Abstract The crystallization process of crystalline polyester is one of the main processes in the process of machining and forming, and it is the key factor to determine the structures and properties of the final products。 In the further study of the theory and method of the crystallization kinetics of polyester has very important guiding significance for the characterization of the polyester material and the formulation of the forming process conditions。80619

Isothermal and non-isothermal crystallization kinetics of poly(cyclohexylene dimethylene cyclohexanedicarboxylate)(PCCE)were investigated via differential scanning calorimetry(DSC)。Isothermal melt crystallization kinetics of PCCE were analyzed using the traditional Avrami equation。An Avrami index close to three was obtained for PCCE,which implied growth of three-dimensional spherulitic superstructures following heterogeneous nucleation。Non- isothermal melt crystallization kinetics data obtained from DSC, first using the extended Avrami equation analysis。 This method is simple, but there is a lack of clear physical meaning about the crystallization rate constant。 Then using the combination of the Avrami equation and Ozawa equation, the results show that this method can be  used to analyze the non-isothermal crystallization process of PCCE。 These two methods are suitable for the fitting of  experimental  data,  and  they  are  all  proved  to  be  alternatives  to  the non- isothermal crystallization kinetics of PCCE。 However, the above two methods can not explain the non- isothermal crystallization kinetics based on the isothermal data。 In addition, the equilibrium melting point, isothermal crystallization activation energy and non- isothermal crystallization activation energy were determined。 The crystallization kinetic theory is explained in detail in the first chapter of the paper, and some other theories and methods are also described in this paper。

Furthermore, the original Nakamura equation was  not  successful  from  the  study  of non- isothermal crystallization kinetics of PCCE over a wide range of cooling rates。 Therefore, a predictive method based on Nakamura model was proposed, and this method was used to describe the non- isothermal crystallization kinetics based on the isothermal experimental data。 It  is  found  that the  predicted  results  were accurate。 Therefore, to  study the  non- isothermal

crystallization kinetics of PCCE over a wide range of cooling rate, it is better to described by modifying the differential Nakamura equation to include a varied of Avrami index。

Keywords: crystallization kinetics; PCCE (Poly(cyclohexylene dimethylene cyclohexanedicarboxylate)); differential scanning calorimetry; differential Nakamura model

摘要结晶性聚酯的结晶过程是在加工成形过程中结构演变的主要过程之一，是决定最终制品结构和性能的关键因素。深入研究聚酯的结晶动力学理论和方法，对聚酯材料的表征和成型加工条件的制定具有非常重要的指导意义。

本课题通过DSC法研究了PCCE的熔融行为和等温结晶与非等温结晶动力学。运用传统的Avrami方程很好地分析了PCCE的等温熔融结晶，得到的Avrami指数接近3，结果表明PCCE的球晶生长模式主要是伴随热成核的三维生长方式。非等温熔融结晶动力学数据由DSC法获得，先使用扩展的Avrami方程分析，这种方法虽然简单，但是得到的结晶速率常数缺乏明确的物理意义。再使用结合Avrami方程与Ozawa方程的方法来分析，结果发现该方法可以被用来分析PCCE的非等温结晶过程。这两种方法均适用于实验数据的拟合，并且它们都被证明是描述PCCE非等温结晶过程结晶动力学的好的备选方法。然而，上述两种方法都不能解释等温结晶数据基础上的非等温结晶动力学。另外，平衡熔点、等温结晶活化能和非等温结晶活化能被测定。以上使用的结晶动力学理论在论文第一章的叙述中都有详细解释，另外还有一些这方面其它的理论和方法的讲述。