二乙基次膦酸铝协同含磷有机硅阻燃PA66热分解动力学

Thermal Degradation Kinetics of Aluminum Diethylphosphinate in Synchronizing Phosphorous Silicone Flame-retarded PA66

以聚酰胺66(PA66)为基体,二乙基次膦酸铝(AlPi)和多聚苯磷酰硅油(PPSO)为阻燃剂,在密炼机上通过熔融共混制备了阻燃PA66,采用热重分析仪表征了阻燃PA66的热稳定性,通过Kissinger法(K法)和Flynn-Wall-Ozawa法(FWO)法分析了阻燃剂对材料热分解活化能的影响,并通过Coats-Redfern法进一步分析了材料的热分解机理和反应级数。实验结果表明,单独加入AlPi时,降低了材料的热分解活化能,使材料的分解提前,随着PPSO的加入,后期热分解活化能增加,提高了材料的热稳定性。纯PA66的机理函数G(α)=1–(1–α)1/4(0.10≤α≤0.90),反应级数为1/4,其为相边界反应分解机理;10%AlPi阻燃PA66的机理函数G(α)=α2(α≤0.35,α≥0.70)和G(α)=α3/2(0.40≤α≤0.65),反应级数分别为2和3/2,整个分解过程均为相边界反应分解机理;6%AlPi+2%PPSO阻燃PA66的机理函数G(α)=α+(1–α)ln(1–α)(α≤0.50)和G(α)=[–ln(1–α)]3(α≥0.50),反应级数分别为1和3,其分解机理分别为二维扩散的分解机理、随机成核和随后生长分解机理。

Flame-retard polyamide 66(PA66)were prepared by melt blending on an internal mixer using PA66 as matrix,aluminum diethylphosphinate(AlPi)and polyphenylphosphoryl silicone oil(PPSO)as flame retardants.The thermal stabilities of the flame-retard PA66 were characterized by thermogravimetric analysis,the effects of flame retardants on the thermal decomposition activation energy of the flame-retard PA66 were analyzed by Kissinger method and Flynn-Wall-Ozawa method,and the thermal decomposition mechanism and reaction order of the flame-retard PA66 were analyzed by Coats-Redfern method.The incorporation of AlPi alone reduces the thermal decomposition activation energy,it advances the decomposition of materials,while the addition of PPSO increases the activation energy of the thermal decomposition in the later period,which improves the thermal stabilities of the flame-retard PA66.Additionally,the kinetic mechanism functions of thermolysis of composites are listed as following:G(α)=1–(1–α)1/4(0.10≤α≤0.90),the reaction mechanism is phase-boundary reaction for pure PA66.G(α)=α2(α≤0.35,α≥0.70)and G(α)=α3/2(0.40≤α≤0.65),the reaction mechanism of the whole process is phase-boundary reaction for 10%AlPi flame-retard PA66.G(α)=α+(1–α)ln(1–α)(α≤0.50),the reaction mechanism is two-dimensional diffusion and G(α)=[–ln(1–α)]3(α≥0.5),the reaction mechanism is random nucleation and subsequent growth for 6%AlPi and 2%PPSO lame-retard PA66.