PA66结晶记忆效应影响因素研究

Study on Factors Influencing Memory Effect of the PA66 Crystallization

记忆效应是PA66结晶过程中普遍存在的一种现象,这种现象的存在导致PA66在不同的配方中或者不同的加工条件下表现出的结晶行为存在较大差异。其中,记忆效应对PA66结晶行为的影响主要表现为提升材料的结晶温度。该研究将毛细管流变仪作为加工设备,通过施加不同的加工条件制备得到不同状态的PA66树脂颗粒,通过DSC对所有样品的结晶及熔融行为进行表征,通过一系列对比分析,明确影响PA66记忆效应的主导因素。研究发现,剪切、温度以及滞留时间均能够影响PA66的记忆行为。剪切作用的存在能够显著提升PA66的结晶温度,因此,剪切作用能够强化PA66的记忆效应;而温度的提升和滞留时间的延长均会导致PA66结晶温度的下降,因此,这两种因素对记忆效应起到了抑制作用。总体而言,记忆效应的强弱与分子链链间的氢键相互作用密切相关,而剪切作用是影响材料记忆效应的主导因素。

Memory effect is a common phenomenon in the crystallization process of PA66.This phenomenon leads to a large difference in the crystallization behavior of PA66 in different formulations or under different processing conditions.Among them,the memory effect will increase the crystallization temperature of PA66.In this paper,the capillary rheometer was used to prepare PA66 resin particles with different states at different processing conditions.The crystallization and melting behavior of all samples were characterized by DSC.Through a series of comparative analysis,the main factors affecting PA66 memory effect were clarified.The study found that shearing,temperature and residence time can all affect PA66's memory behavior.Shearing can significantly increase the crystallization temperature of PA66,which strengthens the memory effect of PA66.The increase of temperature and the extension of residence time will lead to the decrease of the crystallization temperature of PA66.Therefore,the above two factors play an inhibitory role on the memory effect.In general,the memory effect is closely related to the hydrogen bond interaction between molecular chains,and shearing is the dominant factor affecting the memory effect of the material.