MWNTs/CMSs/PET阻燃材料的结构及阻燃机理

Structure and Flame Retardant Property of Composite Materials MWNTs/CMSs/PET

采用熔融共混法与阻燃剂复配法制备了MWNTs/CMSs/PET复合材料。通过扫描电镜(SEM)、极限氧指数法(LOI)、UL94垂直燃烧法、锥形量热仪(Cone)及热重红外联用分析仪(TG-IR)表征了样品的结构、阻燃性能及热降解行为,分析了MWNTs/CMSs阻燃PET材料的阻燃机理。结果表明,当MWNTs/CMSs添加量为1%(质量分数),MWNTs与CMSs质量比为1:1/2时,二者可有机地结合为一个整体,有利于MWNTs/CMSs在PET基材中发挥协同阻燃作用。与纯PET及CMSs/PET相比,MWNTs/CMSs/PET能有效降低火灾危险性。MWNTs/CMSs阻燃PET主要是通过MWNT与CMSs两者的协同作用延缓PET热裂解行为,一方面MWNTs在其燃烧时可在PET表面形成致密的网络状炭层结构,减少了熔滴的产生;另一方面CMSs其燃烧时在PET表面形成湍流炭,以此阻止氧气和热量进入PET内部,同时释放出不燃气体CO2以降低周围环境中可燃气体的浓度,阻止燃烧的继续进行,最终实现了MWNTs/CMSs/PET材料的良好阻燃。

Composites of Multi-walled carbon nanotubes（MWNTs）, carbon microspheres（CMSs）and Polyethylene terephthalate（PET） were prepared by melt blending method.The structures, flame retardancy and pyrolysis behavior of the composites were characterized by scanning electron microscope（SEM）and infrared spectroscopy（IR）, as well as limiting oxygen index（LOI）method, vertical burning method（UL-94）, cone calorimeter and thermal gravimetric analysis（TG）.The results showed that the addition of 1%（mass fraction） of（1MWNTs ＋ 0.5CMSs） into PET resulted in a good comprehensive flame retardancyof the composite. Moreover, in comparison with the pure PET and CMSs/PET, the composites MWNTs/CMSs/PET could reduce effectively the fire risk. The pyrolysis process of PET could be suppressed by the synergistic effect of MWNTs and CMSs due to the following that during burning, on one hand, MWNTs might give rise to form a three-dimensional network of compact carbon layeron the PETsurface to decrease the melt drips; on the other hand, CMSs might produce a turbulent carbon layer on the surface of PET, preventing the oxygen and heat from entering the interior of PET and thus releasing the non-flammable CO2 to reduce the concentration of combustible gas in the surrounding environment.