Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride
Abstract Bio‐based alternatives for petroleum‐based epoxy resin curing agents, such as maleopimaric acid (MPA), are indispensable for sustainable fiber reinforced polymer composites with thermosetting matrices. However, previous investigations disregarded the importance of choosing the right stoichi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2023-11-01
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| Series: | Macromolecular Materials and Engineering |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/mame.202300122 |
| _version_ | 1797627927627563008 |
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| author | Florian Rothenhäusler Marcel Kettenbach Holger Ruckdaeschel |
| author_facet | Florian Rothenhäusler Marcel Kettenbach Holger Ruckdaeschel |
| author_sort | Florian Rothenhäusler |
| collection | DOAJ |
| description | Abstract Bio‐based alternatives for petroleum‐based epoxy resin curing agents, such as maleopimaric acid (MPA), are indispensable for sustainable fiber reinforced polymer composites with thermosetting matrices. However, previous investigations disregarded the importance of choosing the right stoichiometric ratio R between the anhydride groups in the rosin‐based curing agent and the epoxy groups in the resin. Therefore, the influence of R on the curing kinetics and mechanical properties of an epoxy resin cured with a rosin‐based anhydride is studied. Here, Fourier‐transform infrared spectroscopy (FT–IR) indicates that for R ⩾ 0.9 unreacted anhydride groups are present in the thermoset. Consequently, the network density decreases and the glass transition temperature Tg drops by about 40 °C. On the other hand, the steric hindrance of unreacted functional groups for R ⩾ 0.9, increases the flexural modulus and the reduced network density improves fracture toughness. The results indicate that the best R for overall high mechanical performance and good processability is preferably low (R ⩽ 0.7). Here, a low R results in a high Tg and good processability due to a low viscosity. However, the latency of the mixtures is low and therefore, the mixtures are not fit for processing via prepreg technology. |
| first_indexed | 2024-03-11T10:31:25Z |
| format | Article |
| id | doaj.art-2a810f44be2f49739d390385db4c2567 |
| institution | Directory Open Access Journal |
| issn | 1438-7492 1439-2054 |
| language | English |
| last_indexed | 2024-03-11T10:31:25Z |
| publishDate | 2023-11-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Macromolecular Materials and Engineering |
| spelling | doaj.art-2a810f44be2f49739d390385db4c25672023-11-14T16:49:29ZengWiley-VCHMacromolecular Materials and Engineering1438-74921439-20542023-11-0130811n/an/a10.1002/mame.202300122Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based AnhydrideFlorian Rothenhäusler0Marcel Kettenbach1Holger Ruckdaeschel2Department of Polymer Engineering University of Bayreuth Universitätsstraße 30 95447 Bayreuth GermanyDepartment of Polymer Engineering University of Bayreuth Universitätsstraße 30 95447 Bayreuth GermanyNeue Materialien Bayreuth GmbH Gottlieb‐Keim‐Straße 60 95448 Bayreuth GermanyAbstract Bio‐based alternatives for petroleum‐based epoxy resin curing agents, such as maleopimaric acid (MPA), are indispensable for sustainable fiber reinforced polymer composites with thermosetting matrices. However, previous investigations disregarded the importance of choosing the right stoichiometric ratio R between the anhydride groups in the rosin‐based curing agent and the epoxy groups in the resin. Therefore, the influence of R on the curing kinetics and mechanical properties of an epoxy resin cured with a rosin‐based anhydride is studied. Here, Fourier‐transform infrared spectroscopy (FT–IR) indicates that for R ⩾ 0.9 unreacted anhydride groups are present in the thermoset. Consequently, the network density decreases and the glass transition temperature Tg drops by about 40 °C. On the other hand, the steric hindrance of unreacted functional groups for R ⩾ 0.9, increases the flexural modulus and the reduced network density improves fracture toughness. The results indicate that the best R for overall high mechanical performance and good processability is preferably low (R ⩽ 0.7). Here, a low R results in a high Tg and good processability due to a low viscosity. However, the latency of the mixtures is low and therefore, the mixtures are not fit for processing via prepreg technology.https://doi.org/10.1002/mame.202300122bio‐based resinsepoxy resinsmaleopimaric acidmechanical propertiesrosinstoichiometric ratios |
| spellingShingle | Florian Rothenhäusler Marcel Kettenbach Holger Ruckdaeschel Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride Macromolecular Materials and Engineering bio‐based resins epoxy resins maleopimaric acid mechanical properties rosin stoichiometric ratios |
| title | Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride |
| title_full | Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride |
| title_fullStr | Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride |
| title_full_unstemmed | Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride |
| title_short | Influence of the Stoichiometric Ratio on the Curing Kinetics and Mechanical Properties of Epoxy Resin Cured with a Rosin‐Based Anhydride |
| title_sort | influence of the stoichiometric ratio on the curing kinetics and mechanical properties of epoxy resin cured with a rosin based anhydride |
| topic | bio‐based resins epoxy resins maleopimaric acid mechanical properties rosin stoichiometric ratios |
| url | https://doi.org/10.1002/mame.202300122 |
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