in long repeating chains. Polymers can be both: Plastic 2 polymer , such as cellulose and , or natural rubber substances, which are generally derived from oil and are usually referred to as “plastic” materials. synthetic Any polymer used to make plastic is almost always mixed with additives (colourants, stabilisers, fillers, and reinforcement) that affect its properties. MORE The world’s first fully synthetic plastic was Bakelite, invented in New York in 1907, by Leo Baekeland, who used the term “plastics” for the first time. 2 Features and applications Plastics have a lot of different applications: from optical components to telecommunication equipment, from food storage to adhesives, from architectural elements to car parts, clothing, ski boots and safety . Moreover, plastics are perfect insulators as they do not allow electricity or heat to flow through them and this high resistance to the flow of electric current makes them well-suited to electrical applications. helmets Types of plastics According to their chemical and structural plastics are usually classified as: bonds, , which or melt when heated and when cooled: in particular, they can reheating processes in order to be reshaped into a new form; Thermoplastics soften harden undergo , which cannot undergo processes and become permanently hard and rigid when heated. Thermosettings reheating Elastomers There exist some special polymers called which are very elastic because the intermolecular forces between the polymer chains are rather weak. They can be both natural and synthetic and their main quality is that of returning to their original shape after deformation. Most of them are synthetic, derived from sub-products of petroleum and natural gas. They are the basic material for any rubber products and adhesives, and their high resilience, elasticity and toughness make them fundamental for the production of , for example. elastomers tyres
