Question

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

Answer 1

Hi, please consider the answer below

Let's consider for instance a natural rubberwhich is normally linear cis-1,4-polyisoprene.

Its double bonds are present in between C2 & C3 of isoprene units.

Therefore again the effect is that cis configuration about double bonds does not allows the chains to come closer for effective intermolecular attraction due to weak intermolecular attractions.

Hence the natural rubber has coiled structure and therefore shows elasticity and is non crystalline.

Answer 2

$\huge\rm{\bigstar\underline{Answer :-}}$

Natural rubber is a linear cis-1, 4 polyisoprene in which double bonds are present between $C_2$ and $C_3$ of isoprene units. This cis configuration about double bonds does not allow the chains to come closer for effective intermolecular attraction due to weak intermolecular attractions.

Therefore, the natural rubber has a coiled structure and shows elasticity and is non-crystalline.

On the other hand, all trans configurations occur in gutta-percha which is trans-polyisoprene. These zig-zag chains pack more closely in gutta-percha and hence it is highly crystalline and non-elastic and is more hard and brittle than rubber.