Abstract
ABSTRACT In this work, the electrical prporties of Poly Methyl Meth Acrylates (PMMA) has been studies under the application of direct and alternating electrical field at different temperature. Morever conduction mechanism in direct field were investageted. The current voltage characterstic for PMMA sample has been studies at different temperature. The results show that the current leakage increases as the applied voltage and temperature increase. It was also found three regions appeared in the I-V characterstic with different slops, their values approxametaly equal (1, 2 and 23) respectivly. Accordingly, one can say the conduction mechanism in this study is space charge limited current (sclc). The breakdown voltage were found for the sample at temperature 20Cº, 40Cº, 60Cº and 90Cº equal to 2000V, 1200V, 1600V and 1500V respectivly. The study of dielectric properties of PMMA has been done by measuring the capacitance and conductance as a function of frequency. The experimetal results show that dielectrical constants( ), dielectrical loss ( ) and loss tangent (tan ) decreases as the frequency increases. While their values increases the temperature increases. The variation of loss tangent with frequency as show that the peak frequency was shifted to higher frequencies with an increase of temerature.
