ME 2733 Chapter : Rubbers
Document Summary
Rubbers fall under the category of superelastic materials and are termed elastomers. Their elastic deformation is one to two orders of magnitude larger than that of a regular plastic such as polyethylene. Their modulus of elasticity and strengths are proportionately lower. On account of their highly elastic characteristics they are highly flexible and damp mechanical vibrations very efficiently. As stated for plastics, the rubbers too undergo glass transition. There is a natural rubber occurring in the rubber tree plant. The rubber molecule involved is called isoprene, which can be better understood from the starting basic rubber molecule known as butadiene. The latter is a linear hydrocarbon molecule (aliphatic) with the formula c4h6 and two unsaturated double bonds between the end and inner carbon atoms of the molecule. The polymerization requires both the double bonds to be broken and substituted with single bonds in their places.
