PEN (Polyethylene naphthalate), commonly known by Honeywell's trade name "Pentex", is another kind of polyester fiber, which stretches only 40% as much as standard PET fibers, but about twice as much as Kevlar 29.
Polyethylene terephthalate | polyethylene | Low-density polyethylene | High-density polyethylene | Polyethylene | Linear low-density polyethylene | Polyethylene naphthalate | Cross-linked polyethylene |