Title: Gamma Irradiation and Oxidative Degradation of a Silica-Filled Silicone Elastomer

Abstract

The radiation oxidative degradation of a commonly used silica-filled silicone elastomer DC745 was investigated by a series of experimental techniques. This elastomer is known to be chemically and thermally stable, but insufficient data exist on the radiation resistance. In the present work, gamma doses up to 200 kGy were applied under air at RT and 1Gy/s. Radiation chemical changes were investigated by NMR, FT-IR, Raman, and mass spectroscopy. DSC and TGA experiments probed thermal transitions and thermal stability changes with exposure dose. SEM probed variations on the surface of the elastomer, and solvent swelling methods were used to investigate changes in the polymer network properties. Electron paramagnetic resonance was employed to detect and identify free radicals. Uniaxial compression load tests at variable temperatures were performed to assess changes in the material’s mechanical response as a function of radiation dose. Results demonstrate that, with increasing exposure, DC745 undergoes changes in chemistry that lead to an increase in thermal stability and cross-link density, formation of free radical species, decrease in heat of fusion and increase in stiffness at low temperatures. Taken together, these results indicate that oxidative cross-linking is the dominant radiolysis mechanism that occurs when this material is exposed to gammamore » irradiation in air at high dose rates.« less

Authors:

Labouriau, Andrea ^[1]; Cady, Carl Mcelhinney ^[2]; Gill, John T. ^[1]; Stull, Jamie Ann ^[2]; Ortiz-Acosta, Denisse ^[1]; Henderson, Kevin C. ^[2]; Hartung, Vaughn ^[2]; Quintana, Adam ^[3]; Celina, Mathew C. ^[3]

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemical Diagnostic and Engineering
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Division of Materials Science and Technology
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials Characterization and Performance Dept.

Publication Date:

2015-03-21

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1329567

Alternate Identifier(s):

OSTI ID: 1245280

Report Number(s):

LA-UR-15-21100
Journal ID: ISSN 0141-3910

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Polymer Degradation and Stability

Additional Journal Information:

Journal Volume: 116; Journal ID: ISSN 0141-3910

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; PDMS, irradiation; oxidative degradation; radiolysis