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Pathway-Dependent Melting in a Low-Molecular-Weight Polyethylene-block-Poly(ethylene oxide) Diblock Copolymer

✍ Scribed by Lu Sun; Yuxiu Liu; Lei Zhu; Benjamin S. Hsiao; Carlos A. Avila-Orta


Publisher
John Wiley and Sons
Year
2004
Tongue
English
Weight
125 KB
Volume
25
Category
Article
ISSN
1022-1336

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✦ Synopsis


Abstract

Summary: In a low‐molecular‐weight polyethylene‐block‐poly(ethylene oxide) (PE‐b‐PEO) diblock copolymer, two pathway‐dependent melting processes were observed: Upon slow heating, the PE lamellar crystals melted at ≈97 °C into a disordered state. However, when the temperature rapidly jumped to above the melting point (e.g., 100 °C), the PE lamellar crystals transformed directly into an ordered lamellar melt, followed by an isothermal conversion into a disordered melt. This isothermal order‐to‐disorder transition was explained by superheating of the PE crystals using a GT diagram.

A schematic GT diagram explaining the pathway‐dependent double melting for a crystalline polyethylene‐block‐poly(ethylene oxide) copolymer.

imageA schematic GT diagram explaining the pathway‐dependent double melting for a crystalline polyethylene‐block‐poly(ethylene oxide) copolymer.