کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5186465 | 1381105 | 2009 | 6 صفحه PDF | دانلود رایگان |
The crystallinity of poly(butylene terephthalate) (PBT) films was investigated by comparing measurements of fluorescence and density. It was found that the ratio of the fluorescence intensity at 320Â nm to that at 365Â nm can be an effective indicator of crystallinity. The dynamic process of cold crystallization was directly observed for PBT films prepared using a spin-casting method on quartz disks by means of fluorescence measurements at several temperatures between 360 and 400Â K. The cold crystallization of such films was found to proceed one-dimensionally under the mechanism of heterogeneous nucleation, since the Avrami exponent, n, was determined to be one. The apparent activation energy of cold crystallization was determined to be 24Â kJ/mol, indicating that rotation around carbon-carbon bonds in a butylene unit of PBT participates in reorientation and crystallization. The present work should provide a quick and nondestructive method for determining the crystallinity of PBT factory products.
Journal: Polymer - Volume 50, Issue 6, 6 March 2009, Pages 1491-1496