一种碳点阻燃聚对苯二甲酸乙二醇酯的性能

Flame Retardant Properties of Polyethylene Terephthalate Composites with Carbon Dots

为实现聚对苯二甲酸乙二醇酯(PET)的高效阻燃,采用一种同时含有N和Si的新型碳点(CDs)对PET进行阻燃改性。通过透射电镜、X射线光电子能谱仪和红外光谱对CDs进行分子结构表征,并采用极限氧指数测试仪(LOI)、垂直燃烧仪和锥形量热仪对CDs/PET复合材料的阻燃性能进行了测试和分析。研究结果表明,当CDs质量分数为4%时,PET的LOI值由21.2%上升到29.4%,且燃烧过程中产生的热释放速率峰值由513.2 k W/m~2下降到433.7 kW/m~2、总产热量由71.9 MJ/m~2下降到54.0 MJ/m~2,且烟释放速率与总生烟量下降、残炭量增加,说明CDs的添加能降低PET燃烧过程中产生的热危害与烟危害;此外,通过量化阻燃模式得出,CDs对PET的阻燃效应是物理阻隔、抑制火焰及催化成炭3种效应的叠加,3种效应比例分别为36.5%,24.3%和10.8%。

In order to achieve the highly-efficient flame retardancy of polyethylene terephthalate(PET),carbon dots(CDs) with N and Si element were used to modify PET and prepare CDs/PET composites.The molecular structure of CDs was characterized by transmission electron microscopy,X-ray photoelectron spectroscopy(XPS) and infrared spectroscopy(FT-IR).The flame retardants of CDs/PET composites were evaluated and analyzed by the limiting oxygen index tester(LOI),vertical combustion meter(UL-94) and cone calorimeter(CONE).The results show that,when the mass fraction of CDs is 4%,the LOI value of PET is increased from the 21.2% to 29.4%.And during the combustion process,the peak heat release rate of PET drops from 513.2 kW/m~2to 433.7 kW/m~2.The total heat release decreases from 71.9 MJ/m~2to 54.0 MJ/m~2.Both the smoke release rate and total smoke generation all decrease,and the residue amount of PET increases.These demonstrate that,the addition of CDs can reduce the thermal hazard and smoke hazard during PET combustion.In addition,by quantifying the flame retardant mode,it is concluded that the flame retardant effect of CDs on PET is the superposition of three effects:physical barrier,flame inhibition and catalytic charring,and the proportions of the above effects are 36.5%,24.3% and 10.8%,respectively.