Natural rubber is a linear polymer of isoprene i.e., 2-methyl-1, 3-butadiene.In the polymer double bonds are located between C2 and C3 isoprene units. The cis-polyisoprene molecule consists of various chains held together by weak van der Waals interactions and has coiled structure. This cis-configuration about double bonds does not allow the chains to come closer for effective attraction due to weak van der Waals interactions. Thus, it can be stretched like a spring and exhibits elastic properties.