Studies on the use of nano zinc oxide and modified silica in NR, CR ...

Swelling resistance in other solvents
Use of nano zinc oxide in styrene butadiene rubber
The swelling index of all gum and filled composites in various
solvents are given in Table 6.8.
Table 6.8 Swelling index of gum and filled SBR vulcanizates
Solvent S-1 S-2 S-3 S-5 S-6 S-7
Petrol 1.70 1.73 1.64 0.76 0.74 0.71
Diesel 1.66 1.70 1.65 0.80 0.80 0.80
Cyclohexane 2.37 2.36 2.27 1.05 1.00 1.01
The swelling index of the samples in different solvents was studied by
keeping the sample of known weight in solvent for equilibrium swelling.
Table 6.8 shows the swelling index of the vulcanizates with 2phr ZnO(p),
2phr ZnO(s) and 5phr ZnO(c). These values are found to be comparable for
vulcanizates with 2phr ZnO(p), 2phr ZnO(s) and 5phr ZnO(c).
6.3.5 Thermal ageing
Ageing resistance of the vulcanizates with 2phr ZnO(p), 2phr ZnO(s)
and 5phr ZnO(c) are assessed by measuring the tensile properties after ageing
to 96 hours and are shown in the Figure 6.4 (a-d).
Tensile Strength (Mpa)
14
12
10
8
6
4
2
12.02
11.59
10.95
ZnO(s)
ZnO(p)
11.94
ZnO (c)
10.99
10.65
10.98 9.66
0
0 48
Time(Hours)
96
Figure 6.4 (a) Variation in tensile strength of SBR vulcanizates with time of ageing at
100°C
9.08
114