Rubber: High elastic polymer material having reversible deformation. Elastic at room temperature, can produce large deformation under the action of a small external force, can be restored to original state after removing external force. Rubber belongs to completely amorphous polymer, its glass transition temperature (T G) is low, the molecular weight is often large, more than hundreds of thousands.

The word rubber comes from the Indian word Cau-uchu, meaning "weeping tree." Natural rubber is by three leaf rubber tree cut latex outflow by solidification, drying and made. In 1770, British chemist J. Priestley discovered that rubber could be used to erase pencil writing. The term rubber is still used today. The molecular chain of rubber can be crosslinked. When the crosslinked rubber is deformed by external forces, it has the ability to recover quickly and has good physical and mechanical properties and chemical stability. Rubber is the basic material of double-sided adhesive, widely used in the manufacture of tires, rubber pipes, tapes, cables and other rubber products.

Three-leaf rubber trees provide the most commercial rubber. It secretes a large amount of SAP containing rubber emulsions when it is injured, such as when the bark on the stem is cut open.

In addition, FIG trees and some euphorbia plants can provide rubber. Germany tried to get rubber from these plants when its supply was cut off during World War II, but later switched to producing synthetic rubber.

The first rubber trees were grown in South America, but they have been artificially transplanted and are also grown in large numbers in Southeast Asia. In fact, Asia has become the most important source of rubber.

Rubber made from germinal gum can reduce sensitivity.