Question

why does a knot tied on jute not slip easily as compared to silk thread?

Answer 1

The fibrous surface of the jute thread has high friction, so the knot doesn't slip easily. Silk thread is smooth and has low friction, so the knot may easily slip - the same goes for nylon thread.

Answer 2

The fibrous surface of the jute has more friction than the silky texture of the silk so the knot tied on silk won't remain for long whereas the knot tied on jute is more durable.