Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation
Environmental stress cracking (ESC) is one of the most prominent failure mechanisms for polymer components. The high sensitivity of plastics in regard to environmental influences has always meant that plastics as materials have been viewed very critically in outdoor applications. Recently, the massi...
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MDPI AG
2022-06-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/15/12/4114 |
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| author | Tobias Bubmann Simon Shi Alexander Brueckner Teresa Menzel Holger Ruckdäschel Alois K. Schlarb Volker Altstädt |
| author_facet | Tobias Bubmann Simon Shi Alexander Brueckner Teresa Menzel Holger Ruckdäschel Alois K. Schlarb Volker Altstädt |
| author_sort | Tobias Bubmann |
| collection | DOAJ |
| description | Environmental stress cracking (ESC) is one of the most prominent failure mechanisms for polymer components. The high sensitivity of plastics in regard to environmental influences has always meant that plastics as materials have been viewed very critically in outdoor applications. Recently, the massive occurrence of microplastics in the environment means that questions about the long-term stability of plastic parts and the studies of plastic fragmentation are of great scientific interest. ESC behavior also plays an important role in connection with the formation of microplastics. In this work, the influence of two different sample wetting methods on ESC behavior was investigated. In case A, the sample was in situ wetted with the medium during the measurement by using a sponge. In case B, the sample was wetted by storage in the medium prior to measurement. Different stress cracking agents (SCA) were examined for polymethylmethacrylate (PMMA). Fracture-mechanical fatigue crack propagation (FCP) tests were carried out to quantitatively determine the sensitivity to ESC. Correlations between the absorption behavior and the ESC behavior of the SCA and the resulting morphological phenomena were established. Depending on the wetting method, significant differences in FCP were observed. The in situ wetting of the samples (case A) during the FCP measurement with ethylene glycol (EG) and with deionized water (DI) led to a significant shift in the crack propagation curves to higher ∆K—compared to the PMMA reference. In the case of n-heptane (NH), a more brittle crack propagation behavior was observed due to the chemical interaction with PMMA. The previously immersed samples (case B) give different results. Storage in NH and EG showed no influence on the crack propagation behavior. Samples immersed in DI showed a completely different course of crack growth. At a certain load, a sudden deceleration of the crack propagation and thus a horizontal curve could be seen. Above a certain ∆K value, crack growth began again. Depending on the immersion time (14, 30, or 60 days), this so-called stepped behavior shifted to lower da/dN values. |
| first_indexed | 2024-03-09T23:11:32Z |
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| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T23:11:32Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-33bff7f4137f43cd86b22b40b2fdbf7f2023-11-23T17:42:50ZengMDPI AGMaterials1996-19442022-06-011512411410.3390/ma15124114Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack PropagationTobias Bubmann0Simon Shi1Alexander Brueckner2Teresa Menzel3Holger Ruckdäschel4Alois K. Schlarb5Volker Altstädt6Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, GermanyChair of Composite Engineering (CCe), Technische Universität Kaiserslautern (TUK), 67663 Kaiserslautern, GermanyDepartment of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, GermanyDepartment of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, GermanyDepartment of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, GermanyChair of Composite Engineering (CCe), Technische Universität Kaiserslautern (TUK), 67663 Kaiserslautern, GermanyDepartment of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, GermanyEnvironmental stress cracking (ESC) is one of the most prominent failure mechanisms for polymer components. The high sensitivity of plastics in regard to environmental influences has always meant that plastics as materials have been viewed very critically in outdoor applications. Recently, the massive occurrence of microplastics in the environment means that questions about the long-term stability of plastic parts and the studies of plastic fragmentation are of great scientific interest. ESC behavior also plays an important role in connection with the formation of microplastics. In this work, the influence of two different sample wetting methods on ESC behavior was investigated. In case A, the sample was in situ wetted with the medium during the measurement by using a sponge. In case B, the sample was wetted by storage in the medium prior to measurement. Different stress cracking agents (SCA) were examined for polymethylmethacrylate (PMMA). Fracture-mechanical fatigue crack propagation (FCP) tests were carried out to quantitatively determine the sensitivity to ESC. Correlations between the absorption behavior and the ESC behavior of the SCA and the resulting morphological phenomena were established. Depending on the wetting method, significant differences in FCP were observed. The in situ wetting of the samples (case A) during the FCP measurement with ethylene glycol (EG) and with deionized water (DI) led to a significant shift in the crack propagation curves to higher ∆K—compared to the PMMA reference. In the case of n-heptane (NH), a more brittle crack propagation behavior was observed due to the chemical interaction with PMMA. The previously immersed samples (case B) give different results. Storage in NH and EG showed no influence on the crack propagation behavior. Samples immersed in DI showed a completely different course of crack growth. At a certain load, a sudden deceleration of the crack propagation and thus a horizontal curve could be seen. Above a certain ∆K value, crack growth began again. Depending on the immersion time (14, 30, or 60 days), this so-called stepped behavior shifted to lower da/dN values.https://www.mdpi.com/1996-1944/15/12/4114PMMAenvironmental stress crackingfatiguestress cracking agentda/dNfatigue crack growth |
| spellingShingle | Tobias Bubmann Simon Shi Alexander Brueckner Teresa Menzel Holger Ruckdäschel Alois K. Schlarb Volker Altstädt Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation Materials PMMA environmental stress cracking fatigue stress cracking agent da/dN fatigue crack growth |
| title | Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation |
| title_full | Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation |
| title_fullStr | Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation |
| title_full_unstemmed | Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation |
| title_short | Influence of Sample Wetting Method on ESC-Behavior of PMMA under Dynamic Fatigue Crack Propagation |
| title_sort | influence of sample wetting method on esc behavior of pmma under dynamic fatigue crack propagation |
| topic | PMMA environmental stress cracking fatigue stress cracking agent da/dN fatigue crack growth |
| url | https://www.mdpi.com/1996-1944/15/12/4114 |
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