Structural analysis of PPX prepared by vapor phase pyrolysis of [2.2]paracyclophane

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Schmidt, C. ; Stümpflen, Volker ; Wendorff, Joachim H. ; Hasenhindl, A. ; Gronski, W. ; Ishaque, Michael ; Greiner, Andreas:
Structural analysis of PPX prepared by vapor phase pyrolysis of [2.2]paracyclophane.
In: Acta Polymerica. Bd. 49 (1998) Heft 5 . - S. 232-235.
ISSN 1521-4044
DOI: https://doi.org/10.1002/(SICI)1521-4044(199805)49:5<232::AID-APOL232>3.0.CO;2-L

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Abstract

Poly(p-xylylene) (PPX) was prepared by vapor phase pyrolysis of 2.2]paracyclophane following the procedure of Gorham. PPX was obtained in different crystalline modifications by dry annealing, dissolution and reprecipitation under different conditions. These samples were analyzed by WAXS and C-13 CP-MAS NMR spectroscopy. Clear evidence was found that the presence of different crystalline modifications is responsible for the unexpected C-13 CP-MAS NMR spectrum as observed for as-polymerized PPX. An attempt was made to explain the differences observed in the C-13 CP-MAS NMR spectra of different crystalline modifications by different chemical environments utilizing simulations of the crystal unit cells.