Question

What type of polymer is natural rubber?

Answer 1

Rubber is a type of elastomer type polymer which means that it can return to its original shape even if it is stretched. It is known to be in coiled form when resting. When there is tension present and it is stretched, it can elongate but when the tension is released, then it reverts back to how it was in the beginning.

Complete step-by-step answer: Conjugated diene monomers are known to be the main source of rubber polymer units. Dienes are the structure of alkenes with double bonds present.
When we talk about natural rubber, then we know that it is obtained as a milky white fluid which is called as latex from a tropical rubber tree. It is from isoprene which is a monomer and its formula is $\left( {2 - methyl - 1,3 - butadiene} \right)$. Following are the structures:

Isoprenes are conjugated diene hydrocarbons. It was discovered that when we mix sulfur and rubber, the properties of rubber are found to be improved such as it becomes tougher and it becomes resistant to heat and cold. This process is called Vulcanization. Due to vulcanization, it was found that the elasticity of rubber also increased. Natural rubber is the oldest type of rubber but still is found to be more than $40\%$ of total volume. Countries producing natural rubber today are Thailand, Vietnam, India and China.

Note: natural rubber is made by the process of cultivation of the tree Hevea brasiliensis. This originated from south America and is a naturally occurring high-cis poly-isoprene. There unique properties of natural rubber are caused due to resins and proteins which occur in it and some small amounts of dust, ash and water.