Liquid phosphorus-based bis-imidazole compounds as latent curing agents for enhancing thermal, mechanical, and flame-retardant performances of single-component epoxy resins
Article
Article Title | Liquid phosphorus-based bis-imidazole compounds as latent curing agents for enhancing thermal, mechanical, and flame-retardant performances of single-component epoxy resins |
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ERA Journal ID | 1691 |
Article Category | Article |
Authors | Wang, Jingsheng, Wang, Jun, Wang, Fengyi, Yang, Shuang, Wu, Chaoqun, Chen, Xi, Chen, Kaiwen, Song, Pingan, Wang, Hao and Huo, Siqi |
Journal Title | Polymer Degradation and Stability |
Journal Citation | 230 |
Article Number | 111066 |
Number of Pages | 13 |
Year | 2024 |
Publisher | Elsevier |
Place of Publication | United Kingdom |
ISSN | 0141-3910 |
0144-2880 | |
1873-2321 | |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.polymdegradstab.2024.111066 |
Web Address (URL) | https://www.sciencedirect.com/science/article/abs/pii/S0141391024004099 |
Abstract | The escalating need for advanced, fire-resistant, single-component epoxy resin (EP) is fueled by its practicality and economic benefits, highlighting the necessity for the development of multifunctional flame-retardant latent curing agents. Herein, two liquid phosphorus-containing bis-imidazole compounds, PPDM and DPCMI, were synthesized as latent curing agents for EP, demonstrating multiple effects in improving latency, thermal stability, mechanical properties, and fire safety. EP/PPDM and EP/DPCMI showcased superior storage stability and rapid curing at moderate temperatures, with EP/PPDM standing out for its long shelf life of 7 d and being gelled within 18 min at 100 °C. The resulting thermosets presented increased glass transition temperatures (189.5 and 178.9 °C), due to the enhanced crosslinking densities. The presence of bis-imidazole groups in PPDM and DPCMI enabled EPs to form denser crosslinked networks, leading to improved mechanical strength and toughness. The limiting oxygen index (LOI) values of EP/PPDM and EP/DPCMI reached 29.5% and 29.0%, respectively. Compared to the control EP, EP/PPDM and EP/DPCMI showed 23.1% and 18.8% reductions in total heat release and 22.0% and 23.11% decreases in total smoke production. These results confirm the enhanced flame retardancy and smoke suppression of EP/PPDM and EP/DPCMI because of introducing phosphorus-containing groups. Even though the curing time was halved to 2.5 hours, EP/PPDM systems maintained satisfactory overall performances. Therefore, this work offers a scalable strategy for the fabrication of single-component EP systems combining rapid curing, satisfactory flame retardancy, and enhanced thermal stability and mechanical properties, aligning with the needs of industrial applications. |
Keywords | Single-component epoxy resin; Phosphorus-containing bis-imidazole compounds; Flame retardancy; Mechanical property |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 401609. Polymers and plastics |
Public Notes | The accessible file is the accepted version of the paper. Please refer to the URL for the published version. |
Byline Affiliations | Wuhan University of Technology, China |
School of Agriculture and Environmental Science | |
School of Engineering |
https://research.usq.edu.au/item/zq200/liquid-phosphorus-based-bis-imidazole-compounds-as-latent-curing-agents-for-enhancing-thermal-mechanical-and-flame-retardant-performances-of-single-component-epoxy-resins
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