Silica-Reinforced Natural Rubber: Synergistic Effects by Addition of Small Amounts of Secondary Fillers to Silica-Reinforced Natural Rubber Tire Tread Compounds

Table 1

Compound formulations used for this study.

Ingredients	Dosage (phr)
	Silica reference	Silica/secondary filler
Natural rubber (RSS#3)	100.0	100.0
Silica (ULTRASIL 7005)	55.0	45.0
Secondary filler	—	10.0
TESPD	5.0	4.1
TDAE oil	8.0	8.0
ZnO	3.0	3.0
Stearic acid	1.0	1.0
TMQ	1.0	1.0
DPG	1.1	0.9
CBS	1.5	1.5
Sulfur	1.5	1.5

Carbon black N134 (CB) or organoclay Dellite 67G (OC).