Oxidation/Decomposition of Chewing Gum Blots

[Islam Hassan]

Why is the oxidation/decomposition of chewing gum blots stuck on pavements such a slow affair? Why do these blots persist for such a very very long time before being weathered away? What molecular components give chewing gum this great chemical stability?IH

 

[256bits]

This is quite a good explanation.
http://www.scienceinschool.org/2008/issue9/chewinggum