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

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Chapter 8<br />

mesoporous <strong>silica</strong> composite. The rate <strong>of</strong> degradati<strong>on</strong> showed no<br />

c<strong>on</strong>siderable change.<br />

160<br />

Sample<br />

Sample I<br />

(meso)<br />

Sample II<br />

(ppt)<br />

Weight (%)<br />

120<br />

100<br />

80<br />

60<br />

40<br />

20<br />

0<br />

-0.5<br />

0 200 400 600 800<br />

Temperature (°C)<br />

––––––– meso.001<br />

– – – – ppt.001<br />

Figure 8.5 Thermograms <strong>of</strong> <strong>the</strong> composites<br />

2.0<br />

1.5<br />

1.0<br />

0.5<br />

0.0<br />

Deriv. Weight (%/°C)<br />

Universal V4.2E TA Instruments<br />

Table 8.4 Thermogravimetric values <strong>of</strong> composites<br />

Initiati<strong>on</strong><br />

temp. 0 C<br />

Max.deg<br />

temp. 0 C<br />

Rate at<br />

max deg.<br />

%/ 0 C<br />

Completi<strong>on</strong><br />

temp. 0 C<br />

25% degg<br />

Temp 0 C<br />

Residue %<br />

321.7 391.97 1.670 495.36 321.79 14.81<br />

316.2 388.17 1.672 461.05 316.26 12.69<br />

8.3.6 Soxhlet extracti<strong>on</strong> studies<br />

Acet<strong>on</strong>e extractable <strong>of</strong> <strong>NR</strong> vulcanizates is shown <strong>in</strong> Table 8.5.<br />

Table 8.5 Acet<strong>on</strong>e extractable <strong>of</strong> <strong>NR</strong> vulcanizates<br />

Vulcanizates Acet<strong>on</strong>e extractable (%)<br />

A 5.93<br />

B 6.47

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