Studies on the use of nano zinc oxide and modified silica in NR, CR ...
Studies on the use of nano zinc oxide and modified silica in NR, CR ...
Studies on the use of nano zinc oxide and modified silica in NR, CR ...
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Use <strong>of</strong> antioxidant <strong>modified</strong> precipitated <strong>silica</strong> <strong>in</strong> natural rubber,<br />
chloroprene rubber <strong>and</strong> styrene butadiene rubber<br />
better abrasi<strong>on</strong> resistance also po<strong>in</strong>ts towards better b<strong>on</strong>d<strong>in</strong>g with <strong>the</strong> <strong>silica</strong><br />
filler. The lower heat build-up may be due to <strong>the</strong> smooth surface <strong>of</strong> <strong>silica</strong> filler<br />
due to <strong>the</strong> antioxidant coat<strong>in</strong>g which acts as lubricant. The number <strong>of</strong> flex<br />
cycles required for crack <strong>in</strong>itiati<strong>on</strong> was noted <strong>and</strong> it is comparatively high for<br />
vulcanizates filled with antioxidant <strong>modified</strong> <strong>silica</strong>. The flex resistance is<br />
dependent <strong>on</strong> <strong>the</strong> network <strong>of</strong> <strong>the</strong> vulcanizates <strong>and</strong> it is found to be superior<br />
for <strong>the</strong> vulcanizate with antioxidant <strong>modified</strong> <strong>silica</strong>.<br />
7.7.4 Thermal age<strong>in</strong>g studies<br />
Figure 7.9 (a)Variati<strong>on</strong> <strong>of</strong> tensile strength <strong>of</strong><br />
SBR vulcanizates (I-1 <strong>and</strong> I-2 ) with<br />
time <strong>of</strong> age<strong>in</strong>g at 100°C<br />
Modulus at 300% el<strong>on</strong>gati<strong>on</strong><br />
(N/mm 2 )<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
0 24 48 72<br />
Time (Hours )<br />
Figure 7.9(c) Variati<strong>on</strong> <strong>of</strong> modulus <strong>of</strong> <strong>the</strong> SBR<br />
vulcanizates (I -1 <strong>and</strong> I-2) with time <strong>of</strong> age<strong>in</strong>g<br />
at 100°C<br />
El<strong>on</strong>gati<strong>on</strong> at break (%)<br />
1000<br />
900<br />
800<br />
700<br />
600<br />
500<br />
400<br />
300<br />
0 24 48 72<br />
Time (Hours )<br />
Figure 7.9(b) Variati<strong>on</strong> <strong>of</strong> el<strong>on</strong>gati<strong>on</strong> at<br />
break <strong>of</strong> SBR vulcanizates (I-1 <strong>and</strong> I-2)<br />
with time <strong>of</strong> age<strong>in</strong>g at 100°C.<br />
(Antioxidant <strong>modified</strong> precipitated <strong>silica</strong> filled<br />
vulcanizate)<br />
(Neat precipitated <strong>silica</strong> filled vulcanizate.)<br />
145