A flame-retardant composition (FRC) composed of a surface-treated calcium carbonate-based mineral, having high porosity and loaded with deliquescent calcium chloride, was assessed for its potential as a flame retardant. Two FRCs with 16% and 26% calcium chloride (dry solid) stored in the pore structure, respectively, were studied with respect to their ability to absorb and release free water, and their efficacy in melamine–urea–formaldehyde (MUF)-bonded wood composites was investigated. Water absorption capacity was determined by performing absorption tests at a temperature of 20 °C and relative humidity (RH) of 65% and 95%, and the water release behavior was studied by performing thermogravimetric analysis. The FRCs have the capacity to hold substantial amounts of water (up to 60 wt%), but still behave as a free-flowing powder. The influence of addition of 10 and 20 wt% FRC in wood composites on reaction to fire and strength properties was determined by measuring the self-extinguishing time after flame exposure and internal bond strength, respectively. These effects were evaluated by comparison with ground calcium carbonate (GCC) and commercially available nitrogen containing phosphorus-based fire retardant. Although the FRCs had a negative impact on internal bond strength, the results confirmed their flame-retardant potential and showed that 10–15% by weight of the flame retardant would be a good compromise, in terms of the trade-off between flame retardancy and mechanical properties. The synergistic effects of multiple flame retardancy reaction mechanisms due to the presence of inorganic minerals and a hygroscopic agent, CaCl2, are also discussed. The unique properties of the FRC, which allow to exploit the fire-retardant potential of CaCl2 while at the same time eliminating the risk associated with the emission of hydrogen chloride gas during combustion, are confirmed by the results of FTIR spectroscopic analyses of the flue gas.

中文翻译：

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含潮解盐的矿物基组合物作为三聚氰胺-尿素-甲醛 (MUF) 粘合木材复合材料的阻燃剂

评估了阻燃组合物 (FRC) 作为阻燃剂的潜力，该组合物由表面处理的碳酸钙基矿物组成，具有高孔隙率并负载有易潮解的氯化钙。分别在孔隙结构中储存了 16% 和 26% 氯化钙（干固体）的两种 FRC 研究了它们吸收和释放游离水的能力，以及它们在三聚氰胺 - 尿素 - 甲醛（MUF）键合中的功效木复合材料进行了研究。通过在20°C的温度和65%和95%的相对湿度（RH）下进行吸水测试来确定吸水能力，并通过进行热重分析来研究放水行为。FRC 能够容纳大量的水（高达 60 wt%），但仍表现为自由流动的粉末。分别通过测量火焰暴露后的自熄时间和内部粘合强度来确定在木质复合材料中添加 10 和 20 重量％的 FRC 对防火反应和强度性能的影响。通过与重质碳酸钙 (GCC) 和市售含氮磷基阻燃剂进行比较来评估这些效果。尽管 FRC 对内部粘合强度有负面影响，但结果证实了它们的阻燃潜力，并表明 10-15%（重量）的阻燃剂将是一个很好的折衷方案，在阻燃性和机械性能。还讨论了由于无机矿物和吸湿剂 CaCl2 的存在而导致的多种阻燃反应机制的协同效应。