I was travelling in a taxi and one of the seats scratched my thighs. there was no blood coming out. is there any chance of me contracting hiv like this?

No: HIV cannot be transmitted through above mentioned mechanism. Hand hygiene rules still apply as to risk for transmission for other germs.

Agree with Dr. P: You have virtually no risk. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine. Wish you good health!