Challenges of accelerated aging techniques for elastomer lifetime predictions

Journal Article · Sun Mar 01 00:00:00 EST 2015 · Rubber Chemistry and Technology

DOI:https://doi.org/10.5254/rct.14.85930· OSTI ID:1361646

Gillen, Kenneth T. ^[1]; Bernstein, R. ^[1]; Celina, M. ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Elastomers are often degraded when exposed to air or high humidity for extended times (years to decades). Lifetime estimates normally involve extrapolating accelerated aging results made at higher than ambient environments. Several potential problems associated with such studies are reviewed, and experimental and theoretical methods to address them are provided. The importance of verifying time–temperature superposition of degradation data is emphasized as evidence that the overall nature of the degradation process remains unchanged versus acceleration temperature. The confounding effects that occur when diffusion-limited oxidation (DLO) contributes under accelerated conditions are described, and it is shown that the DLO magnitude can be modeled by measurements or estimates of the oxygen permeability coefficient (P_Ox) and oxygen consumption rate (Φ). P_Ox and Φ measurements can be influenced by DLO, and it is demonstrated how confident values can be derived. In addition, several experimental profiling techniques that screen for DLO effects are discussed. Values of Φ taken from high temperature to temperatures approaching ambient can be used to more confidently extrapolate accelerated aging results for air-aged materials, and many studies now show that Arrhenius extrapolations bend to lower activation energies as aging temperatures are lowered. Furthermore, best approaches for accelerated aging extrapolations of humidity-exposed materials are also offered.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1361646
• Report Number(s): SAND-2017-0624J; 650587
• Journal Information: Rubber Chemistry and Technology, Vol. 88, Issue 1; ISSN 0035-9475
• Publisher: American Chemical Society (ACS), Rubber Division
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY