Improving electric thermal stability of polypropylene by chemically linking small amount of hindered phenol groups

Thermal stability of polypropylene (PP) over a broad temperature is critical for many applications. Hindered phenol (HP) groups have been utilized in PP for thermal-oxidative protection. This paper studies thermal stability of the electret property of PP linked with 0.2 mol% HP. It is observed that small amount of chemically linked HP groups improves electret thermal stability as reflected by the higher peak temperature of the thermally stimulated discharge curve and about 65% increase in the trap level. In addition, the HP groups in PP generate “rigid backbones” which maintain the PP film shapes to temperatures near the melting (~ 150 °C), compared with pristine PP at 70 °C.