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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><br />

natural rubber, chloroprene rubber <strong>and</strong> styrene<br />

butadiene rubber<br />

7.1 Introducti<strong>on</strong><br />

VÉÇàxÇàá<br />

7.1 Introducti<strong>on</strong><br />

Part- A<br />

Use <strong>of</strong> antioxidant <strong>modified</strong> <strong>silica</strong> <strong>in</strong> natural rubber<br />

7.2 Experimental<br />

7.3 Results <strong>and</strong> discussi<strong>on</strong><br />

Part- B<br />

Use <strong>of</strong> antioxidant <strong>modified</strong> <strong>silica</strong> <strong>in</strong> chloroprene rubber<br />

7.4 Experimental<br />

7.5 Results <strong>and</strong> discussi<strong>on</strong><br />

Part - C<br />

Use <strong>of</strong> antioxidant <strong>modified</strong> <strong>silica</strong> <strong>in</strong> styrene butadiene rubber<br />

7.6 Experimental<br />

7.7 Results <strong>and</strong> discussi<strong>on</strong><br />

7.8 C<strong>on</strong>clusi<strong>on</strong>s<br />

7.9 References<br />

Incorporati<strong>on</strong> <strong>of</strong> precipitated <strong>silica</strong> <strong>in</strong> rubber is quite different from<br />

that <strong>of</strong> carb<strong>on</strong> black. Carb<strong>on</strong> black is re<strong>in</strong>forc<strong>in</strong>g filler for hydrocarb<strong>on</strong><br />

rubbers. 1 S<strong>in</strong>ce both are hydrophobic substances, mix<strong>in</strong>g <strong>and</strong> re<strong>in</strong>forcement<br />

problems do not usually arise when <strong>the</strong>se two are mixed. Precipitated <strong>silica</strong>,<br />

which is <strong>of</strong> m<strong>in</strong>eral orig<strong>in</strong> is <strong>on</strong>e <strong>of</strong> <strong>the</strong> most promis<strong>in</strong>g alternatives to<br />

carb<strong>on</strong> black as for as re<strong>in</strong>forcement is c<strong>on</strong>cerned. Precipitated <strong>silica</strong> is <strong>use</strong>d<br />

as re<strong>in</strong>forc<strong>in</strong>g filler <strong>and</strong> have particle sizes as small as <strong>the</strong> carb<strong>on</strong> black<br />

besides an extremely reactive surface. 2 Different types <strong>of</strong> syn<strong>the</strong>tic <strong>silica</strong> are;<br />

precipitated, pyrogenic, aerogels <strong>and</strong> hydrogels. Of <strong>the</strong>se varieties,<br />

precipitated <strong>silica</strong> <strong>and</strong> pyrogenic (fumed) <strong>silica</strong> are be<strong>in</strong>g <strong>use</strong>d for elastomer<br />

re<strong>in</strong>forcement. 3 Pyrogenic <strong>silica</strong> is too active <strong>and</strong> expensive. Precipitated <strong>silica</strong><br />

is a promis<strong>in</strong>g n<strong>on</strong>-black filler for rubber vulcanizates. It can be <strong>use</strong>d to

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