A perfectly crystalline polymer would have a very small elastic regime. That's because Van der Waals forces holding the crystallites together act over such a short range. Disrupting them would pull the crystallites apart and cause the material to deform plastically.
If I remember correctly, the third law of thermodynamics defines the entropy of a perfect crystal at absolute zero to be zero. Since crystalline polymers never reach 100% crystallinity, that would imply that they cannot reach zero entropy. However, sort of reversing the logic, does the amorphous structure within polymer crystals influence the minimum temperature that can be achieved with the polymer crystal? In other words, is the lowest temperature limit of polymer crystals higher than the lowest temperature limit of small molecule crystals?
That's an excellent question. Honestly I don't know. Your reasoning related to polymer samples does indeed seem logical since polymer chains in void volumes will be less constrained than atoms in a lattice.
Definitely! Mylar is a good example. It is biaxially oriented polyethylene terephthalate (BOPET). Sometimes it is metallized with a sputterer to make a shiny surface, like Mylar balloons.
Question, after the material has yielded and you stopped the elongation or stretching, would the material recover (some amount) or it will be 100% of plastic deformation without any recovery?
