Plastics

The word plastic comes from the Greek plastikos, means to mould. Plasticity is the ability to retain a deformation after the load, producing it has been removed. Plastics are particularly useful for applications, which involve relatively low-stress levels, where lightness is important and where low electrical or thermal conductivity is required.

The earliest plastic materials (before the synthetics) were those made from the sap or latex of certain trees (gutta-percha), the secretions of tiny, scaly insects (shellac) and the softened, moulded parts of the horns of animals.

In 1869, an American inventor, John Wesley Hyatt produced the first synthetic plastic material (used as an inexpensive substitute for ivory), from the cellulose of plants and called it Celluloid. While in 1909, a chemist, L H Baekeland developed the first entirely synthetic plastic material (Bakelite) from phenol-formaldehyde. Bakelite is hard and fairly brittle. It is widely used with a suitable filler material (mica or wood flour) for various electrical mouldings and low-stressed handles.

However, plastics is now the generic name that are used to identify various materials (natural and synthetic) based on long-chain molecules (polymers) of carbon that can be cast, extruded or moulded into various shapes or drawn out into filaments to be used as fibres.

While the two major groups of plastics are the thermoplastic and thermosetting compositions, the manufacture of synthetic rubbers (called Elastomers) is also considered to be part of the plastics industry.