How does the presence of double bonds in rubber molecules influence their structure and reactivity?

Explanation

Natural rubber is cis-polyisoprene and is obtained by 1,4-polymerization of isprene units. In this polymer, double bonds are located between `C_(2) and C_(3)` of each isoprene unit. These cis-double bonds do not allow the polymer chains to come closer for effective interactions and hence intermolecular forces are quite weak. As a result, natural rubber, i.e., cis-polyisoprene has a randomly coiled structure not the linear one and hence show elasticity