Abstract
Flame-retardant impregnation and densification are two major modification techniques to improve the fire safety of wood. Here, these two techniques were combined to prepare flame-retarded wood, aiming at further fire hazard reduction. The delignated Pinus sylvestris L. was impregnated with boric acid (BA) and graphene oxide (GO) solutions, then densified to prepare densified flame-retarded wood named BGO-DW sample. The results revealed that the BGO-DW sample obtained a limiting oxygen index (LOI) value of 47.4 %. Its backside temperature after 1200 s heating was 49 % lower than that of unmodified wood. Besides, the peak heat release rate (PHRR) and total heat release (THR) values of BGO-DW sample were 72 and 62 % lower than those of unmodified wood due to its shorter pyrolysis interval and lower peak mass loss rate (PMLR), as supported by thermogravimetric (TG) analysis. The flame retardancy of BGO-DW sample could be attributed to the formation of compatible char containing C=C aromatic structure, C–O–C cross-linked structure, and boron trioxide (B2O3) structure. These features of BGO-DW sample offer a new method to improve thermal stability, heat insulation, and flame retardancy for wood and wood-based products.
Funding source: National Natural Science Foundation of China
Award Identifier / Grant number: 52276143
Funding source: Key Research and Development Program of Hunan Province of China
Award Identifier / Grant number: 2021SK2054
Funding source: Fundamental Research Funds for Central Universities of the Central South University
Award Identifier / Grant number: 2023ZZTS0367
Acknowledgments
The authors thank the anonymous reviewers and the editor for their valuable and constructive comments on the manuscript.
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Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Competing interests: The authors have no conflicts of interest to declare that are relevant to the content of this article.
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Research funding: Financial support from the National Natural Science Foundation of China (no. 52276143), the Key Research and Development Program of Hunan Province (no. 2021SK2054), and the Fundamental Research Funds for the Central Universities of Central South University (no. 2023ZZTS0367) is acknowledged.
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