尼龙66的多重熔融行为

研究了尼龙66的双重熔融峰的转变行为。高温峰(峰1)的熔融温度几乎不变,低温峰(峰2)的熔融温度随着退火时间的延长逐渐升高。全部退火时间内双峰的总面积保持不变,而高温峰、低温峰的相对面积比变小。高温峰被认为来自于熔体的快速冷却(动力学优先),低温峰则来自于缓慢冷却(热力学优先)。低温峰向高温峰的转变是由于不同的结晶尺寸和/或完善程度引起。

Multiple Endothermo Melting Behavior in Nylon 66

Either of the two endothermic melting peaks of nylon 66 found by differential thermal analysis can be converted to the other by appropriate choice of annealing conditions. The two peaks are considered due to the melting of two morphological species, forms 1 and forms 2. Form 1 is relatively fixed in melting temperature, while the melting temperature of form 2 varies with annealing conditions. It has been shown that form 1 results from rapid cooling from the melt, and form 2 results from slow cooling. Form 1 appears to be kinetically favored, while form 2 is thermodynamically preferred. The variability in the form 2 melting point is attributed to variable crystal size and/or perfection.