Insights for lifetime predictions of O-ring seals from five-year long-term aging tests

Kömmling, Anja; Jaunich, Matthias; Goral, Milan; Wolff, Dietmar

doi:10.1016/j.polymdegradstab.2020.109278

Cited by 38 publications

(47 citation statements)

References 36 publications

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“…This is probably due to the lower values of CS after tempering. Even for samples aged at 75 • C for five years, CS did not exceed 14% [36]. Figure 7 presents the normalized continuous stress relaxation R c with two first order chemical relaxation processes.…”

Section: Fe Simulation Resultsmentioning

confidence: 99%

“…This is probably due to the lower values of CS after tempering. Even for samples aged at 75 °C for five years, CS did not exceed 14% [ 36 ].…”

Section: Resultsmentioning

confidence: 99%

“…But it is valid only when the degradative ageing of the material is homogeneous, i.e., free of DLO effects [ 13 ]. Previously, intender modulus measurements were carried out on the surface layers of aged EPDM O-ring surfaces in uncompressed as well as in compressed state by 25%, with the same material compound and geometry [ 16 , 34 , 36 , 48 ]. The samples aged at 150 °C age homogeneously until 101 days (which corresponds to R c = 0.06 from the experimental results, see Figure 1 ); as for these samples, no heterogeneous hardening was observed [ 16 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

“…It is to mention that the thermal decomposition of the deformation gradient

is beyond the scope of the present modeling, since the experiments were performed under isothermal conditions, and no ageing-induced volume change is considered. Moreover, as the imposed deformation according to the experiments is set to 25%, no deformation induced scission is taken into account in the present modeling, as our comparison between the effect of compressed and uncompressed ageing did not indicate differences between the samples [ 36 ]. However, deformation combined with temperature could affect scission in special cases where the deformation in tension exceeds 200%, as has been reported in the literature [ 20 , 37 ].…”

Section: Modelingmentioning

confidence: 99%

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Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing

et al. 2020

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To improve the predictive capability of long-term stress relaxation of elastomers during thermo-oxidative ageing, a method to separate reversible and irreversible processes was adopted. The separation is performed through the analysis of compression set after tempering. On the basis of this separation, a numerical model for long-term stress relaxation during homogeneous ageing is proposed. The model consists of an additive contribution of physical and chemical relaxation. Computer simulations of compression stress relaxation were performed for long ageing times and the results were validated with the Arrhenius treatment, the kinetic study and the time-temperature superposition technique based on experimental data. For chemical relaxation, two decay functions are introduced each with an activation energy and a degradative process. The first process with the lower activation energy dominates at lower ageing times, while the second one with the higher activation energy at longer ageing times. A degradation-rate based model for the evolution of each process and its contribution to the total system during homogeneous ageing is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing a straight-line extrapolation.

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Section: Fe Simulation Resultsmentioning

confidence: 99%

“…This is probably due to the lower values of CS after tempering. Even for samples aged at 75 °C for five years, CS did not exceed 14% [ 36 ].…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…It is to mention that the thermal decomposition of the deformation gradient

Section: Modelingmentioning

confidence: 99%

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Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing

et al. 2020

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“…Electronics rubbers generally have some good and poor properties, and their good properties are due to their stable backbone structure and are the main factors that prompted the initial interest for the use of rubber in electronics. For instance, Carbon Nanotubes as Reinforcing Nanomaterials for Rubbers Used in Electronics DOI: http://dx.doi.org/10.5772/intechopen.94061 rubbers like NBR, EPDM and FKM are known to have high lifetime or life expectancy, with FKM having relatively the highest, as it has been shown by their hardness and compression set properties which were studied on their O-ring seals after aging for five-years at various temperatures [14]. With the current transition from CB to CNTs due to superior properties and performances of the latter relative to the former, literature has reported that rubber-CNTs composites are currently the major application area for CNTs in the reinforcement of rubbers.…”

Section: Overview Of Rubber-cnts Composites For Electronicsmentioning

confidence: 99%

Carbon Nanotubes as Reinforcing Nanomaterials for Rubbers Used in Electronics

Gumede¹,

Carson²,

Hlangothi³

2021

Carbon Nanotubes - Redefining the World of Electronics

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The field of electronics involves complex systems where the active and passive electronic devices are integrated on the rubber substrate, e.g., silicone (Q), which provides, through potting, a strong assembly of these devices on the circuit board. Several other rubbers are employed in the field to strengthen, insulate and seal the components of the electronic machines and instruments, and therefore protect them against damage. These rubbers are typically strengthened and toughened using carbon black (CB). However, due to its noticeable drawbacks, recent research in the field of rubber and electronics has suggested the use of carbon nanotubes (CNTs) as alternative reinforcing fillers to produce electronics rubber composites that do not only have enhanced electrical conductiv¬ity, thermal stability, electromagnetic interference (EMI) shielding, weatherability and insulation properties, but also offer outstanding stretchability, bendability and tear strength under frequent elastic deformation. These performances are similar for both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in both the functional and structural composites. Although SWCNTs can result in relatively better homogeneity than MWCNTs, most rubbers often constitute MWCNTs because they are relatively cheaper. The great potential of rubber-CNTs composites being extensively used in the field of electronics is explored in this chapter.

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Service lifetime prediction of nitrile butadiene rubber gaskets used in plate heat exchangers

Zanzi

Souza

Dutra

et al. 2022

J of Applied Polymer Sci

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Gasketed plate heat exchangers are characterized in a usual heat exchanger class. These systems employ elastomeric gaskets as the sealing element. Several conditions lead to oxidation and deterioration of these materials and their properties. In addition, the complex geometry of the gaskets and operation conditions may cause divergence in the expected aging behavior of the rubber. In light of this, this study aims to predict the service lifetime for nitrile butadiene rubber gaskets used in plate heat exchangers based on their geometry under thermo‐oxidative aging. These gaskets were evaluated by means of Shore A hardness, compression set (CS), and indentation modulus profile. Through aging‐sealing tests, an end‐of‐life criteria was determined concerning CS measurements and the service lifetime prediction was obtained by time–temperature superposition and WLF method. Diffusion‐limited oxidation effects were observed at high temperatures in postaging analysis and a non‐Arrhenius behavior was observed at 170°C. The value of 79% CS was obtained as end‐of‐life criteria from 60 to 140°C, ranged from 731 to 80 days, respectively, revealing an activation energy equivalent to 32.3 kJ mol−1. These results might support the maintenance planning control of gasketed plate heat exchangers.

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Insights for lifetime predictions of O-ring seals from five-year long-term aging tests

Cited by 38 publications

References 36 publications

Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing

Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing

Carbon Nanotubes as Reinforcing Nanomaterials for Rubbers Used in Electronics

Service lifetime prediction of nitrile butadiene rubber gaskets used in plate heat exchangers

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