The crystallization and melting behavior of polymers is of theoretical importance. In this work, poly(butylene succinate) (PBS) was selected as an example to study such behavior at low supercooling via introduction of the extended-chain crystal (ECC) of the same polymer as nucleating agent. The crystallization of PBS with its ECC as nucleating agent in a wide temperature range (90–127 °C) and the following melting behavior were studied. It is revealed that the melting point (T_m, for T_c≥113 °C) and the annealing peak temperature (T_a, for T_c=90–100 °C) show similar asymptotic behavior. Both T_m and T_a approach to a value of ca. 3.3 °C higher than the corresponding T_c when the crystallization time t_c approaches the starting point. That is to say, the Hoffman-Weeks plot is parallel to T_m=T_c line. The crystallization line became parallel to the melting line when PBS was crystallized at T_c higher than 102 °C. Based on these results, we propose that the parallel relationship and the intrinsic similarity between the T_a and the T_m observed at the two ends of the T_c range could be attributed to the metastable crystals formed at the beginning of crystallization.

聚合物的结晶和熔融行为具有理论重要性。在这项工作中，选择聚丁二酸丁二酯（PBS）作为示例，通过引入与成核剂相同的聚合物的延伸链晶体（ECC）研究低过冷时的这种行为。研究了以ECC为成核剂的PBS在较宽的温度范围（90–127°C）中的结晶和以下熔融行为。据透露，熔点（Ť_米，对于Ť _Ç ≥113℃）和退火峰温度（Ť_一个，用于Ť _Ç = 90-100℃）显示出类似的渐进行为。既Ť_米和Ť_一个方法的价值CA。当结晶时间t _c接近起点时，温度比相应的T _c高3.3°C 。也就是说，霍夫曼-韦克斯图与T _m = T _c线平行。当PBS在高于102°C的T _c结晶时，结晶线与熔融线平行。根据这些结果，我们建议在T _c的两端观察到的T _a和T _m之间的平行关系和内在相似性 范围可以归因于在结晶开始时形成的亚稳晶体。