the double bond in these compound is highly sensitive to the (Ozone).it craeates a radical,it breaks the all double in the polymer and weakens and the tire loses it.elasticity.polyurethane and polyisobutylene are not affect by Ozone. Solution the double bond in these compound is highly sensitive to the (Ozone).it craeates a radical,it breaks the all double in the polymer and weakens and the tire loses it.elasticity.polyurethane and polyisobutylene are not affect by Ozone..