Influence of charging parameters on piezoelectricity for cellular PP film electrets

The influence of charging parameters (such as charging voltage, charging time and charging temperature, etc.) on piezoelectricity and its thermal stability of cellular polypropylene film electrets was studied by means of contact charging and constant voltage corona charging methods and the thermal stimulated discharge technique. The cause of the influence is discussed in connection with the structure and the theoretic model of the cellular piezoelectric film electrets, and its dynamic characteristic of space charge is also analyzed. The results show that the piezoelectricity and its thermal stability of these electrets may be improved by optimizing the charging parameters.It is hoped that this work will be helpful to widen the application of cellular PP and will offer theoretic and technical basis for its industrialization.