Effect of Functionalization of Carbon Black on Rubber Properties

0.24
0.21
0.18
0.15
0.12
0.09
0.06
0.03
0.00
measurement, CRX2124 shows a 24% reduction in tan δmax relative to the carbon black
control and this difference is further increased to 33% by the addition <strong>of</strong> 1.0 phr TESPT.
Both results from strain and temperature sweeps suggest that owing to its lower hysteresis
at high temperature, CRX2124 will give substantially lower rolling resistance in relation to
carbon black.
Abrasion resistance
tan δ max
N110
CRX2124 +
TESPT 1.0 phr
As discussed earlier, with regard to abrasion resistance, silica has a significant deficiency in
polymer-filler interaction. In NR, the deficiency cannot be effectively compensated for by
chemical linkages between polymer molecules and the silica surface via the coupling agent
as the reactive groups, i.e., silanols may be blocked by adsorbed non-rubbers. 12 This could
also be applied to the silica domain on CSDPF. However, as indicated in Figure 15, the
abrasion index <strong>of</strong> the CRX2124-filled compound measured at 7% slip ratio is only about
17% lower than its carbon black counterpart. The negative impact <strong>of</strong> the silica domain on
the abrasion resistance seems to be partially <strong>of</strong>fset by the high surface activity <strong>of</strong> carbon
domain on the aggregates. By addition <strong>of</strong> 1.0 phr TESPT, the abrasion resistance <strong>of</strong>
CRX2124 can be further improved, making it closer to that <strong>of</strong> carbon black N134, one <strong>of</strong>
the preferred reinforcing fillers for truck tire tread.
18
NR, Filler: 50 phr
70°C, 10 Hz
CRX2124
Figure 14. Comparison <strong>of</strong> tan δ max <strong>of</strong> NR compounds filled with a variety <strong>of</strong> fillers