一种可熔融的烷基次膦酸复盐阻燃剂的合成及其在PBT中的应用研究

通过甲基亚膦酸单丁酯与环己烯的自由基加成,然后与氢氧化钠以及硫酸镁和硫酸锌成盐制备得到一种可熔融的烷基次膦酸复盐阻燃剂-甲基环己基次膦酸锌镁MgZn(MHP)]。采用红外光谱(FTIR)、核磁氢谱(~1H NMR)以及X射线荧光光谱(XRF)等技术表征了目标产物,并通过熔融共混法制备MgZn(MHP)-PBT阻燃复合材料。添加质量分数为20%的MgZn(MHP)可使PBT的极限氧指数(LOI)由17. 7%提高至28. 2%,垂直燃烧测试达到UL94 V-0级别。微形量热测试表明MgZn(MHP)对PBT的热释放速率(HRR)抑制作用明显。热分解动力学结果表明,20%MgZn(MHP)-PBT复合材料在初始阶段的活化能比纯PBT的要低,而平均活化能则高于纯PBT。

Synthesis of a Meltable Alkylphosphinate Double Salt Flame Retardant and Its Application in PBT

A meltable alkylphosphonate double salt flame retardant-magnesium zinc methylcyclohexyl-phosphinate MgZn( MHP) ]was synthesized initially by radical addition reaction of n-butyl methylphosphonate with cyclohexene,followed by reacting with NaOH、MgSO4 and ZnSO4. The target product was characterized by fourier transforms infrared spectroscopy( FTIR) 、 hydrogen nuclear magnetic resonance(1 H NMR) and X-ray fluorescence spectrum( XRF). And the MgZn( MHP)-PBT composites were prepared by melt blending method. The limit oxygen index( LOI) of PBT containing 20% MgZn( MHP) increases from 17. 7% to 28. 2%,and the vertical burning test could pass UL94 V-0 rating. Microscale combustion calorimeter results indicate that MgZn( MHP) exhibites superior performance in the inhibition of heat release rate( HRR) for PBT. The results of thermal decomposition kinetics demonstrate that the20%MgZn( MHP)-PBT composite has lower activation energy( Ea) in initial decomposition stage but a higher average Eafor the whole stage comparing with pure PBT.