Abstract
The chemical structure of the tread vulcanizate of heavy-duty tires has been investigated before and after service on the road, and after testing under conditions designed to induce tread-lift. Significant changes occurred. These included a marked reduction in the concentration of polysulfide crosslinks, and an increase in the amount of monosulfide crosslinks and main chain modification. Experiments with vulcanizates made in the laboratory indicated that the structural alterations in the tires were due to thermal anaerobic reactions caused by heat build-up, and that they resulted in a deterioration in some of the physical properties of the tread vulcanizate. The rate of desulfuration of ‘model’ polysulfides has been found to depend critically upon the nature of the vulcanization recipe. These novel findings point the way to improving the stability of vulcanizates used in the treads of tires and, consequently, tire performance.
Solid Particle Number Emission Factors of Euro VI Heavy-Duty Vehicles on the Road and in the Laboratory
