Synergistic Effects of Amine‐Containing Antioxidants on the Aging Performances of Ethylene Propylene Diene Rubber

Abstract

In this study, two types of amine-containing antioxidants composed of 2-mercaptobenzimidazole zinc (MBZ) and 4,4'-bis (α, α-dimethylbenzyl) diphenylamine (445) were used to improve the thermo-oxidative aging resistance of ethylene propylene diene rubber (EPDM). The synergistic effects on the performances of EPDM and the corresponding aging mechanism were investigated by FTIR, tensile test, differential scanning calorimetry (DSC), rotary rheometer and other equipment. The results showed that the hardness increased gradually with the increasing aging time regardless of the type of antioxidants. Compared with the EPDM without antioxidants, the elongation retention of those samples with MBZ or 445 improved obviously. Additionally, the sample with the MBZ/445 complex showed the highest retention values at the same aging time. The antioxidative mechanisms were further analyzed by carbonyl index, activation energy and oxidation induction time, respectively. Results indicated that the degree of oxidation of EPDM using the MBZ/445 complex was much lower than other control systems during the aging process. As a result, the MBZ/445 complex was a favorable antioxidative additive for EPDM.[a] Dr.

Coordinated control study of oil, wax, and antioxidants on tire sidewall rubber discoloration and fatigue properties

“…This result is primarily caused by the weak early anti‐aging effect of the long‐acting antioxidant. Other antioxidants (such as antioxidant 4020) are usually used alongside to boost the anti‐aging effect through the synergistic effect 49–51 . Range analysis shows the effects of different factors on the mechanical properties at 100°C after 24 h. The effect of microcrystalline wax is greater than that of aromatic oil and antioxidant.…”

“…During its service life, the action of mechanical force brought by vehicle load and factors such as light and oxygen in the environment decompose the tire sidewall rubber into rubber molecular chain radicals (R·). These radicals generate peroxide radicals (ROO·) under the action of oxygen or ozone, which further triggers molecular chain breaking and generates rubber peroxide (ROOH) that not only decomposes into rubber oxide radicals (RO·) 51 to continue the breaking of substrate molecular chains but also catalyzes the reaction of rubber molecular chain breaking by generating free radicals, accelerating tire sidewall aging and performance degradation. Long‐term cyclic loading decreases the energy required for the elastomer network at the crack tip to react with ozone and oxygen during usage, increasing their likelihood of reacting with the carbon–carbon double bonds on the main chain and breaking the rubber molecule 54,55 .…”

A new strategy for improving high‐temperature mechanical properties of HNBR/ZDMA composites through polymerization of ZDMA promoted by zinc methylmercaptobenzimidazole

“…This was because that MMBZ consumed some of the alkoxy radicals generated from the peroxide and inhibited PZDMA from grafting onto the HNBR molecular chains. 37…”

“…When the MMBZ content exceeded 8 phr, the T s2 , T 10 , and T 90 were prolonged, while the CRI and M H -M L reduced, which was due to the more consumption of BIBP by excessive MMBZ. 37 Figure 4 shows the effect of the MMBZ content on the crosslinking density of the HNBR/ZDMA-MMBZ composites. With MMBZ content increasing, the covalent crosslinking density (V e1 ) of the HNBR/ZDMA-MMBZ composites remained relatively stable, while the ionic crosslinking density (V e2 ) and total crosslinking density (V e ) increased.…”

On the Use of Oxidation Induction Time as a Kinetic Parameter for Condition Monitoring and Lifetime Evaluation under Ionizing Radiation Environments

“…Among these polymers, the hydrocarbon-based ones (PE, EPR, EVA, and natural and synthetic rubbers) are relatively susceptible to degradation under environmental conditions; therefore, antioxidants and stabilizers are used to suppress the various degradation processes, mainly the oxidative processes, expanding their lifespan [7][8][9]. The presence of an antioxidant within a hydrocarbon polymer matrix can be easily detected by isothermal oxidative tests through thermal analysis methods (DSC, chemiluminescence) when a significantly longer induction period of oxidation is observed compared to the blank (free of antioxidants) polymer.…”