Abstract
Densified Pinus sylvestris wood was prepared via densification treatment at different compression pressures, and the flame retardancy and heat-insulating property of the resulting densified Pinus sylvestris wood are investigated by various analytical methods. The results verify that the densification treatment has a negligible effect on the composition and chemical structures of the wood, while the flame retardancy, smoke suppression and heat-insulating properties of wood are significantly increased. However, an excessive compression pressure will destroy the porous structure of wood, which results in the decrease in flame-retardant efficiency of the densified wood. When the compression pressure reaches 10 MPa, the resulting specimen presents the lowest fire hazard, which has 9.8% reduction in total heat release (THR), 37.1% reduction in total smoke release (TSR) and 25.9% reduction in equilibrium backside temperature at 2400 s compared to natural wood. Char formation analysis shows that the enhanced flame retardancy of densified wood can be attributed to a lower contact area between the wood and high-temperature environment accompanied with the generation of a strong and thermally stable char layer rich in aromatic and cross-linking structures. These attractive features of densified wood effectively reduce the transfer of heat and combustion rates when exposed to flame, resulting in better fire-retardant and heat-insulating properties during combustion.
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Funding
This study was funded by the National Natural Science Foundation of China (No. 51906261), the Key Research and Development Program of Hunan Province (No. 2021SK2054) and the High-Tech Industry Science and Technology Innovation Leading Plan of Hunan Province (No.2020GK2079).
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All authors contributed to the study conception and design. ZX: Methodology, conception, writing—review and editing; WZ: investigation, formal analysis, validation, data curation, writing—original draft preparation; YF: methodology, validation; XT: data curation; LY: writing—review and editing, supervision, project administration. All authors have read and agreed to the published version of the manuscript.
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Xu, Z., Zhao, W., Feng, Y. et al. Flame-retardant, heat-insulating and char formation properties of densified Pinus sylvestris treated with different compression pressures. Eur. J. Wood Prod. 80, 1321–1331 (2022). https://doi.org/10.1007/s00107-022-01859-7
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DOI: https://doi.org/10.1007/s00107-022-01859-7