Fig.2. TGA thermograms of NR, ENR and DSNR.
3. Mechanical properties
Fig.3. shows stress-strain curves of dynamically cured 60/40 DSNR/PP blends with the four different types
of curing systems. It can be seen that the TPV based on the peroxide cured system showed the lowest tensile strength and
elongation at break, while the mixed sulphur-peroxide cured system exhibited the highest values. Typically, S-S and C-S
linkages are formed in the sulphur cured system, whilst more stable C-C linkages are formed in the peroxide cured
system. Therefore, in the mixed cured system S-S, C-S and C-C linkage are formed. However, in the peroxide cured
system, degradation of PP was observed because of reacting with DCP via
β
-scission mechanism, as shown in reaction
scheme 1.
Scheme 1.
β
-scission mechanism of PP by reacting with DCP (Nakason
et al
, 2006c).
Fig. 3. Stress-strain curves of the DSNR/PP blends with various types of vulcanization systems.
0
20
40
60
80
100
120
0
100
200
300
400
500
600
700
Temperature (
o
C)
Weight (%)
NR
ENR25
DSNR
0
2
4
6
8
10
12
0
20
40
60
80
100 120
140 160
180
Strain (%)
Stress (MPa)
DSNRPhenolic
DSNRPeroxide
DSNRSulphur+Peroxide
DSNRSulphur
