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首页> 外文期刊>Journal of Applied Polymer Science >POLY(EPSILON-CAPROLACTONE)/POLY(ETHYLENE OXIDE) DIBLOCK COPOLYMER .1. ISOTHERMAL CRYSTALLIZATION AND MELTING BEHAVIOR
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POLY(EPSILON-CAPROLACTONE)/POLY(ETHYLENE OXIDE) DIBLOCK COPOLYMER .1. ISOTHERMAL CRYSTALLIZATION AND MELTING BEHAVIOR

机译：聚（ε-己内酯）/聚环氧乙烷二嵌段共聚物1。等温结晶和熔融行为

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The isothermal crystallization and melting behavior of the poly(epsilon-caprolactone) (PCL)/poly(ethylene oxide)(PEO) diblock copolymer has been studied by WAXD, SAXS, and DSC methods. Only the PCL block is crystallizable; the PEO block of weight fraction 20% cannot crystallize, although its corresponding homopolymer has strong crystallizability. The long period, amorphous layer, and crystalline lamella of the PCL/PEO block copolymer all increase with the rise in the crystallization temperature, and the thickness of the amorphous layer is much larger than that of crystalline lamella due to the existence of the PEO block in the amorphous region. The isothermal crystallization of the PCL/PEO block copolymer is investigated by using the theory of Turnbull and Fischer. It is found that the amorphous PEO block has a great influence on the nucleation of PCL block crystallization, and the extent of this influence depends on crystallization conditions, especially temperature. The outstanding characteristics are the phenomenon of the double melting peaks in the melting process of the PCL/PEO block copolymer after isothermal crystallization at different temperatures and the transformation of melting peaks from double peaks to a single peak with variations in the crystallization condition. They are related mainly to the existence of the PEO block bonding chemically with the PCL block. In summing up results of investigations into the crystallization and melting behavior of the PCL/PEO block copolymer, it is interesting to notice that when the PCL/PEO block copolymer crystallizes at three different crystallization temperatures, i.e., below 0 degrees C, between 0 and 35 degrees C, and above 35 degrees C, the variation of peak melting temperature is similar to that of overall crystallization rates in the process of isothermal crystallization. The results can be elucidated by the effect of the PEO block on the crystallization of the PCL block, especially its nucleation. (C) 1996 John Wiley & Sons, Inc. [References: 20]
机译：通过WAXD，SAXS和DSC方法研究了聚ε-己内酯（PCL）/聚环氧乙烷（PEO）二嵌段共聚物的等温结晶和熔融行为。只有PCL块可结晶。尽管其相应的均聚物具有很强的结晶性，但重量分数为20％的PEO嵌段不能结晶。 PCL / PEO嵌段共聚物的长周期，无定形层和结晶薄片都随结晶温度的升高而增加，并且由于存在PEO嵌段，无定形层的厚度比结晶薄片的厚度大得多在非晶区。利用Turnbull和Fischer理论研究了PCL / PEO嵌段共聚物的等温结晶。发现无定形PEO嵌段对PCL嵌段结晶的成核具有很大的影响，并且这种影响的程度取决于结晶条件，特别是温度。突出的特征是在不同温度下等温结晶后，PCL / PEO嵌段共聚物在熔化过程中出现双熔化峰的现象，并且随着结晶条件的变化，熔化峰从双峰转变为单峰。它们主要与PEO嵌段与PCL嵌段化学键的存在有关。在总结PCL / PEO嵌段共聚物的结晶和熔融行为的研究结果时，有趣的是，当PCL / PEO嵌段共聚物在三种不同的结晶温度（即低于0摄氏度，0至在35摄氏度和35摄氏度以上，等温结晶过程中的峰值熔融温度变化与总体结晶速率相似。可以通过PEO嵌段对PCL嵌段结晶，特别是其成核作用的影响来阐明结果。 （C）1996 John Wiley＆Sons，Inc. [参考：20]

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