If plastic was made in 1907 how do they know it may take up to 1000 years to decompose?

Question

If plastic was made in 1907 how do they know it may take up to 1000 years to decompose?

In: Chemistry

Answer 1

PhD in plastics engineering here. There’s a technique known as time-temperature superposition, which allows us to predict how long it will take to degrade plastics by subjecting the plastics to high temperatures (keeping most details out of it) and seeing how long it takes to degrade at this high temperature. Then we use this information to compute how long it will take the plastic to decompose at ambient (room) temperatures. This method gives a very precise number much more accurate that a qualitative 1000s of years. The most stable plastics would probably survive for 100s of years, not 1000s.