Chemistry of Rubber

There are two types of rubber: synthetic and natural. Natural rubber has a different chemical composition from synthetic rubber. Because there are many different kinds of synthetic rubber, each with their own chemical composition, let’s start with the chemistry and manufacturing process of natural rubber. This process is complicated and can be difficult to understand. Here is the layman’s version:

  1.Latex sap-containing isoprene molecules-seeps from a rubber tree.

  2.As the sap dries, the isoprene molecules attack nearby bonds.

  3.When these bonds break, the electrons rearrange to form a bond between the isoprene molecules.

  4.This continues until a long chain of isoprene molecules form, called polyisoprene polymers.

  5.The sap continues to dry and the polyisoprene chains start to stick together through electrostatic bonds creating rubber.

  6.When the temperature heats up, the bonds loosen and the rubber becomes sticky and elastic.

  7.As temperatures cool down, the bonds tighten and the rubber begins to crack.

Once the rubber compound has gotten to this point, it is ready to be vulcanized. Vulcanization takes natural ingredients through another reactionary process, creating a durable and recognizable rubber.