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The Isothermal Melting Kinetics of Ultrahigh Molecular Weight Polyethylene Crystals.

Jianwei XueYaguang LuBinghua WangJingbo ChenChangyu ShenBin Zhang
Published in: Macromolecular rapid communications (2024)
The isothermal melting behaviors of ultrahigh molecular weight polyethylene (UHMWPE) with different entangled states (i.e., nascent and melt-crystallized samples) have been studied. For two kinds of UHMWPE samples, our result shows that the relative content of survived crystals (X s ) exponentially decreases with time and reaches a constant value. We suggest that such a melting behavior is related to the observed nonlinear growth of crystals induced by the kinetically rejected entanglements accumulated at the growth front. Additionally, the exponential decay of X s with time provides a characteristic melting time (τ) for the melting process. Compared to the melt-crystallized UHMWPE, the τ value of nascent UHMWPE is generally longer even in a higher temperature range, which is mainly because the former has a larger entanglement density difference. Furthermore, our observations demonstrated that UHMWPEs with different entangled states have an analogous melting mechanism since they exhibit a similar melting activation energy (∼1300 kJ/mol). This article is protected by copyright. All rights reserved.
Keyphrases
  • high resolution
  • mass spectrometry
  • room temperature