Hey!There

First of all congrats for getting chemical engineering at university of Calcutta.Chemical stream is good stream and it also has great scope if you have genuine interest in it Otherwise all Branch not meant for you if you don't have intrest.You won't get any core stream with this rank.You can get polymer Science Techology with this rank.I would like to suggest you that you should stick with chemical stream..

I hope above information will be helpful to you..

GOOD LUCK!