Plastic Plastics are derived from organic products. The materials used in the production of plastics are natural products such as cellulose, coal, and natural gas, salt and, of course, crude oil. Crude oil is a complex mixture of thousands of compounds. To become useful, it must be processed. How plastic is made The production of plastic begins with a distillation process in an oil refinery The distillation process involves the separation of heavy crude oil into lighter groups called fractions. Each fraction is a mixture of hydrocarbon chains (chemical compounds made up of carbon and hydrogen), which differ in terms of the size and structure of their molecules. One of these fractions, naphtha, is the crucial element for the production of plastics.
The two major processes used to produce plastics are called polymerisation and polycondensation, and they both require specific catalysts. In a polymerisation reactor, monomers like ethylene and propylene are linked together to form long polymers chains. Each polymer has its own properties, structure and size depending on the various types of basic monomers used. There are many different types of plastics, and they can be grouped into two main polymer families: Thermoplastics (which soften on heating and then harden again on cooling) Thermosets (which never soften when they have been moulded).
History of plastics The natural breakthrough for the first semi- synthetic plastic’s material cellulose nitrate occurred in the late 1850s and involved the modification of cellulose fibres with nitric acid. Cellulose nitrate had many false starts and financial failures following its invention by a Briton, Alexander Parkes, who exhibited it as the world’s first plastic in 1862. First known as Parkesine, then Xylonite, it began to find success in the production of objects such as ornaments, knife handles, boxes and more flexible products such as cuffs and collars. 1907 – The first man made plastics Bakelite, a condensation product of phenol and formaldehyde, was invented by Leo Baekeland, a Belgian-born chemist. It was the first truly synthetic plastic to be patented. Because of its excellent electrical insulating properties, it was initially used to make electrical insulators in cars and industrial products. Later it found its way into consumer products such as telephones, radio cabinets, ashtrays and cameras. 1912
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A German chemist, Fritz Klatte, discovered the basic principles for the industrial production of polyvinyl chloride, PVC. Klatte also discovered vinyl acetate and obtained patent for its preparation from acetylene gas. Its corresponding polymer, polyvinyl acetate PVA is used in latex prints and is reacted with aldehydes to make coatings and films, in particular polyvinyl butyral, widely used in laminated safety glass. 1921 The first injection moulding machine was designed and the following year the first spectacles were moulded in cellulose acetate. 1930 Polysterene was first produced commercially when an economic process pro cess to produce styrene monomer was developed and a method was found to prevent premature polymerization of the monomer during storage and shipping. 1940- The first totally man-made fibre Nylon had been discovered at the end of the 1920s but was not put to great use until the 1940s. Capable of being spun into long filaments which could be woven or knitted, the new plastic was used to do anything from parachutes to ladies stockings.
General condensation polymerization reaction for nylon 1950- A first for the car industry 1956 saw the major use of plastics in car body design d esign when the roof of a Citroen DS was made from unsaturated polyester reinforced with fibre glass. This combination became a popular choice thereafter in the production of body parts for cars and boats. 1960-Home Decor The first domestic items made from moulded polypropylene were developed from 1963 onwards- including combs, lemon squeezers and bottle stoppers. 1973 The first oil crisis saw crude oil shortages and a doubling of the price. For the first time, attention became focused on the finite nature of oil supplies. With increasing recognition of their contribution to reducing oil for energy and transport, production of plastics accelerated. 1980 Laminates saw a revival in the world of interior design. But unlike the decorative laminates of the 1960s, the new breed was at the upper market. 2
1992 Metallocene catalysts initiated a new era in the production of polyolefins such as polyethylene and polypropylene. They enable producers to precisely define the polymer structure and hence the physical properties of these plastics. 2001 Plastics have enabled mankind to live in the most challenging environment-space. As the International Space Station began to take shape, the contribution of plastics could be seen everywhere. Plastics were essential in the design of many key components: structural elements, insulation, life support systems, space-unit fabric, food packaging, guidance and communication systems etc. The electricity supply for the station comes from solar panels made from plastic.
Plastics materials Everywhere you look you will find plastics. We use plastic products to help make our lives cleaner, easier, safer and more enjoyable. You will find plastics in the clothes we wear, the houses we live in, and the cars we travel in. The toys we play with, the televisions we watch, the computers we use and the CDs we listen to contain plastics. Even the toothbrush you use every day contains plastics. Plastics applications The relatively low density of most plastic materials mater ials means the end products are lightweight. They also have excellent thermal and electrical insulation properties. However, some can even be made as conductors of electricity when required. They are corrosion resistant to many substances which attack other materials, and some are transparent, making optical devices possible. They are also easy to mould into complex shapes and forms, allowing integration of different materials and functions. And in the event that the physical properties of a given plastic do not quite meet the specified requirements, the property balance can be modified
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with the addition of reinforcing fillers, colours, foaming agents, flame retardants, plasticisers etc. to meet the demands of the specific application. For these reasons and more, plastics are being used more and more in: 1. Packaging 2. Building and construction 3. Transport 4. Electrical and electronics 5. Agriculture 6. Medical 7. Sports Basically these plastics are man-made. In principle any combination of properties can be developed to accommodate almost any application you can think of.
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