三嗪膨胀阻燃剂/硅酸镁协效阻燃TPU的制备及性能研究

Investigation on Preparation and Properties of Synergistic Flame Retardant TPU with Triazine Intumescent Flame Retardant/Magnesium Silicate

以三嗪成炭发泡剂(CFA)及聚磷酸铵(APP)复配成膨胀阻燃剂(IFR),以硅酸镁(MgSiO3)为协效剂添加到热塑性聚氨酯弹性体(TPU)中制备阻燃TPU材料,研究了阻燃TPU材料的阻燃性能、力学性能、热降解行为和炭层的表面形貌。结果表明,纯TPU材料的极限氧指数仅为22.0%,在空气中极易燃烧,当IFR添加量为28%(质量分数,下同),MgSiO3添加量5%时,材料的极限氧指数提高到37.1%,通过UL 94V-0级,表现出很好的阻燃效果;但是IFR/MgSiO3的加入使材料的拉伸强度和断裂伸长率明显下降,也使得TPU材料的起始热分解温度提前,最大热降解速率峰值降低,同时材料的残炭量得到了很大程度的提高。

The flame-retardant polyurethane(TPU)compounds were prepared by using triazine charring-foaming agent(CFA)and ammonium polyphosphate(APP)as intumescent flame retardants(IFR)and magnesium silicate(MgSiO3)as a synergistic flame retardant.The flame retardant performance,mechanical properties,thermal decomposition behaviors and morphologies of the char layers were investigated.The results indicated that the limiting oxygen index of pure TPU was only 22.0 vol%,leading to flammability in the air.The flame-retardant TPU compounds achieved an limiting oxygen index of 37.1 vol%with the addition of 28 wt%IFR and 5 wt%MgSiO3,and they also reached a V-0 rating according to the UL 94 classification.However,their tensile strength and elongation at break decreased significantly due to the incorporation of these flame retardants.TGA results indicated that the thermal decomposition temperature and maximum thermal degradation rate of flame-retardant TPU compounds were reduced with the addition of flame retardants,but the residual char content was improved significantly.