Evaluation of Stabilizing Additives Content in the Mechanical Properties of Elastomeric Compositions Subject to Environmental and Accelerated Aging

Abstract

This research aimed to evaluate the ideal proportion of two stabilizers in elastomeric compositions indicated for tire sidewall. The stabilizers applied in different proportions were N-1,3-dimethyl-butyl-N'-phenyl-p-phenylenediamine (6PPD) and oligomerized 2,2,4-trimethyl-quinoline (TMQ). Nine compositions were prepared with 0.5, 1.5 and 2.5 phr of 6PPD combined with 0.5, 1.0 and 1.5 phr of TMQ. The compounds were exposed to accelerated aging processes, including thermo-oxidative, photochemical and ozone chamber. Also, the samples were aged in the environment for 440 days. At regular intervals, the samples were evaluated. Gas chromatography was used to quantify the content of 6PPD. Overall, the samples exposed to thermo-oxidative aging showed the greatest loss of mechanical properties (tear and tensile strength) as well as the 6PPD content. From the mechanical strength results, it was possible to conclude that the best combination of stabilizers was 2.5 phr of 6PPD and 1.0 of TMQ.

Widespread N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine Quinone in Size-Fractioned Atmospheric Particles and Dust of Different Indoor Environments

“…Multifarious chemicals serving as additives have been incorporated into synthetic rubber materials to achieve excellent properties, but when released into the environment (e.g., aquatic ecosystems), they can pose adverse threats to biota . The toxicity of road runoff has been attributed to several traditional pollutants from tire leachate, such as vulcanization accelerator benzothiazoles, polycyclic aromatic hydrocarbons, and trace metals. , Rubber antioxidants (or antiaging agents) have emerged as a class of novel pollutants, particularly for p -phenylenediamine (PPD) compounds, , used to resist the degradation and cracking of rubber articles caused by hazardous ozone, high-energy rays, or temperature fluctuations …”

“…3,4 Rubber antioxidants (or antiaging agents) have emerged as a class of novel pollutants, particularly for p-phenylenediamine (PPD) compounds, 5,6 used to resist the degradation and cracking of rubber articles caused by hazardous ozone, high-energy rays, or temperature fluctuations. 7 Among the antioxidants, N-(1,3-dimethylbutyl)-N′-phenylp-phenylenediamine (6-PPD) is the most used species on the market and in Germany is only approved for food contact materials, 8,9 although the relevant toxicity effects were documented. 10 In China, 6-PPD contributed the largest share (∼54%) among all rubbery antioxidants, and its annual output reached 0.2 million tons in 2020.…”

Temperature Dependent Mechanical Properties of Natural and Synthetic Rubber in Practical Structures

“…In case of ageing temperature treatment, the deviations both tire and bearing pad rubber are low because of recovery behaviour of the rubber materials. The higher recovery property makes the lower deviation for bearing pad rubber [11,22].…”

“…Both natural and synthetic rubber requires age resisters for best performance. Protection against oxygen and ozone attack as well as heat and light damage are conferred by antioxidants, antiozonates, ultraviolet light protectors and waxes [11,12]. Damage to rubber by abrasion is combated by the incorporation of fillers like carbon black.…”

Evaluation of lignin as stabilizer in vulcanized natural rubber formulations

“…Oxidative aging in elastomers is one of the most important problems in rubber compound technology because the absorption of a small amount of oxygen causes considerable changes in physical and mechanical properties. These changes can be delayed, but not completely avoided, through the use of a stabilizer [8] . Stabilizers are chemical compounds that inhibit degradative processes in polymers [9] , and generally three factors affect the efficiency of these substances within the NR.…”