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首页> 外文期刊>Journal of Applied Polymer Science >Crystallization behavior of poly(N-methyldodecano-12-lactam). IV. Nonisothermal crystallization
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Crystallization behavior of poly(N-methyldodecano-12-lactam). IV. Nonisothermal crystallization

机译：聚（N-甲基十二烷-12-内酰胺）的结晶行为。 IV。非等温结晶

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摘要

Nonisothermal crystallization of poly(Nmethyldodecano-12-lactam) (MPA) was investigated using DSC method at cooling rates of 2-40 K/min. With increasing cooling rate, crystallization exotherms decreased in magnitude and shifted toward lower temperatures. Subsequent heating runs (10 K/min) showed an exotherm just above T-g(,) which increased in magnitude with the rate of preceding cooling run, corresponding to the continuation of primary crystallization interrupted as the system crossed T-g on cooling. Kinetic evaluation by the Avrami method gave values of exponent n close to 2.0, suggesting two-dimensional crystal growth combined with heterogeneous nucleation. The Tobin method, covering the intermediate range of relative crystal-linities, provided n congruent to 2.20, suggesting possible partial in-volvement of homogeneous nucleation at later stages of nonisothermal crystallization. The crystallization rate parameter k(1) showed a linear dependency on cooling rate for both methods, the Tobin values being slightly higher. The Ozawa approach failed to provide reasonable values of the kinetic exponent m of MPA. The Augis-Bennet method was used to determine the effective activation energy of the entire nonisothermal crystallization process of MPA. (C) 2004 Wiley Periodicals, Inc.
机译：聚（Nmethyldodecano-12-lactam）（MPA）的非等温结晶采用DSC方法以2-40 K / min的冷却速率进行了研究。随着冷却速率的增加，结晶放热的幅度减小，并向较低温度转移。随后的加热运行（10 K / min）显示出刚好在T-g（）之上的放热，该放热的幅度随着先前冷却运行的速率而增加，这对应于随着冷却过程系统越过T-g，初次结晶的继续被中断。通过Avrami方法进行的动力学评估给出的指数n值接近2.0，这表明二维晶体生长与异质成核相结合。托宾法覆盖了相对结晶度的中间范围，提供了n等于2.20，表明在非等温结晶的后期阶段可能参与均相成核。两种方法的结晶速率参数k（1 / n）均与冷却速率呈线性关系，托宾值略高。 Ozawa方法无法提供MPA动力学指数m的合理值。使用Augis-Bennet方法确定MPA整个非等温结晶过程的有效活化能。 （C）2004年Wiley Periodicals，Inc.

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