偏硼酸根离子改性ZnMgAl层状双氢氧化物的制备及在聚氨酯弹性体中的应用

利用超声法制备偏硼酸根离子改性ZnMgAl层状双氢氧化物(B-LDHs),将其添加到聚氨酯弹性体(PUE)中制得PUE复合材料;通过锥形量热及烟密度研究了B-LDHs对PUE复合材料阻燃抑烟性能的影响,并通过复合材料的热失重、残炭的拉曼光谱及X射线光电子能谱分析其原因。结果表明,当B-LDHs的质量分数达到3%时,PUE复合材料的最大热释放速率及最大烟密度值相比于纯PUE的分别降低了59%和39%,表现出良好的阻燃抑烟性;这主要是由于BLDHs片层结构的物理阻隔作用,及其受热分解成的金属氧化物使炭层更加致密;另外,硼酸盐受热分解时能形成玻璃态膨胀层,隔绝氧气与热的传播,抑制可燃气体的扩散,提高复合材料受热分解时的残炭率及石墨化碳的形成,使得残炭的抗热氧化能力提高。

Metaboric ion Modified ZnMgAl-Layered Double Hydroxides as Flame Retardant for Polyurethane Elastomer

Metaboric ion modified ZnMgAl-layered double hydroxides (B-LDHs) were prepared by the ultrasonic method.The flame retardant was added to polyurethane elastomer (PUE) to investigate its flame retardancy and smoke suppression by cone calorimeter combustion test and smoke density test.The flame-retardant mechanism of BLDHs was studied by thermal gravimetric analysis,laser Raman spectroscopy and X-ray photoelectron spectroscopy.The results show that,compared to pure PUE,the peak heat release rate and maximum smoke density of PUE composites with 3％ B-LDHs are decreased by 59％ and 39％,respectively.The reasons are that the barrier effects of B-LDHs and metal oxides generated from the decomposition of the composites could raise the density of the char layer.Furthermore,the glassy state expansion layer formed by the decomposition of borate could cut off the spread of oxygen and heat,restrain the diffusion of combustible gas,improve the char yield of the PUE composites,promote the formation of graphite carbon,and improve the thermal oxidation resistance of the char residue.