Short Notes:

Rubber can stretch, bend, and compress, then return to its original shape because of the way its molecules are organized. Rubber is a natural product extracted from certain kinds of trees. In its raw form, it is a colloid called latex, which is sticky and milky in colour. When is is chemically treated with sulphur in a process called vulcanization, rubber molecules link in strands, or polymers, which are built up with atoms of carbon and hydrogen. These kinked, looping polymers are intertwined. Because the bonds between the molecules of the polymers allow for some motion, the tangled polymers flex and expand when they are subjected to outside forces. When the outside force is removed, the chemical bonds in the chains exert an opposite force that causes the rubber to rebound to its former shape.

Structure of rubber: A snaking string of carbon atoms makes up the backbone of a rubber polymer. Each carbon atom acts as a pivot point around which linked molecules are free to rotate. This accounts for rubber's elasticity.

Vulcanized rubber: Untreated rubber is brittle when cold and sticky when hot. Dosed with sulphur in a process called vulcanization, invented in 1839 by American Charles Goodyear, rubber gains eleasticity and can be moulded into a variety of shapes.