Evaluation of Some Conducting Polymers as Novel Antioxidants for Rubber Vulcanizates
Table 2
Rheometric characteristics and physico-mechanical properties of NR vulcanizates containing the prepared homopolymers and copolymers.
Property
Formulation no.
1
2
3
4
5
6
7
8
9
Rheometric characteristics at 142°C ± 1°C
Minimum torque, , dN·m
1.5
1
1
1
1.5
1
1
1
1.5
Maximum torque, , dN·m
64
66
66
70
68
72
68
67
66
Optimum cure time, , min
18
15
15
12
12
11
13
14
14
Scorch time, , min
8
6.5
5
5
6
5
6.5
4.5
6
Cure rate index, CRT, min−1
10
11.76
10
14.29
16.67
16.67
15.38
11.76
12.5
Physicomechanical properties at the optimum cure time
Stress at yield, , MPa
20.4
22.3
22
25.36
23.23
28.11
23.2
22.52
22.18
Stress at rupture, , MPa
19.3
21.2
21.8
25.11
23.11
27.4
22.05
22.33
21.83
Strain at yield, , %
496
530
525
645
539
650
535
530
530
Strain at rupture, , %
503
540
530
647
541
670
540
533
531
Equilibrium swelling, Q%
325
270
259
225
232
219
243
248
252
: minimum torque; : maximum torque; : cure time to 90% of full torque development. : cure time; : scorch time to 2 units of torque increase above minimum torque. CRI: cure rate index: 100/(−).
