Molecular Foundry and Dow Inc. researchers demonstrated a new way of stretching freestanding thin films of plastic and measured extreme stretchiness in polystyrene films. They were able to stretch thin films of polystyrene up to three times their original lengths without the materials breaking. https://foundry.lbl.gov/2020/12/18/bouncing-ideas-between-berkeley-and-dow-to-create-stretchy-plastics/