ATH/OMMT复合改性沥青阻燃抑烟性能与机理分析

Analysis of Flame-Retarding and Smoke Suppressing Performance and Mechanism of ATH/OMMT Modified Asphalt

对ATH、OMMT改性沥青的阻燃抑烟性能进行了研究,将ATH、OMMT两种改性剂按照不同配比进行复配,研究了不同配比的复合阻燃剂对沥青常规性能、阻燃抑烟性能的影响,评价了不同配比复合阻燃剂的协同效果,并采用X射线衍射(XRD)、红外光谱(FTIR)等手段研究了沥青改性前后的微观结构变化,采用扫描电镜(SEM)、X射线能谱仪(EDS)等手段研究了沥青燃烧后的碳层结构及元素组成,探究了ATH/OMMT复合阻燃体系的阻燃机理。结果表明,单掺OMMT对沥青阻燃抑烟性能的提升非常有限,而单掺ATH虽然能有效提高沥青的阻燃性能但需要的掺量较大。OMMT与ATH间存在良好的协同效果,能够有效提高沥青的阻燃性能和抑烟性能。不同掺量(1%、3%、5%)的OMMT在SBS改性沥青中均形成了剥离型纳米复合材料,在OMMT改性沥青的红外光谱中,1092 cm-1、1032 cm-1、517 cm-1、463 cm-1四处特征峰的峰面积指数与沥青中OMMT掺量之间展现出良好的线性关系。在ATH/OMMT复合阻燃抑烟沥青的热解燃烧过程中,ATH受热产生的Al2O3依附于聚集在沥青表面的OMMT片层上,形成了一种耐火的致密复合阻隔层,可以高效地阻隔沥青燃烧过程中的热量及物质传递,减少了可燃轻质组分的析出量,增加了成碳比例,使得ATH/OMMT复合改性沥青具备良好的阻燃抑烟性能。

On the basis of researching the flame retardant and smoke suppression performance of ATH and OMMT modified asphalt,ATH and OMMT were compounded according to different proportions.The effects of different proportions of composite flame retardants on asphalt road performance,flame retardant and smoke suppression properties were studied and the synergistic effect of different proportions of composite flame retardants was evaluated.The structural changes of asphalt before and after modification were studied by means of XRD and FTIR.The structure and element composition of carbon layer after asphalt combustion were studied by means of SEM and EDS,and the flame retardant mechanism of ATH/OMMT composite flame retardant system was explored.The results show that the improvement of flame retardant and smoke suppression performance of asphalt with single addition of OMMT is very limited,while single addition of ATH can effectively improve the flame retardancy of asphalt,but a large amount of ATH is needed.There is a good synergistic effect between OMMT and ATH,which can effectively improve the flame retardancy and smoke suppression performance of asphalt.Exfoliated nanocomposites are formed in SBS modified asphalt with different OMMT content(1%,3%,5%).In the infrared spectrum of OMMT modified asphalt,there is a good linear relationship between the peak area index of four characteristic peaks of 1092 cm-1,1032 cm-1,517 cm-1,463 cm-1 and the content of OMMT in asphalt.In the pyrolysis combustion process of ATH/OMMT composite flame retardant and smoke suppression asphalt,the Al2O3 produced by ATH heating is attached to the OMMT layer gathered on the asphalt surface,forming a fire-resistant and dense composite barrier layer,which can effectively block the heat and material transfer in the process of asphalt combustion,reduce the precipitation of combustible light components,increase the carbon ratio,and make ATH/OMMT composite modified asphalt have good flame retardant and smoke suppression performance.