03.08.2013 Views

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 ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Use <strong>of</strong> <strong>nano</strong> <strong>z<strong>in</strong>c</strong> <strong>oxide</strong> <strong>in</strong> chloroprene rubber<br />

c<strong>on</strong>venti<strong>on</strong>al ZnO vulcanizate. As <strong>the</strong> re<strong>in</strong>forc<strong>in</strong>g capacity <strong>in</strong>creases,<br />

generally <strong>the</strong> el<strong>on</strong>gati<strong>on</strong> at break (%) decreases. Vulcanizates with 2phr<br />

ZnO(p) <strong>and</strong> ZnO(s) show reduced el<strong>on</strong>gati<strong>on</strong> at break values compared to<br />

that <strong>of</strong> vulcanizate with 5phr c<strong>on</strong>venti<strong>on</strong>al ZnO. This aga<strong>in</strong> shows that 2phr<br />

ZnO(p) <strong>and</strong> ZnO(s) are better curatives than c<strong>on</strong>venti<strong>on</strong>al ZnO.<br />

O<strong>the</strong>r technological properties<br />

Table 5.7 Technological properties <strong>of</strong> filled vulcanizates<br />

Property C -5 C –6 C-7 C - 8<br />

Hardness (Shore A) 67 69 69 62<br />

Compressi<strong>on</strong> set (%) 19.12 16.91 17.36 20.84<br />

Abrasi<strong>on</strong> loss (cc/hr) 2.68 2.40 2.41 2.8<br />

Heat build-up(∆T) o C 13.2 12.2 13.3 13.9<br />

Flex resistance ( k cycles) 35.62 39.44 62.86 30.35<br />

The technological properties like hardness, compressi<strong>on</strong> set, abrasi<strong>on</strong><br />

loss, heat build-up <strong>and</strong> flex resistance were compared for <strong>CR</strong> vulcanizates<br />

with ZnO(p), ZnO(s) <strong>and</strong> c<strong>on</strong>venti<strong>on</strong>al ZnO <strong>and</strong> is given <strong>in</strong> <strong>the</strong> Table 5.7.<br />

Hardness, compressi<strong>on</strong> set, abrasi<strong>on</strong> loss, heat build-up <strong>and</strong> flex resistance for<br />

C-5, C-6 <strong>and</strong> C-7 vulcanizates are superior compared to C-8 vulcanizate.<br />

Abrasi<strong>on</strong> resistance, compressi<strong>on</strong> set <strong>and</strong> flex resistance are found to be<br />

superior for C-6 <strong>and</strong> C-7 vulcanizates. Hardness <strong>and</strong> heat build-up values <strong>of</strong><br />

C-6 <strong>and</strong> C-7 vulcanizates are comparable with that <strong>of</strong> C-5 vulcanizate with<br />

5phr c<strong>on</strong>venti<strong>on</strong>al ZnO. This <strong>in</strong>dicates low dosage <strong>of</strong> ZnO(p) <strong>and</strong> ZnO(s) are<br />

better curatives than high dosage <strong>of</strong> c<strong>on</strong>venti<strong>on</strong>al ZnO.<br />

Re<strong>in</strong>forc<strong>in</strong>g <strong>in</strong>dex<br />

Re<strong>in</strong>forc<strong>in</strong>g <strong>in</strong>dex values <strong>of</strong> composites with respect to tensile strength<br />

are given <strong>in</strong> <strong>the</strong> Table 5.8.<br />

98

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!