锥形量热法研究木质素基膨胀型阻燃剂对环氧树脂阻燃抑烟效果

Study on Effect of Lignin⁃based Intumescent Flame Retardant on Flame Retardancy and Smoke Suppression of Epoxy Resin using Cone Calorimetry

以来自自然界储量第二的木质素作为膨胀型阻燃剂的基体,通过接枝氮、磷元素成功合成碳源、酸源、气源三位一体的木质素基膨胀型阻燃剂(Lig-T),实现了良好的阻燃性能。将Lig-T按照不同含量添加到环氧树脂(EP)中制备EP/Lig-T复合材料,以锥形量热测试考察复合材料的热稳定性能和阻燃性能,并重点考察复合材料在接近真实火灾事故时的热释放和烟释放规律。结果表明,当Lig-T含量为20%(质量分数,下同)时,复合材料的热释放速率峰值为1 374 kW/m^(2)、热释放总量为41.63 MJ/m~2、烟释放总量为1 634 m^(2)/m^(2),与EP参比试样的数值相比,均呈现下降的趋势,燃烧结束的残炭率从4.26%增至10.01%。基于气相和凝聚相的协效阻燃机理,木质素作为膨胀型阻燃剂的碳源使得复合材料在高温条件下具备更好的成炭效果,在燃烧过程中形成稳定且致密的炭层结构,在实现高效阻燃的同时减少有毒烟气的释放,降低火灾的危害。

With the second largest reserve in nature,lignin was used as a supporting matrix for intumescent flame retar⁃dant.A lignin⁃based intumescent flame retardant named as Lig⁃T was successfully synthesized through introducing ni⁃trogenous and phosphorus elements.In this flame retardant,the carbon source,acid source and gas source were integrat⁃ed to achieve good flame retardancy.Epoxy resin(EP)/Lig⁃T composites were prepared at different mass fractions,and their thermal stability and flame retardancy were investigated through cone calorimetry,focusing on the heat release and smoke release law to simulate the condition of real fire accident.The results indicated that when the mass fraction of Lig⁃T was 20%,the composites obtained a peak heat release rate of 1960 kW/m2,a total heat release of 60.80 MJ/m^(2),and a total smoke release of 1634 m^(2)/m^(2).All of these data exhibited a downward trend compared to the values of pure epoxy resin.In addition,the residual char yield at the end of combustion was increased from 4.26 to 10.01 wt%.Based on the synergistic flame retardant mechanism of gas phase and condensed phase,lignin can act as a carbon source of intumescent flame retardants to endow the composites with a better carbon⁃forming effect at high temperature,resulting in the forma⁃tion of a stable and dense carbon layer structure during the combustion process.This work demonstrated that lignin can reduce the release of toxic gas as well as achieve a high⁃efficient flame⁃retardant effect,thus reducing the risk of fire.