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Abstract: Understanding the underlying processes associated with the thermo-oxidative performance of the ethylene-propylene-diene monomer (EPDM) is essential for assessing and improving its waterproofing performance in underground infrastructures. To explore the fundamentals of EPDM degradation behavior during thermal oxidation, this paper investigates the effects of hydrocarbon free chain, carbon crosslink, chain scission, hydroxyl, and ether crosslinks, on its kinetics and mechanical properties through molecular dynamics (MD) simulations. Several EPDM thermo-oxidative models were built and verified by comparing the simulation results of oxygen diffusivity, glass transition temperature, and mechanical properties with reported experimental ones. Then the radius of gyration, free volume, density, transport, glass transition, and uniaxial compression performance were investigated via MD simulations. The results show that crosslinking in the thermal oxidation process has a significant influence on the free volume, glass transition temperature, and mechanical properties of the system; the hydroxyl and chain scission mainly interfere with the transport properties; all of these affect the structural conformation.

热氧老化对三元乙丙橡胶动力学性能与物理性质的影响

[1]Assink RA, Gillen KT, Sanderson B, 2002. Monitoring the degradation of a thermally aged EPDM terpolymer by ¹H NMR relaxation measurements of solvent swelled samples. Polymer, 43(4):1349-1355.

[2]Banik I, Bhowmick AK, 2000. Effect of electron beam irradiation on the properties of crosslinked rubbers. Radiation Physics and Chemistry, 58(3):293-298.

[3]Bouguedad D, Mekhaldi A, Boubakeur, Ahmed, et al., 2008. Thermal ageing effects on the properties of ethylene-propylene-diene monomer (EPDM). Annales de Chimie (Paris 1914), 33(4):303-313.

[4]Cao H, Gu Z, Chen Z, et al., 2016. Sub-rouse mode relaxation in ethylene-propylene-diene rubber above glass transition. Acta Polymerica Sinica, (9):1206-1211 (in Chinese).

[5]Charati SG, Stern SA, 1998. Diffusion of gases in silicone polymers: molecular dynamics simulations. Macromolecules, 31(16):5529-5535.

[6]Choi SS, Jose J, Lyu MY, et al., 2010. Influence of filler and cure systems on thermal aging resistance of natural rubber vulcanizates under strained condition. Journal of Applied Polymer Science, 118(5):3074-3081.

[7]Colin X, Hassine MB, Nait-Abelaziz M, 2019. Chemo-mechanical model for predicting the lifetime of EPDM rubbers. Rubber Chemistry and Technology, 92(4):722-748.

[8]Cui T, Chao YJ, van Zee JW, 2012. Stress relaxation behavior of EPDM seals in polymer electrolyte membrane fuel cell environment. International Journal of Hydrogen Energy, 37(18):13478-13483.

[9]Delor F, Teissedre G, Baba M, et al., 1998. Ageing of EPDM—2. Role of hydroperoxides in photo-and thermo-oxidation. Polymer Degradation and Stability, 60(2-3):321-331.

[10]Delor-Jestin F, Lacoste J, Barrois-Oudin N, et al., 2000. Photo-, thermal and natural ageing of ethylene–propylene– diene monomer (EPDM) rubber used in automotive applications. Influence of carbon black, crosslinking and stabilizing agents. Polymer Degradation and Stability, 67(3):469-477.

[11]Duek ER, Juliano VF, Guzzo M, et al., 1990. The photo-oxidation of EPDM rubber: part II—the photo-initiation process. Polymer Degradation and Stability, 28(3):235-248.

[12]Ferradino AG, 2003. Antioxidant selection for peroxide cure elastomer applications. Rubber Chemistry and Technology, 76(3):694-718.

[13]Ghasemi M, Morteza SM, 2013. Performance improvement of a crumb rubber modified bitumen using recycled glass powder. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 14(11):805-814.

[14]http://doi.org/10.1631/jzus.A1300053

[15]Gorur RS, Rajan SS, Amburgey OG, 1989. Contamination performance of polymeric insulating materials used for outdoor insulation applications. IEEE Transactions on Electrical Insulation, 24(4):713-716.

[16]Gu Z, Zhang X, Bao C, et al., 2015. Crosslinking-dependent relaxation dynamics in ethylene-propylene-diene (EPDM) terpolymer above the glass transition temperature. Journal of Macromolecular Science, Part B, 54(5):618-627.

[17]Guzzo M, de Paoli MA, 1992. The photo-oxidation of EPDM rubber: part IV—degradation and stabilization of vulcanizates. Polymer Degradation and Stability, 36(2):169-172.

[18]Jiang J, Chen X, Xu JS, et al., 2017. Quasi-static compression mechanical properties of EPDM material after pyrolysis. Journal of Aerospace Power, 32(1):114-119 (in Chinese).

[19]Landi VR, Easterbrook EK, 1978. Scission and crosslinking during oxidation of peroxide cured EPDM. Polymer Engineering and Science, 18(15):1135-1143.

[20]Li RJ, Corripio AB, Henson MA, et al., 2004. On-line state and parameter estimation of EPDM polymerization reactors using a hierarchical extended Kalman filter. Journal of Process Control, 14(8):837-852.

[21]Lim SY, Sahimi M, Tsotsis TT, et al., 2007. Molecular dynamics simulation of diffusion of gases in a carbon-nanotube–polymer composite. Physical Review E, 76(1):011810.

[22]Liu Y, Zhou HB, 2016. Analysis of leakage paths induced by longitudinal differential settlement of the shield-driven tunneling. Proceedings of the 3rd International Conference on Engineering Technology and Application, p.914-919.

[23]Lucas P, Baba M, Lacoste J, et al., 2002. Crosslinking of dienic elastomers resulting from ageing: X-ray diffraction and refractometry measurements. Polymer Degradation and Stability, 76(3):449-453.

[24]Ma LX, Yang G, Tang YZ, 2013. The effect of AIREBO on thermal conductivity of EPDM networks. Key Engineering Materials, 561:164-168.

[25]Madkour TM, 2000. Development of the molecular design rules of ultra-permeable poly [1-(trimethylsilyl)-1-propyne] membranes. Polymer, 41(20):7489-7497.

[26]Moreno VM, Gorur RS, 2001. Effect of long-term corona on non-ceramic outdoor insulator housing materials. IEEE Transactions on Dielectrics and Electrical Insulation, 8(1):117-128.

[27]Parameswaranpillai J, Pulikkalparambil H, Sanjay MR, et al., 2019a. Polypropylene/high-density polyethylene based blends and nanocomposites with improved toughness. Materials Research Express, 6(7):075334.

[28]Parameswaranpillai J, Elamon R, Sanjay MR, et al., 2019b. Synergistic effects of ethylene propylene diene copolymer and carbon nanofiber on the thermo-mechanical properties of polypropylene/high-density polyethylene composites. Materials Research Express, 6(8):085302.

[29]Paroli RM, Dutt O, Delgado AH, et al., 1991. Characterization of ethylene-propylene-diene monomer (EPDM) roofing membranes using thermogravimetry and dynamic mechanical analysis. Thermochimica Acta, 182(2):303-317.

[30]Redline EM, Celina MC, Harris CE, et al., 2017. Anomalous aging of EPDM and FEPM under combined thermo-oxidative and hydrolytic conditions. Polymer Degradation and Stability, 146:317-326.

[31]Rivaton A, Cambon S, Gardette JL, 2004. Radiochemical aging of ethylene–propylene–diene monomer elastomers. I. Mechanism of degradation under inert atmosphere. Journal of Polymer Science Part A: Polymer Chemistry, 42(5):1239-1248.

[32]Rivaton A, Cambon S, Gardette JL, 2006. Radiochemical ageing of ethylene–propylene–diene elastomers. 4. Evaluation of some anti-oxidants. Polymer Degradation and Stability, 91(1):136-143.

[33]Rutherford SW, Limmer DT, Smith MG, et al., 2007. Gas transport in ethylene–propylene–diene (EPDM) elastomer: molecular simulation and experimental study. Polymer, 48(22):6719-6727.

[34]Schurch M, 2006. Small but important–gasket for tunnel segments. Proceedings of the International Symposium on Underground Excavation and Tunnelling, p.239-248.

[35]Scoponi M, Pradella F, Carassiti V, et al., 1994. Photodegradation of poly [ethylene-co-propene-co-(5-ethylidene-2-norbornene)] rubbers, 1. Reappraisal of the photo-oxidation mechanism under accelerated conditions. Macromolecular Chemistry and Physics, 195(3):985-997.

[36]Teissedre G, Pilichowski JF, Chmela S, et al., 1996. Ageing of EPDM—I: photo and thermal stability of EPDM hydroperoxides. Polymer Degradation and Stability, 53(2):207-215.

[37]Tomer NS, Delor-Jestin F, Singh RP, et al., 2007. Cross-linking assessment after accelerated ageing of ethylene propylene diene monomer rubber. Polymer Degradation and Stability, 92(3):457-463.

[38]Wang WW, Tanaka Y, Takada T, et al., 2018. Influence of oxidation on the dynamics in amorphous ethylene-propylene-diene-monomer copolymer: a molecular dynamics simulation. Polymer Degradation and Stability, 147:187-196.

[39]Wang WZ, Qu BJ, 2003. Photo- and thermo-oxidative degradation of photocrosslinked ethylene–propylene–diene terpolymer. Polymer Degradation and Stability, 81(3):531-537.

[40]Wang YH, Yang G, Wang WH, et al., 2019. Effects of different functional groups in graphene nanofiber on the mechanical property of polyvinyl alcohol composites by the molecular dynamic simulations. Journal of Molecular Liquids, 277:261-268.

[41]Wang YJ, Yang YY, Tao MJ, 2019. Understanding free volume characteristics of ethylene-propylene-diene monomer (EPDM) through molecular dynamics simulations. Materials, 12(4):612.

[42]Wu CF, Xu WJ, 2006. Atomistic molecular modelling of crosslinked epoxy resin. Polymer, 47(16):6004-6009.

[43]Wu CF, Xu WJ, 2007. Atomistic simulation study of absorbed water influence on structure and properties of crosslinked epoxy resin. Polymer, 48(18):5440-5448.

[44]Wu HN, Huang RQ, Sun WJ, et al., 2014. Leaking behavior of shield tunnels under the Huangpu river of Shanghai with induced hazards. Natural Hazards, 70(2):1115-1132.

[45]Zachary M, Camara S, Whitwood AC, et al., 2008. EPR study of persistent free radicals in cross-linked EPDM rubbers. European Polymer Journal, 44(7):2099-2107.