What type of clothing materials are worn by astronauts and fireman and Why?

Astronauts wear specialized materials like Nomex and Kevlar, which provide thermal protection and are resistant to extreme temperatures, radiation, and abrasion. Firefighters also use Nomex and similar flame-resistant fabrics to protect against high heat and flames while allowing breathability and flexibility. Both types of clothing prioritize safety and durability to withstand hazardous environments.