芳香多酸镧配合物的制备及其改性PA66的抗黄变性与力学性能的研究

Study on Preparation of Lanthanum Binary Aromatic Acid Complexes and Their Application for Anti-yellowing and Improvement of Mechanical Properties of Polyamide 66

黄变不仅改变了聚酰胺(尼龙)的外观与微观结构,而且也缩短了其使用寿命,研究聚酰胺抗热氧老化及抗黄变性能有着重要意义。利用溶液法、低温固相法与超声波合成法合成了芳香多酸镧,探讨了芳香多酸镧对PA66的热氧化稳定性、力学性能与阻燃性能的影响。采用红外光谱、扫描电镜、X射线衍射与热重法等对芳香多酸镧的形貌和微观结构与性能进行了表征。结果表明,混合芳香多酸镧配合物(均苯四甲酸和偏苯三甲酸摩尔比1∶1,溶液法,简称PT11)是一种球状或者棒状、带有微孔的结晶性化合物,其最大热分解温度超过500℃,可充当聚酰胺补强与热氧化稳定剂。PT11推迟PA66热降解过程。PT11P(P表示超声波法)改性PA66黄变指数为31.9%,而纯PA66为45.6%,提高了PA66抗黄变效果,并改善了PA66纤维的拉伸性能。与纯PA66纤维相比,PT11改性PA66纤维的总燃烧热与最大热释放速率分别下降了22.6%和18.6%,其阻燃效果明显。

Nylon yellowing not only changes the appearance and microstructure of polyamide but also shortens its service life.It is of great significance to study the anti-oxidation and anti-yellowing properties of polyamide.In this paper,the lanthanum aromatic carboxylic acid mixture was synthesized with solution,low-temperature solid state,and ultrasonic methods.The effects of the lanthanum aromatic acid mixture on the thermo-oxidative stability,mechanical properties,and flame retardancy of PA66 fibers were investigated.The microstructure and properties of lanthanum aromatic carboxylate were characterized by infrared spectroscopy,scanning electron microscopy,X-ray diffraction,and thermogravimetry.The results show that the lanthanum aromatic acid mixture complex(PT11)is a spherical or rod-like,porous crystalline compound.Its maximum thermal decomposition temperature is more than 500℃,which can be used as a reinforcing and therm-oxidative stabilizer for polyamide.PT11 delays thermal degradation of PA66,improves the yellowing resistance of PA66(the yellowing index of PT11P of modified PA66 was 31.9%,whereas that of raw PA66 was 45.6%),and enhances the tensile properties of PA66 fiber.The total heat release and peak heat release rates of PT11-modified PA66 fiber were reduced by 22.6% and 18.6% respectively,as compared with raw PA66 fiber.