Question

what will happen if cocoon is not boiled

Answer 1

It is important to boil cocoons to obtain silk fibers. After boiling, the silk fibers easily separate and we get long continuous silk thread. Boiling the cocoon helps to dissolve the adhesive that sticks the fibres together.

If cocoon is not boiled, the fibres obtained will be brittle, and we will get fragments of the thread instead of a long continuous silk thread. Moreover, it would be impossible to spin it into a thread.