WW1 Paracord

My father was a Marine in WW1. He was in an observation balloon unit in Germany. They would send someone up in a tethered hot air balloon to try and spot enemy forces. The observer would drop messages tied to rocks when he spotted any German troops. If the observer started taking enemy fire, He would parachute out of the balloon to safety, and one of the ground personnel would pull a rip cord on the balloon to let out the hot air and cause it to settle to the ground. My father brought home a parachute and my mother made sheets out of it. The parachute canopy was made of silk. We had a bunch of the paracord laying around, and it eventually got used up. I don't know what the paracord was made of since nylon wasn't invented until the 1930s. It looked like what is used today however. Does anyone have any ideas? Silk maybe? I don't know.