Aging properties in terms of change in tensile strength and elongation at break of the dynamically cured
DSNR/PP blends are shown in Figure 4 and 5, respectively. It can be seen that the mixed sulphur-peroxide cured system
shown the lowest negative change in elongation at break but the highest positive change in tensile strength. This is due to
effect of phosphate groups attached in the NR molecules which increase strength and heat resistant properties.
Fig. 4. The % change of tensile strength of the DSNR/PP blend with various types of vulcanization systems.
Fig. 5. The % change of elongation at break of the DSNR/PP blend with various types of vulcanization systems.
4. Dynamic properties
Figure 6 shows storage modulus as a function of angular frequency of dynamically cured 60/40 DSNR/PP
blends with various curing systems. It can be seen that the sulphur and mixed sulphur-peroxide cured systems exhibited
the highest storage modulus, which reflect to the highest elastic response. Furthermore, the TPV with the phenolic cured
systems showed the intermediate value and the peroxide showed the lowest value of storage modulus. Increase in storage
modulus relate to increasing crosslinking density of the DSNR phase to gather with higher interfacial adhesion between
DSNR and PP phases.
Figure 7 shows tan
δ
as a function of angular frequency. It can be seen that among four types of curing
systems, the peroxide cured systems exhibited the highest value of tan
δ
, followed by phenolic, mixed sulphur-peroxide
and sulphur cured system. This indicates the lowest elastic response of TPV based on peroxide cured system.
-10
-5
0
5
10
15
20
Phenolic
Peroxide
Sulphur+Peroxide
Sulphur
Vulcanization systems
Change of tensile strength (%))
-450
-400
-350
-300
-250
-200
-150
-100
-50
0
Phenolic
Peroxide Sulphur+Peroxide
Sulphur
Vulcanization systems
Change of elongation at break (%))
