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Perhaps few industrial products of the 20th century have changed the way we live as much as the discovery of plastics. With it's almost limitless applications, plastic now plays a major role in the consumer marketplace and our everyday life. Indeed plastic production throughout the world today significantly exceeds that of steel, with the manufacturing rate expanding steadily.
HISTORY The period between 1920 and 1940 saw many new discoveries emerge on the market which would eventually have a significant impact on the way we now live. These products included polyvinylchloride (PVC), vinyl urea-formaldehyde resins, acrylic resins (foam) polyethylene, polytetrafluorethene (PTFF or Teflan) and the synthesis of nylon. Polyethylene, one of the most common plastics around today, was first discovered in 1938 at ICI England by two scientists, Fawcett and Fibson. It was used almost exclusively during the war to insulate radar cables. A true commercial extraction process was not invented until 1953 by German scientist Karl Ziegler. In 1954 Italian chemist Criulio Natta developed polypropylene. Both scientists earned the Nobel Prize for Chmeistry in 1963.
CHEMICAL MAKEUP AND CLASSIFICATION OF PLASTICS The processibility of plastics largely depends on whether they are thermoplastic or thermosetting. Thermoplastics are made up of linear or branched polymers that are fusible, meaning they soften when heated and harden when cooled (this can also be the case with some cross linked thermosets also). In the solid state, polymer chains become immobilised due to physical forces preventing them from slipping past each other. Heat causes the thermal energy to increase, overcoming these forces and allowing the material to soften. A characteristic of thermoplastics is that the material can generally be granulated and remoulded with a minimum loss of its mechanical properties. The capabilited of thermoplastic allow the plastic to be formed during the molten resin phase enabling the material to be extruded or moulded into a variety of shapes.
 Thermosets generally harden when heated, and a cross linking of molecules takes place in true thermosets after the plastics have been formed.
During the early era of plastic development, most plastic resins were made from vegetable derivatives such as cellulose from cotton, seed oils, oat hulls, starch derivatives, coal and casein. Today almost all plastics derive from the petrochemical industry. By processing crude oil or its by-products, with refining and distillation a raw material can be produced to form the base material of a plastic product. With further processing and the inclusion of chemical additives such as anti-oxidants, ultra-violet stabilisers, calcium carbonate, plasticisers, flame retardants and antistatics, the resultant product is ready for shaping by extrusion or compression moudling.
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John Hyatt is largely credited with one of the first formal scientific breakthrough in plastic after formulating proxylin (Celluliod) in 1869 in an attempt to find a substitute for ivory pool balls. In 1906 Leo Henrik Bacland discovered phenolformaldehyde resin (Bakelite). When in 1920 German scientist Hermann Standinger proved that plastics were truly giant molecules, a new and exciting wave of scientific discovery commenced in the plastic-chemical industry.| AHSCA - [Website] | [Articles] |
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