Mylar ® polyester film retains good physical properties over a wide temperature range (–70 to 150 ° C [–94 to 302 ° F]), and it is also used at temperatures from –250 to 200 ° C (–418 to 392 ° F) when the physical requirements are not as demanding.

Mylar ® has a shear strength that is significantly higher than published data for other polymeric materials such as acetals, nylons, and polyolefins.

Mylar ® is unusually resistant to creep. Two values measured at room temperature are 0.1% after 260 hr at 2.09 kg/mm 2 (2.98 kpsi) and 0.2% after 1000 hr at 2.10 kg/mm 2 (3.00 kpsi). After 4000 hr at 0.35 kg/mm 2 (0.50 kpsi) in 100 ° C (212 ° F) oven, a creep of 0.9% was measured.

The thermal coefficient of linear expansion of Mylar ® is 1.7 × 10 –5 in/in/ ° C (9.5 × 10 –6 in/in/° F).