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Phase transition from a C‐centered to a B‐centered orthorhombic crystalline form of syndiotactic poly(propylene) by Finizia Auriemma; Russell H. Lewis; Hans Wolfgang Spiess; Claudio De Rosa is a Materials Science article available to read on EtoBox.

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## Abstract Samples of highly syndiotactic poly(propylene) (s‐PP) crystallized in a C‐pseudo‐centered orthorhombic form are here characterized through high resolution solid state ^13^C NMR sepctroscopy and wide angle X‐ray diffraction. The ^13^C NMR CP MAS (cross‐polarization, magic angle spinning) spectra of highly disordered quench‐precipitated s‐PP samples (with a structure very close to a C‐pseudo‐centered orthrohombic form) yield additional resonances beside those already reported in the literature for s‐PP samples crystallized with the chains in a fully helical \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} (TTGG\rlap{--} )\_n $\end{document} conformation (T: __trans;__ G: __gauche__). From the correlation of ^13^C NMR CP MAS spectra with the X‐ray diffraction profiles recorded at the same temperatures, it is possible to establish that at a given temperature (approximately 100°C, for our samples) a phase transition from the C‐ to the B‐pseudo‐centered orthorhombic form starts to occur. Correspondingly, the aforementioned additional resonances in the ^13^C NMR CP MAS spectra progressively disappear with the onset of the phase transition. These extra resona

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Author

Finizia Auriemma; Russell H. Lewis; Hans Wolfgang Spiess; Claudio De Rosa

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Ltd.; Wiley (ISSN 1022-1352)

Published

1995

Language

EN

Field

Materials Science (Physical Sciences)