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

Chapter 5
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Other technological properties like hardness, compression set values
and abrasion loss for gum vulcanizates are given in Table5.5. Hardness,
compression set and abrasion loss for C-1, C-2, and C-3 vulcanizates are
superior compared to C-4 vulcanizate. It is clear from the table that the
hardness and compression set values of C-2 and C-3 vulcanizates are
comparable with C-1 vulcanizate. The abrasion loss values for C-2 and C-3
vulcanizates are reduced compared to C-1 vulcanizate. This indicates that low
dosage of ZnO(p) and ZnO(s) are enough to get the same strength as that
with higher dosage of conventional ZnO. This may be due to the smaller
particle size of ZnO(p) and ZnO(s). 8
5.3.3 Properties of filled vulcanizates
Tensile properties
Composite
Table 5.6 Tensile properties of filled vulcanizates
Tensile strength
MPa
Tensile modulus at300%
elongation (MPa)
Elongation
at break (%)
Tear strength
N/mm
C-5 19.82 8.42 489 53
C-6 18.53 8.46 478 64
C-7 19.48 8.91 468 60
C-8 15.28 7.82 499 50
C-9 14.72 3.68 791 49
C-10 14.91 4.10 712 52
Table 5.6 shows the comparative evaluation of tensile properties of
filled vulcanizates.
Filled vulcanizate with 2phr conventional ZnO (C-8) has low tensile
properties compared to vulcanizate with 5phr conventional ZnO (C-5). It is
seen that tensile properties of C-6 and C-7 vulcanizates are superior to that of
C-9 and C-10 vulcanizates. But the values are comparable to that with 5phr
conventional ZnO (C-5). This again confirms that the optimum dosage of
ZnO(p) and ZnO(s) is 2phr. Tear strength showed more improved values for
2phr ZnO(p) and ZnO(s) vulcanizates. These values are superior to that of