Q. Natural rubber and Synthetic rubber?

There is often a confusion between the words elastomer and neoprene. While elastomer refers to the generic name of the rubber, neoprene refers to the trade name of the elastomer of one of the leading rubber manufacturers. Engineers are more familiar with materials which obey Hooke's Law i.e. behaving in a linear elastic manner. We understand elastomers less well than we do concrete or steel because elastomers do not obey Hooke's Law. They are very flexible in shear but very stiff in bulk compression. The simple theory of mechanics characterizing the behaviour of rubber is quite different from that used for conventional materials, and quite complex for the liking of the practical engineers.