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.

中文翻译：

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阻燃浸渍与致密化处理相结合将樟子松加工成隔热、热稳定、阻燃材料

阻燃浸渍和致密化是提高木材防火安全性的两种主要改性技术。在这里，这两种技术结合起来制备阻燃木材，旨在进一步减少火灾危险。指定的樟子松L.用硼酸（BA）和氧化石墨烯（GO）溶液浸渍，然后致密化制备致密化阻燃木材，命名为BGO-DW样品。结果显示，BGO-DW 样品的极限氧指数 (LOI) 值为 47.4%。加热1200秒后其背面温度比未改性木材低49%。此外，由于其较短的热解间隔和较低的峰值质量损失率（PMLR），BGO-DW样品的峰值热释放率（PHRR）和总热释放（THR）值比未改性木材低72％和62％，由热重 (TG) 分析支持。BGO-DW样品的阻燃性可归因于形成含有C=C芳香族结构、C-O-C交联结构和三氧化硼（B2氧3） 结构。BGO-DW 样品的这些特性为提高木材和木制品的热稳定性、隔热性和阻燃性提供了一种新方法。