Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Ferrari, Matteo; Pandini, Stefano; Zenoni, A.; Donzella, Giorgio; Battini, Davide; Avanzini, Andrea; Salvini, Andrea; Zelaschi, F.; Andrighetto, A.; Bignotti, Fabio

doi:10.1002/pen.25249

Cited by 6 publications

(6 citation statements)

References 30 publications

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“…The mechanical properties of these studied samples are tightly related to the level of γ-irradiation [43], whose values are the combination between this scission process and a certain degree of crosslinking [65]. The illustration of this overlapping is based on the extended durability that occurs in nuclear power plants [40,66].…”

Section: Mechanical Testingmentioning

confidence: 99%

The Contribution of BaTiO3 to the Stability Improvement of Ethylene–Propylene–Diene Rubber: Part I—Pristine Filler

Borbáth¹,

Nicula²,

Zaharescu³

et al. 2023

Polymers

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This study presents the functional effects of BaTiO3 powder loaded in ethylene–propylene–diene rubber (EPDM) in three concentrations: 0, 1, and 2.5 phr. The characterization of mechanical properties, oxidation strength, and biological vulnerability is achieved on these materials subjected to an accelerated degradation stimulated by their γ-irradiation at 50 and 100 kGy. The thermal performances of these materials are improved when the content of filler becomes higher. The results obtained by chemiluminescence, FTIR-ATR, and mechanical testing indicate that the loading of 2.5 phr is the most proper composition that resists for a long time after it is γ-irradiated at a high dose. If the oxidation starts at 176 °C in the pristine polymer, it becomes significant at 188 and 210 °C in the case of composites containing 1 and 2.5 phr of filler, respectively. The radiation treatment induces a significant stability improvement measured by the enlargement of temperature range by more than 1.5 times, which explains the durability growth for the radiation-processed studied composites. The extension of the stability period is also based on the interaction between degrading polymer substrate and particle surface in the composite richest in titanate fraction when the exposure is 100 kGy was analyzed. The mechanical testing as well as the FTIR investigation clearly delimits the positive effects of carbon black on the functionality of EPDM/BaTiO3 composites. The contribution of carbon black is a defining feature of the studied composites based on the nucleation of the host matrix by which the polymer properties are effectively ameliorated.

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Section: Mechanical Testingmentioning

confidence: 99%

The Contribution of BaTiO3 to the Stability Improvement of Ethylene–Propylene–Diene Rubber: Part I—Pristine Filler

Borbáth¹,

Nicula²,

Zaharescu³

et al. 2023

Polymers

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“…EPDM is usually synthesized by solution polymerization technique in a continuous process. Several additives in the form of antioxidants [14], vulcanizing agents [15], accelerators [16], reinforcing agents [17], activators [18], and processing aids [19] are also mixed to improve its inherent properties. To reinforce [20] the EPDM matrix, carbon black or silica are added as ller or grafted by means of entanglement among polymeric chain structure as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Lone and Combine Effect of Accelerated Irradiation and Thermal Aging Stressors on Silica Reinforced Ethylenepropylenediene Monomer Rubber

Naz,

Waqas,

Ahmed

et al. 2024

Preprint

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The aim of this study was to determine the affect of irradiation and thermal accelerated aging (i.e. equivalent to 8years) on Ethylenepropylenediene Monomer (EPDM) rubber contained silica as a filler and also grafted in polymeric matrix. For this purpose, accelerated thermal aging was performed at T = 123°C for 15 days. Whereas, accelerated i.e. short term irradiation aging was done separately under thermal neutron flux in research reactor for 3.6 hrs. The combine affect of thermal aging before and after irradiation was also studied. The results revealed that irradiation promoted crosslinking in EPDM rubber, while thermal aging preferably induced secissioning in silica grafted network chain structure. The further study revealed that irradiation after thermal aging have a propensity to cure the adverse effects of temperature by increase of crosslink density and elimination of pores which made the polymeric matrix more dense as observed by structural (XRD, pole density, FTIR) and microscopic (SEM) Analyses. However, in converse order i.e. thermal aging after irradiation aggravated detrimental effects on EPDM rubber due to prevailing scissioning over crosslinking in polymeric chain structure.

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“…EPDM had the highest irradiation resistance, which depended on the material’s inorganic content. Battini et al [ 14 ] and Ferrari et al [ 15 ] conducted several studies on the degradation of EPDM elastomers irradiated at high dose rates in mixed neutron and gamma fields and found that material degradation was mainly influenced by the total absorbed dose as opposed to the irradiation type and irradiation dosage.…”

Section: Introductionmentioning

confidence: 99%

A Leakage Prediction Model for Sealing Performance Assessment of EPDM O-Rings under Irradiation Conditions

Huang

et al. 2023

Polymers

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In this work, a model for predicting the leakage rate was developed to investigate the effect of irradiation on the sealing performance of ethylene propylene diene monomer (EPDM) O-rings. The model is based on a mesoscopic interfacial gap flow simulation and accurately predicts the sealing performance of irradiated and non-irradiated materials by utilizing the gap height as an indicator in a mechanical simulation of the O-ring under operating conditions. A comparison with vacuum test results indicates that the model is a good predictor of leak initiation. The positive pressure leakage of the O-rings was investigated numerically. The results show the following. The sealing performance of the non-irradiated O-ring is much better than that of the irradiated one. The sealing performance is the worst at 0. 713 MGy and the best at 1.43 MGy, and the seal is maintained at an absorbed dose of 3.55 MGy. A theoretical analysis of the non-monotonic variation using the proposed model shows that the leakage behavior of the O-rings depends not only on the material properties but also on the roughness and prestressing properties. Finally, a method was proposed to classify the sealing performance, using the maximum allowable leakage rate as an indicator.

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Degradation of EPDM and FPM elastomers irradiated at very high dose rates in mixed gamma and neutron fields

Cited by 6 publications

References 30 publications

The Contribution of BaTiO3 to the Stability Improvement of Ethylene–Propylene–Diene Rubber: Part I—Pristine Filler

The Contribution of BaTiO3 to the Stability Improvement of Ethylene–Propylene–Diene Rubber: Part I—Pristine Filler

Lone and Combine Effect of Accelerated Irradiation and Thermal Aging Stressors on Silica Reinforced Ethylenepropylenediene Monomer Rubber

A Leakage Prediction Model for Sealing Performance Assessment of EPDM O-Rings under Irradiation Conditions

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