Effect of catalysts on thermally stimulated current in poly(ethylene terephthalate)

The effect of catalysts on relaxation phenomena in poly(ethylene terephthalate) (PET) was studied by thermally stimulated current (TSC). Resins Sb-PET and Ge-PET were produced by the antimony and germanium main catalyst systems, respectively. Spontaneous, global and thermal sampling of TSC were compared in both PETs. The lower TSC peaks are observed in Ge-PET than those in Sb-PET for equivalent treatment. The compensation parameters were determined from the variation polarization temperatures (T-p) data. These parameters were used to calculate degree of disorder (DOD). The DOD of Sb-PET and Ge-PET were 36.14 and 66.23, respectively. The relaxation time at the maximum current and the dipolar relaxation strength in the Sb-PET has the higher values and wider distribution than that in Ge-PET. Furthermore, Sb-PET exhibited electrically softer. These results are attributed to the stiffening amorphous parts by the entanglement network in Ge-PET.