Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites
Epoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins and their carb...
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| Format: | Article |
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MDPI AG
2023-01-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/3/725 |
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| author | Baoming Wang Shengzong Ci Mingzhe Zhou Chengrui Di Junwei Yu Bo Zhu Kun Qiao |
| author_facet | Baoming Wang Shengzong Ci Mingzhe Zhou Chengrui Di Junwei Yu Bo Zhu Kun Qiao |
| author_sort | Baoming Wang |
| collection | DOAJ |
| description | Epoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins and their carbon fibre composites was carried out via artificially accelerated experiments under hygrothermal and salt mist conditions. The moisture penetration along the depth, water absorption, appearance, hardness, density of the epoxy resins, and variation patterns of the impact strength and tensile strength of the epoxy-based composites were investigated. The ageing mechanisms were explored using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both ageing modes had essentially similar influences on the properties of the resins and their composites; moreover, they did not significantly affect the chemical structure and microstructure of the epoxy resin, with the physical adsorption of water primarily observed during the ageing process. The moisture absorption behaviour of the epoxy obeyed Fick’s law. Although the water penetration rate in the salt mist ageing mode was slightly higher than that in the hygrothermal ageing mode during the early ageing stage, it was essentially the same during the later stage. The final moisture absorption rate at saturation was approximately 1.1% under both modes. The flexural strengths and impact strengths of the composites in both ageing modes followed a similar trend. They decreased gradually with the ageing time and then stabilized at almost the same value. The flexural strength was reduced from 803 MPa to 760 MPa and the impact strength from 383 J/m<sup>2</sup> to 310 J/m<sup>2</sup>, indicating a decrease of approximately 5.4% and 19%, respectively. The absorbed water during the ageing process caused micro-cracks at the interface between the fibres and resin, weakening the interfacial strength and reducing the mechanical properties of the composites. |
| first_indexed | 2024-03-11T09:28:49Z |
| format | Article |
| id | doaj.art-c97d8fece74041a8b5db74af2848f08a |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T09:28:49Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-c97d8fece74041a8b5db74af2848f08a2023-11-16T17:49:41ZengMDPI AGPolymers2073-43602023-01-0115372510.3390/polym15030725Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their CompositesBaoming Wang0Shengzong Ci1Mingzhe Zhou2Chengrui Di3Junwei Yu4Bo Zhu5Kun Qiao6School of Materials Science and Engineering, Shandong University, Jinan 250012, ChinaSchool of Electromechanical and Information Engineering, Shandong University, Weihai 264209, ChinaSchool of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UKSchool of Electromechanical and Information Engineering, Shandong University, Weihai 264209, ChinaSchool of Materials Science and Engineering, Shandong University, Jinan 250012, ChinaSchool of Materials Science and Engineering, Shandong University, Jinan 250012, ChinaSchool of Electromechanical and Information Engineering, Shandong University, Weihai 264209, ChinaEpoxy and epoxide composites have a wide range of outdoor applications wherein they are affected by ageing. In this study, epoxy casting plates and epoxy-based composite rods for use in overhead conductors were prepared. A concurrent investigation concerning the ageing of epoxy resins and their carbon fibre composites was carried out via artificially accelerated experiments under hygrothermal and salt mist conditions. The moisture penetration along the depth, water absorption, appearance, hardness, density of the epoxy resins, and variation patterns of the impact strength and tensile strength of the epoxy-based composites were investigated. The ageing mechanisms were explored using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Both ageing modes had essentially similar influences on the properties of the resins and their composites; moreover, they did not significantly affect the chemical structure and microstructure of the epoxy resin, with the physical adsorption of water primarily observed during the ageing process. The moisture absorption behaviour of the epoxy obeyed Fick’s law. Although the water penetration rate in the salt mist ageing mode was slightly higher than that in the hygrothermal ageing mode during the early ageing stage, it was essentially the same during the later stage. The final moisture absorption rate at saturation was approximately 1.1% under both modes. The flexural strengths and impact strengths of the composites in both ageing modes followed a similar trend. They decreased gradually with the ageing time and then stabilized at almost the same value. The flexural strength was reduced from 803 MPa to 760 MPa and the impact strength from 383 J/m<sup>2</sup> to 310 J/m<sup>2</sup>, indicating a decrease of approximately 5.4% and 19%, respectively. The absorbed water during the ageing process caused micro-cracks at the interface between the fibres and resin, weakening the interfacial strength and reducing the mechanical properties of the composites.https://www.mdpi.com/2073-4360/15/3/725polymer-matrix composites (PMCs)environmental degradationmoisturepultrusionmoisture absorption |
| spellingShingle | Baoming Wang Shengzong Ci Mingzhe Zhou Chengrui Di Junwei Yu Bo Zhu Kun Qiao Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites Polymers polymer-matrix composites (PMCs) environmental degradation moisture pultrusion moisture absorption |
| title | Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites |
| title_full | Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites |
| title_fullStr | Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites |
| title_full_unstemmed | Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites |
| title_short | Effects of Hygrothermal and Salt Mist Ageing on the Properties of Epoxy Resins and Their Composites |
| title_sort | effects of hygrothermal and salt mist ageing on the properties of epoxy resins and their composites |
| topic | polymer-matrix composites (PMCs) environmental degradation moisture pultrusion moisture absorption |
| url | https://www.mdpi.com/2073-4360/15/3/725 |
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