DIELECTRIC-PROPERTIES OF POLY[BIS(TRIFLUOROETHOXY)PHOSPHAZENE] AND POLY[BIS(M-METHYLPHENOXY)PHOSPHAZENE]

Dielectric properties of Poly[bis(trifluoroethoxy)phosphazene] (PFEP) and poly[bis(m-methylphenoxy)phosphazene] (PmMPP) were studied in a te mperature range from -195 to 120-degrees-C and at several frequencies between 0,1 and 100 kHz. In PFEP, two relaxations, an a relaxation abo ve the glass transition temperature (T(g)) and a beta relaxation below T(g), which are related to a glass-rubber transition and a local mole cular motion of short segments, respectively, were observed. However, PmMPP shows no beta relaxation. From the above dielectric results, it was concluded that side groups play an important role in molecular mot ion of the polyphosphazenes. In PmMPP a gamma' relaxation was found be low T(g) by immersing the polymers into water. The gamma' relaxation i s related to the molecular motion of absorbed water.