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Title: Thermal stability of poly(ethylene-co-vinyl acetate) based materials

The thermal stability properties of poly (ethylene-co-vinyl acetate) composites have been studied in support of our core programmes in materials qualification and life assessment. The material is used as a binder phase for boron particles in highly filled (70 wt %) composites. Our studies show that the uncured resin readily accumulates acetic acid through hydrolysis of the pendent acetate groups which alters the acidity (pH) of the material. Thermal desorption studies in combination with gas-chromatography-mass spectrometry show that the resin readily evolves acetic acid when thermally aged to temperatures up to 75°C. Gel Permeation Chromatography (GPC) suggests that thermal ageing induces a gradual reduction in resin molecular weight and confirms the susceptibility of the material to chain scission. Heating at elevated temperatures in excess of 300oC is required to induce significant changes in the carbon skeleton through deacetylation and dehydration processes and the production of unsaturated main chain double bonds. Overall, the mechanical response of these filled composites are found to be relatively complex with the extent of polymer-filler interactions possibly playing an important role in determining key engineering properties. Mechanical property studies confirm a small but significant decrease in modulus presumably linked to thermally induced chain scission of themore » EVA binder.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Atomic Weapons Establishment (AWE), Reading (United Kingdom)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1240064
Report Number(s):
LLNL-JRNL--607753
Journal ID: ISSN 0142-9418
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Polymer Testing
Additional Journal Information:
Journal Volume: 32; Journal Issue: 4; Journal ID: ISSN 0142-9418
Publisher:
Elsevier
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Characterisation; thermal stability; Poly (ethylene-co-vinyl acetate)