Low-temperature FT-NIR spectroscopy of strain-induced orientation and crystallization in a poly(dimethylsiloxane) network.

In: Macromolecular Rapid Communications, Jg. 26 (2005) ; Nr. 13, S. 1093-1098
ISSN: 1022-1336
Zeitschriftenaufsatz / Fach: Chemie
The mech. properties, morphol., and orientation of a poly(dimethylsiloxane) (PDMS) network have been studied during cyclic elongation and recovery by simultaneous Fourier-transform near-IR polarization spectroscopy at temps. ranging from room temp. to -40 DegC. 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 temp. The differences obsd. at -20 DegC compared to room temp. are explained in terms of conformationally regular chain segments, whereas the cooling to -40 DegC leads to the formation of lamellar crystals.