Chain dynamics evolution of ethylene‐propylene‐diene monomer in response to hot humid and salt fog environment

Abstract

This work is dedicated to the mechanism underlying the influence of the harsh environment that may cause accelerated aging (high temperature, humidity, and salt spray) on the static and dynamics characteristics of ethylene‐propylene‐diene monomer (EPDM) copolymer. A molecular dynamics simulation was employed to provide an insight into the effects of the hot humid and salt fog environment on the micro and macroscopic properties. First, evidence shows that the Tg obtained by fitting mean square displacement does not rely on the selection of the equilibrium time. Second, radial distribution function, chain configuration, and nonbonding interaction were analyzed and it is inferred that the ambient humidity and temperature show a significant synergy on the EPDM system, which is attributed to the aggregation state transition and diffusion behavior of partial water at high temperatures. Finally, water and salt were considered as two factors to explore the influence on the Tg and the mobility of the molecular chain. It is concluded that the existence of water molecules significantly affects the chain dynamic behavior of EPDM, while salt is not regarded as an influencing factor. In general, our simulated work provides some insights and guidance for the durability of EPDM when used in harsh environments.

Performance of Thermal-Oxidative Aging on the Structure and Properties of Ethylene Propylene Diene Monomer (EPDM) Vulcanizates

“…EPDM rubber has been studied in thermal oxygen aging [8][9][10][11], photo-oxygen aging [12,13], artificial weathering aging [14], radiation aging [15,16], and medium aging [17,18] Its research methods and characterization methods are diverse, such as dynamic mechan ical property analysis, spectral analysis (Fourier infrared spectroscopy, Raman spectros copy), energy spectrum analysis (X-ray electron spectroscopy, nuclear magnetic reso nance), and thermal analysis (differential scanning calorimetry, thermogravimetric anal ysis), etc. However, most of them are limited to the research of EPM and EPDM rubber The research on the thermal oxygen aging of EPDM vulcanizates with antioxidant conten and semi-efficient vulcanization system is few.…”

Performance of Thermal-Oxidative Aging on the Structure and Properties of Ethylene Propylene Diene Monomer (EPDM) Vulcanizates

“…EPDM rubber has been studied in thermal-oxygen aging [8,9,10,11,12], photo-oxygen aging [13,14], artificial weathering aging [15], radiation aging [16,17] and medium aging [18,19]. Its research methods and test and characterization methods are diverse, such as dynamic mechanical property analysis, spectral analysis (Fourier infrared spectroscopy, Raman spectroscopy), energy spectrum analysis (X-ray electron spectroscopy, nuclear magnetic resonance), and thermal analysis (differential scanning calorimetry, thermogravimetric analysis), etc.…”

Fully Atomistic Molecular Dynamics Simulation of the Structure and Morphology of Small‐Molecular Additives in Rubber Matrices

“…They belong to the bonding interactions, while the last two terms are the van der Waals interaction term E vdW and the Kuhn interaction term E ele , which belong to the nonbond interactions. [5,27,28] All the molecular simulations in this study were operated on Materials Studio 2019. The repeat units and 3D structures of the three rubbers are shown in Figure 1, and the composition ratios of each repeat unit are shown in Table 1.…”