Investigation of the ductile deformation potential of microscale epoxy materials

Publikationstyp
Journal Article
Publikationsdatum
2023-09-23
Sprache
English
Author
Mittelhaus, Janina orcid-logo
Kunststoffe und Verbundwerkstoffe M-11 
Röttger, Phil
Schill, Eduard 
Jacobs, Julius
Fiedler, Bodo orcid-logo
Kunststoffe und Verbundwerkstoffe M-11 
Examination Date
2023-09-23
Institute
Kunststoffe und Verbundwerkstoffe M-11 
DOI
10.15480/882.8688
TORE-URI
https://hdl.handle.net/11420/43590
Enthalten in
Polymer testing 
Volume
128
Article Number
108217
Citation
Polymer testing 128: 108217 (2023-09)
Publisher DOI
10.1016/j.polymertesting.2023.108217
Scopus ID
2-s2.0-85172922636
Publisher
Elsevier
In fiber reinforced polymers (FRP), the matrix, e.g. an epoxy system, usually has a microscopic size and therefore may have other properties than the standard bulk samples. It is known that a size effect exists, for epoxy also in terms of ductility or plasticity. However, to date, there is no physical, mechanochemical or molecular explanation for the correlation of plasticity and gauge volume, especially for an archetypical brittle standard epoxy matrix. The specific limits of the gauge volume for these ductile effects are unknown as well. Therefore, a new manufacturing method to produce thin epoxy films with thicknesses between 15 and 100 μm is developed. These films are investigated by differential scanning calorimetry (DSC) with regard to the degree of cross-linking. The mechanical properties are determined by tensile and creep test, also at different temperatures. In the next step, a suitable analysis method for the correlation of molecular structure and mechanical deformation behavior is developed. Manufactured films are investigated by ex situ and in situ infrared spectroscopy (IR) to analyze the molecular mechanisms caused by load introduction. Various pre-processing and interpretation methods for the determination of spectral changes, such as peak shifts, are used to figure out the specific molecular changes related to the mechanical stress from the raw spectral data. It was possible to detect molecular changes of the highly cross-linked macromolecules as a result of plastic deformation caused by tensile load. Shear bands and necking are visualized by photoelastic analysis and a better understanding of the brittle material’s ability to form shear bands is achieved.
Schlagworte
Brittle-to-ductile transition
Infrared spectroscopy
Peak shift
Plasticity
Size effect
Thermomechanical behavior
DDC Class
620: Engineering
Publication version
publishedVersion
Lizenz
https://creativecommons.org/licenses/by/4.0/
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