Influence of particle size on inhomogeneity in rubber compositions of NR/BR blend wear particles by single particle analysis

Abstract

AbstractTire wear particle has been considered as one of environmental pollution sources and its sizes are widely ranged from PM2.5 to several hundred micrometer (μm). A bus tire tread is generally composed of NR and BR. In the present work, difference in the rubber compositions of wear particles of a model bus tire tread compound (NR/BR = 80/20) depending on the particle size was investigated by the single particle analysis using Py‐GC/MS. The wear particles were obtained using a laboratory abrasion tester. The wear particles were separated by size using a sieve shaker and those of 212–500, 106–212, and 63–106 μm were used. The rubber composition of each single particle was determined using the principal pyrolysis product ratio of 4‐vinylcyclohexene and dipentene produced from BR and NR, respectively. For the wear particles of 212–500 μm, the rubber compositions were nearly the same to the bulk (the abrasion specimen) and the differences among them were small. But the rubber compositions of the wear particles of below 212 μm were different each other. Some wear particles of 106–212 μm had very high BR composition above 70 wt%. For the wear particles of 63–106 μm, some wear particles had very low BR composition of nearly to zero BR. Difference in the rubber compositions from the bulk tended to be larger by decreasing the wear particle size. The analytical results were explained by the distribution of BR in NR and abrasion position.