Fabrication of healable and flame-retardant polymer films based on phosphonate dynamic covalent crosslinking networks.
- 1Graduate School of Science and Engineering, Kansai University 3-3-35, Yamate-cho Suita Osaka 564-8680 Japan.
- 2Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University 3-3-35 Yamate-cho Suita-shi Osaka 564-8680 Japan [email protected].
- 3ORDIST, Kansai University 3-3-35 Yamate-cho Suita-shi Osaka 564-8680 Japan.
Abstract
Phosphoester linkages are attractive not only for flame retardancy but also dynamic covalent networks (DCNs) while preparing self-healing materials. However, thermal activation of these linkages may induce irreversible structural changes by condensation or volatile product evolution. In this study, phosphonate crosslinkages were investigated as an alternative dynamic linkage and directly compared with phosphoester crosslinkages in polymer networks based on poly(2-hydroxyethyl methacrylate) (PHEMA). Phosphoester- and phosphonate-crosslinked films were prepared using 2-methoxy-2-oxo-1,3,2-dioxaphosphorane or 2-methyl-2-oxo-1,3,2-dioxaphosphorane, respectively. Upon thermal treatment, the phosphoester-based DCN exhibited irreversible changes in mechanical properties and mass loss, resulting from the evolution of volatile byproducts during transesterification. Conversely, the phosphonate-based DCN maintained its mechanical properties and catalyst-free dynamic bond exchangeability with an activation energy of 122.0 kJ mol⁻¹, enabling repeatable thermal healing with approximately 99% recovery of the original tensile toughness. The two networks also exhibited distinct flame-retardant behaviors. Although both networks showed self-extinguishing behavior after flame exposure, the phosphonate-based DCN extinguished much more rapidly and exhibited substantially reduced internal thermal damage. Furthermore, the polymer film containing phosphonate-based DCNs exhibited superior flame-retardant properties owing to the instantaneous flame extinction capabilities by the P-C bonds. These results demonstrate that phosphonate-based dynamic crosslinking provides a promising strategy for designing multifunctional polymer networks that combine structural stability, thermal healing intrinsic flame retardancy.
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BibTeX
@article{maeda2026fabrication,
title = {{Fabrication of healable and flame-retardant polymer films based on phosphonate dynamic covalent crosslinking networks.}},
author = {Kazuho Maeda and Yota Okuno and Yasuhiko Iwasaki},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra08494j},
url = {https://europepmc.org/article/MED/42910230},
note = {CC BY},
}
RIS
TY - JOUR
TI - Fabrication of healable and flame-retardant polymer films based on phosphonate dynamic covalent crosslinking networks.
AU - Kazuho Maeda
AU - Yota Okuno
AU - Yasuhiko Iwasaki
PY - 2026
DA - 2026/10/21
JO - RSC advances
DO - 10.1039/d6ra08494j
UR - https://europepmc.org/article/MED/42910230
AB - Phosphoester linkages are attractive not only for flame retardancy but also dynamic covalent networks (DCNs) while preparing self-healing materials. However, thermal activation of these linkages may induce irreversible structural changes by condensation or volatile product evolution. In this study, phosphonate crosslinkages were investigated as an alternative dynamic linkage and directly compared with phosphoester crosslinkages in polymer networks based on poly(2-hydroxyethyl methacrylate) (PHEMA). Phosphoester- and phosphonate-crosslinked films were prepared using 2-methoxy-2-oxo-1,3,2-dioxaphosphorane or 2-methyl-2-oxo-1,3,2-dioxaphosphorane, respectively. Upon thermal treatment, the phosphoester-based DCN exhibited irreversible changes in mechanical properties and mass loss, resulting from the evolution of volatile byproducts during transesterification. Conversely, the phosphonate-based DCN maintained its mechanical properties and catalyst-free dynamic bond exchangeability with an activation energy of 122.0 kJ mol⁻¹, enabling repeatable thermal healing with approximately 99% recovery of the original tensile toughness. The two networks also exhibited distinct flame-retardant behaviors. Although both networks showed self-extinguishing behavior after flame exposure, the phosphonate-based DCN extinguished much more rapidly and exhibited substantially reduced internal thermal damage. Furthermore, the polymer film containing phosphonate-based DCNs exhibited superior flame-retardant properties owing to the instantaneous flame extinction capabilities by the P-C bonds. These results demonstrate that phosphonate-based dynamic crosslinking provides a promising strategy for designing multifunctional polymer networks that combine structural stability, thermal healing intrinsic flame retardancy.
SN - 2046-2069
ER -