Effect of Functionalization of Carbon Black on Rubber Properties

very low tan δ at high temperature and very high hysteresis at lower temperature, similar
to silica. The same results were also obtained in the strain sweep test (Figure 10). At
70°C, the maximum tan δ is 0.323 for the carbon black compound. This value is reduced
by 48% and 50% with CRX4210 and silica, respectively. Based on the well-known
correlation between rolling resistance and tan δ at high temperature, it can be expected
that the rolling resistance <strong>of</strong> CRX4210 tire is comparable to that <strong>of</strong> silica tires and much
lower than that <strong>of</strong> carbon black tires.
Abrasion resistance:
Due to the weak polymer-filler interaction between silica and hydrocarbon rubber, even
with a high dosage <strong>of</strong> coupling agent TESPT, the abrasion resistance <strong>of</strong> the silica
compound is still significantly poor relative to carbon black compound. This could also
be applicable for the silica domain in CRX4210 aggregates. However, this deficiency
would be partially compensated for by the high surface activity <strong>of</strong> the carbon domain <strong>of</strong>
the silica-containing fillers. Presented in Figure 11 are the abrasion resistance indexes
measured with the Cabot Abrader at a slip ratio <strong>of</strong> 14%. Although the abrasion resistance
<strong>of</strong> a compound filled with CRX4210 and 2.7 phr TESPT does not fully reach the level <strong>of</strong>
the carbon black compound, it is significantly better than the silica compound.
140
120
100
80
60
40
20
0
Abrasion index, %
N234
Silica +
TESPT 6.4 phr
13
OESSBR/BR 70/30,
Filler: equal volume
14% slip
CRX4210 +
TESPT 2.7 phr
Figure 11. Comparison <strong>of</strong> abrasion resistance <strong>of</strong> OE-SSBR/BR compounds filled with a variety <strong>of</strong> fillers