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2H NMR Study of Aromatic Guest Dynamics in Clathrate Phases of Syndiotactic Polystyrene



Summary:2H NMR solid-state spectra of aromatic molecules (benzene, toluene, chlorobenzene, naphthalene) included in clathrate phases of syndiotactic polystyrene (s-PS) or absorbed in the amorphous phase of s-PS, have been recorded and analyzed for a broad range of temperature (230–360 K). The dynamic processes accessible to aromatic molecules absorbed in s-PS clathrate phases are essentially temperature independent for the whole temperature range under investigation. Moreover, the molecular re-orientations reflected in the NMR line-shapes are similar to those accessible to the same molecules when absorbed in polystyrene amorphous phase at temperatures substantially lower than the polymer glass transition temperature. A simulation procedure for 2H NMR line-shape analysis has been used to establish models for the dynamic processes of the different aromatic guest molecules.

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Solid-state 2H NMR spectrum of naphtalene-d8 in the amorphous phase of a semi-crystalline s-PS film (A), in the s-PS clathrate phase (B) and the simulated spectrum for a static C[BOND]D bond (C).