Fig.6. Storage modulus of the DSNR/PP blend with various types of vulcanization systems.
Fig.7.Tan
δ
of the DSNR/PP blend with various types of vulcanization systems.
5. Morphological properties
SEM micrographs of the xylene etched cryogenic fracture surface of dynamically cured DSNR/PP blends
are shown in Figure 8. The PP phase was preferentially dissolved in xylene at an elevated temperature which left
spherical vulcanized rubber particles adhering at the surfaces. The two-phase morphology was confirmed observed with
micron size spherical domains of dispersed vulcanized DSNR phase in the PP matrix. It is seen that the TPV with sulphur
and mixed sulphur-peroxid cured systems showed the smallest vulcanized rubber particles dispersed in the PP matrix,
whilst the phenolic cure system gave the largest rubber particles. The TPV with peroxide cured system showed
intermediate particle size. Smaller vulcanized rubber domains were a result of higher interfacial force between the rubber
domain and the PP continuous phase. In the TPV with phenolic cured system, PP is capable of reacting with phenolic
molecules to form larger particle domains.
1
10
100
0.1
1
10
100
Frequency (Hz)
Storage modulus (KPa)
Phenolic
Peroxide
Sulphur + Peroxide
Sulphur
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Frequency (Hz)
Tanδ
Phenolic
Peroxide
Sulphur + Peroxide
Sulphur
Mixed sulphur/peroxide system
Sulphur system
