Ru-doped phosphazene membrane materials used for catalytic hydrogenation

Semicrystalline polydimethylphosphazene [-N=P(CH3)2-]N (PDMP) and the catalyst Ru-doped PDMP, in both the virgin and hydrogenated forms, have been analysed using differential scanning calorimetry spectroscopy (DSC), 31P magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction (XRD) and positron annihilation lifetime spectroscopy (PALS). These techniques in combination indicate that the catalyst Ru coordinates the polymer and alters the structural conformation of the polymeric chain. The PALS data show that this coordination induces structural ordering that results in a decrease in the size of the inter- and intra-chain spacing. This ordering is also evidenced by a decrease in the intensity of the 31P upfield resonance, an increase in Tg and the appearance of a pre-melting endotherm.