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Low-Temperature FT-NIR Spectroscopy of Strain-Induced Orientation and Crystallization in a Poly(dimethylsiloxane) Network

✍ Scribed by Evgueni Klimov; Günter G. Hoffmann; Alexander Gumenny; Heinz W. Siesler


Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
162 KB
Volume
26
Category
Article
ISSN
1022-1336

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✦ Synopsis


Abstract

Summary: The mechanical properties, morphology, and orientation of a poly(dimethylsiloxane) (PDMS) network have been studied during cyclic elongation and recovery by simultaneous Fourier‐transform near‐infrared polarization spectroscopy at temperatures ranging from room temperature to −40 °C. Completely different orientation/recovery mechanisms and changes in the state of order of PDMS were detected as a consequence of cyclic loading/unloading with decreasing temperature. The differences observed at −20 °C compared to room temperature are explained in terms of conformationally regular chain segments, whereas the cooling to −40 °C leads to the formation of lamellar crystals.

Stress/strain diagrams of the elongation/recovery‐cycles of the PDMS films.

magnified imageStress/strain diagrams of the elongation/recovery‐cycles of the PDMS films.