Effect of Functionalization of Carbon Black on Rubber Properties

compounds. With this filler, the high polymer-filler interaction will ensure abrasion
resistance and the lower filler-filler interaction resulting in lower hysteresis, hence lower
rolling resistance.
The impact <strong>of</strong> the characteristics <strong>of</strong> CRX2124 on truck tire tread compounds was
investigated experimentally, taking carbon black N134, a currently used highly reinforcing
filler in truck tread compounds, as a reference. Morphologically, CRX2124 is similar to
carbon black N134 but contains 4.1% silicon. The formulations used for the investigation
are typical for truck tire tread compounds (Table III). In the case <strong>of</strong> CRX2124, the dosages
<strong>of</strong> curatives were adjusted according to their cure characteristics. Additionally, one <strong>of</strong> the
compounds contains 1.0 phr coupling agent TESPT.
Dynamic properties (rolling resistance):
As shown in Figure 13, over the temperature range from 50 to 80°C, the CRX2124
compound gives substantially lower hysteresis than the carbon black compound, and
further reduction in tan δ can be obtained by the addition <strong>of</strong> TESPT. At lower
temperatures, the compounds filled with CRX2124 give significantly higher hysteresis.
However, the reduction in tan δ due to the silane is <strong>of</strong> a much smaller degree compared to
the OE-SSBR/BR formulation. This observation is also supported by strain sweeps. Shown
in Figure 14 are the maximum loss factors, tan δmax, obtained from strain sweeps at 70°C.
Similar to the results obtained at high temperature from the temperature sweep
2.0
1.0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
tan δ
CRX 2124
0.1
0.08
0.07
0.06
0.05
T, °C
CRX2124/
TESPT 1.0 phr
-100 -80 -60 -40 -20 0 20 40 60 80 100
Figure 13. Temperature dependences <strong>of</strong> tan δ at strain amplitude 2.5% and 10 Hz for NR compounds with CRX2124 and N134
17
NR, Filler: 50 phr
Strain 2.5%, 10 Hz
N134