Nonlinear Electrical Behavior Investigation of New ZnO-Polythiophene- Polyethylene Composites
Sajedeh Mohammadi Aref,
Background: ZnO-based varistors are used as surge protectors in electrical circuits. Nonlinear
polymer composites are attractive because of their potential applications in low voltage varistors.
The aim of this research is to study nonlinear behavior in a new composite containing ZnO,
polythiophene and polyethylene.
Methods: Sample disks consist of 70 wt% ZnO and 30 wt% polymer matrixes were prepared using
the hot press method under 20 MPa at 120 ºC. I-V characteristics of the disks were studied by applying
DC voltage. The structure of the products was examined by FESEM and X-ray diffraction.
Results: I-V characteristics of the disks show that their resistivity varies nonlinearly under different
voltage. By increasing polythiophene content in sample disks, their breakdown voltage decreases
whereas nonlinear coefficient increases. On the other hand increasing press temperature has the same
effect on the breakdown voltage and nonlinear coefficient. In addition, each increase in working
temperature leads to lower breakdown voltage and nonlinear coefficient.
Conclusion: Polymer composite containing 70% ZnO-6% polyethylene-24% polythiophene has an
appropriate nonlinear behavior. An increase in press temperature enhances nonlinear coefficient and
reduces breakdown voltage. FESEM images of the samples show pressing samples at 120 ºC does
not affect composite structure.
Keywords: Composite varistor, Hot press, Nonlinear behavior, Polythiophene, Zinc oxide.
Rights & PermissionsPrintExport