Polyamide 6 (PA6) and stabilized PA6 with two different thermal stabilizers, (ie, metal salts CuI/KI and hindered amine KYN818 [1,3‐benzendicarboxamide,N,N'‐bis(2,2,6,6‐tetramethyl‐4‐piperidinyl)]) were separately prepared by melt blending and then aged for different time. The effects of aging temperature and aging time on crystallization behaviors of PA6 and stabilized PA6 were systematically investigated by differential scanning calorimetry and X‐ray diffraction. The variations of melting temperature, crystallinity and 2θ values suggest that aging under high temperature will accelerate the formation of crystals initially and then the degradation of molecular chains. The yellowness index and maximum decomposition temperature of stabilized PA6 are higher than that of PA6, which is dominated by different aging mechanisms and properties of stabilizers. In addition, the viscosity of all systems is increased at the preliminary stage, which is caused by the crosslinking network and the post‐polycondensation. The results of dynamic mechanical analysis showed that the glass transition temperature (T_g) decreases because the degradation of molecular chains during the aging process. Moreover, the carbonyl index for stabilized PA6 is lower than PA6, indicating the degradation is hindered by stabilizers. A comparison of the stabilization performance between CuI/KI and KYN818 was investigated to differentiate the long‐term stabilizing efficiency.

中文翻译：

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聚酰胺6热氧化稳定性的新见解：受阻胺和CuI / KI作用的比较研究

聚酰胺6（PA6）和具有两种不同热稳定剂的稳定化PA6（即金属盐CuI / KI和受阻胺KYN818 [1,3-苯二甲酰胺，N，N'-双（2,2,6,6-四甲基-通过熔融共混分别制备4-哌啶基）]），然后老化不同的时间。通过差示扫描量热法和X射线衍射系统地研究了时效温度和时效时间对PA6和稳定PA6结晶行为的影响。熔融温度，结晶度和2的变型θ值表明，高温下的老化将首先加速晶体的形成，然后加速分子链的降解。稳定的PA6的泛黄指数和最高分解温度均高于PA6，这主要归因于不同的老化机理和稳定剂的性能。此外，由于交联网络和后缩聚反应，所有体系的粘度在初始阶段都会增加。动态力学分析结果表明，玻璃化转变温度（T _g）减少是因为在老化过程中分子链的降解。此外，稳定化的PA6的羰基指数低于PA6，表明降解受到稳定剂的阻碍。比较了CuI / KI和KYN818的稳定性能，以区分长期稳定效率。