A fabric made from nylon does not degrade enough over time to lose the weave spacing that was inherent to that fabric in the beginning
Hold on there Dr. If all sides of any textile were breached, as in say, cut by Cooper while making a makeshift pack for the money, then it will fray, just like the picture shows it doing. And over 46 years it'll slowly de-textile itself. I wouldn't take a bet here on even money, but I would definitely take odds here, that TC's find is nylon, and with all swearing it cannot be nylon, I'd figure its at least 6 to 1. If it were a cotton canvas, I'd expect much more dissolvement, being organic. Any takers ?
Nope. I'm sticking with the "burlap bag" theory.
In addition to the NB-6 post above, which is about three posts above this one, I want to add that I owned an NB-6 parachute until about November 1, 1971 or just about a month before the Cooper hijacking.
My 1971 NB-6 parachute was assembled in conjunction with a parachute rigger. I needed that particular parachute because it could be packed in a very thin container. And I used that as an emergency parachute in an aircraft with a very cramped cockpit.
Under the supervision of my rigger, I removed all extraneous straps, metal stiffeners, and everything else that wasn't absolutely necessary. The end result was a somewhat flexible parachute that could be worn in cramped cockpits, with a reasonable degree of comfort, for non-stop flights lasting more than six hours.
So I got a good look at everything that was in a pre-1971 manufactured NB-6 parachute. And there is nothing in an NB-6 that will translate into the "strap" shown in the pictures posted on this subject.