二乙基次磷酸铝在增强聚酰胺体系中的阻燃机理

Flame Retardant Mechanism of Aluminium Dipropylphosphinate in Reinforced Polyamide System

通过锥形量热、垂直燃烧、热重分析、傅立叶变换红外光谱以及扫描电子显微镜探究了二乙基次磷酸铝(AlPi)在增强聚酰胺体系中的阻燃机理。结果表明,PA66/AlPi、PA6T/AlPi,PA10T/AlPi三种体系的凝聚相成炭能力顺序为PA6T/AlPi>PA10T/AlPi>PA66/AlPi,气相捕捉自由基能力顺序为PA66/AlPi>PA6T/AlPi>PA10T/AlPi。阻燃性能主要受树脂与AlPi的降解温度是否匹配,树脂结构的酰胺基团含量以及苯环含量的影响,且影响因素间相互制约。同时明确其阻燃机理:表面主要发生热氧降解,形成磷酸盐和芳香族物质的炭层,进而起到凝固相阻燃的作用;内部以热降解为主形成磷酸盐的同时有AlPi气体挥发,起到气相阻燃的作用。

The flame retardant mechanism of aluminum dipropylphosphinate(AlPi)in reinforced polyamide system was studied by cone calorimetry,vertical combustion,TGA,FTIR and SEM.The results show that the coalescence ability of PA66/AlPi,PA6T/AlPi,PA10T/AlPi is PA6T/AlPi>PA10T/AlPi>PA66/AlPi,and the ability of capturing free radicals in gas phase is PA66/AlPi>PA6T/AlPi>PA10T/AlPi.The main influencing factures of flame retardant performance are whether the degradation temperature of resin and AlPi is matched,the content of amide group of resin structure and its own benzene ring,and the influencing factures are mutually restricted.At the same time,the flame-retardant mechanism is clarified:thermal oxygen degradation mainly occurs on the surface,forming the carbon layer of phosphate and aromatic substances,and then playing the role of flame-retardant in the solidification phase;thermal degradation takes place in the interior,forming the phosphate,and volatilization of AlPi gas,which plays the role of gas-phase flame-retardant.