聚焦磷酸哌嗪对PA6燃烧及热稳定性能的影响

Fire and Thermal Stability Properties of Polyamide 6 with Piperazine Polypyrophosphate

以磷酸和哌嗪为原料,采用热合成工艺,合成了新型的无卤磷氮型阻燃剂聚焦磷酸哌嗪(piperazine polypyrophosphate,PAPP),并考察PAPP对尼龙6材料燃烧性能的影响。采用傅里叶红外光谱(FTIR)、核磁共振氢谱(~1H-NMR)及元素分析表征PAPP的结构。FTIR分析结果显示,PAPP结构中所有的特征峰均在谱图中有所显示。核磁共振氢谱(~1H-NMR)结果显示,PAPP结构中存在两种空间位置的H元素,与理论结构一致。元素分析显示,PAPP的理论元素含量和实际元素含量是相互一致的,表明PAPP的理论结构和实际结构一致。采用热重分析(TG)评价了PAPP的热降解行为。实验表明,PAPP的初始分解温度(T_(5%))为305°C,800°C的残炭量为10. 6%,具有较高的热稳定性和成炭性能。当PA6中PAPP添加量为40%质量分数时,复合材料的极限氧指数(LOI)上升到42. 0%,达到UL94V-0级。TG测试表明,随着PAPP添加量的增加,PA6/PAPP复合材料残炭量持续上升。微型量热分析(MCC)测试显示PAPP添加量的持续增加显著地降低了复合材料的热释放峰值(PHRR)和总热释放(THR)。

An intermediate piperazine diphosphate and a novel halogen-free nitrogen phosphorus flame retardant pyrophosphate piperazine (piperazine polypyrophosphate, PAPP) were synthesized through two-step dehydration reaction with phosphoric acid and piperazine as raw materials. The flame retarding properties and thermal stability of polyamide 6 with PAPP were studied. The chemical structure of PAPP was characterized with the Fourier transform infrared (FT-IR), the proton nuclear magnetic resonance spectroscopy ( 1H-NMR) and element analysis. From the FT-IR test, all the characteristic peaks of PAPP structure were shown in the spectral graph. From the 1H-NMR test, there were two H elements of spatial position in PAPP structure, which were consistent with the theoretical structure. Moreover, the theoretical element content and the actual element content were consistent, indicating that the theoretical structure and actual structure of PAPP were consistent. Meanwhile, the pyrolysis behavior of PA6 composites was studied by thermogravimetric analysis (TGA). The initial degradation temperature ( T 5%, the temperature at which the mass loss of 5%) of PAPP was about 305℃. The prepared PAPP had a final mass residue of 10.6%at 800℃, showing high thermal stability and char forming properties. PA6/PAPP40 exhibited a LOI value of 42.0% and achieved the V-0 rating after the introduction of 40% mass fraction PAPP. TGA results show that the introduction of PAPP greatly increased the stability of the PA6/PAPP at high temperature and resulted in a significant increase of char residue. The MCC test indicated that the proper amount of PAPP can greatly decrease the peak heat release rate (PHRR) and total heat release (THR).