Melt Memory Effect beyond the Equilibrium Melting Point in Commercial Isotactic Polybutene‑1

The memory effect denotes acceleration of crystallization kinetics in polymers when being cooled from the molten state. Using the method of differential scanning calorimetry (DSC), we found that a commercial isotactic polybutene-1 (i PB-1) sample showed a unique melt memory effect. Even though the i...

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Veröffentlicht in:Industrial & engineering chemistry research 2019-04, Vol.58 (14), p.5472-5478
Hauptverfasser: Liu, Peiru, Xue, Yanhu, Men, Yongfeng
Format: Artikel
Sprache:eng
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Zusammenfassung:The memory effect denotes acceleration of crystallization kinetics in polymers when being cooled from the molten state. Using the method of differential scanning calorimetry (DSC), we found that a commercial isotactic polybutene-1 (i PB-1) sample showed a unique melt memory effect. Even though the iPB-1 sample was molten at the temperature (T ms) higher than the equilibrium melting point of iPB-1 (133 °C), the memory effect was still observed, which affected the subsequent crystallization behavior. Briefly speaking, the total crystallization rate increased greatly with the decrease of T ms. Moreover, the lower the preparation temperature, the faster it can crystallize. However, the melt memory effect beyond the equilibrium melting point disappeared after purifying this commercial sample. The results reveal that the increase of crystallization rate is directly related to the increased density of iPB-1 nuclei originated from some additives remaining in the melt. Only if T ms is higher than 165 °C, much higher than 133 °C, does the influence of additives vanish and the crystallization rate of iPB-1 reach a constant value.
ISSN:0888-5885
1520-5045
DOI:10.1021/acs.iecr.8b06444