Lecture 8: Polymer Properties 1-1

It would be difficult to imagine our modem world without plastics. Today they are an integral part of everyone’s lifestyle with applications varying from commonplace domestic articles to sophisticated scientific and medical instruments.
Nowadays designers and engineers readily hun to plastics because they offer combinations of properties not available in any other materials. Plastics offer advantages such as lightness, resilience, resistance to corrosion, colour
fastness, transparency, ease of processing, etc., and although they have their limitations, their exploitation is limited only by the ingenuity of the designer.
The term plastic refers to a family of materials which includes nylon, polyethylene and PTFE just as zinc, aluminium and steel fall within the family of metals. This is an important point because just as it is accepted that zinc
has quite different properties from steel, similarly nylon has quite different properties from ITFE. Few designers would simply specify metal as the material for a particular component so it would be equally unsatisfactory just to
recommend plastic. This analogy can be taken still further because in the same way that there are different grades of steel there are also different grades of, say, polypropylene. In both cases the good designer will recognise this and
select the most appropriate material and grade on the basis of processability, toughness, chemical resistance, etc.