Dielectric investigation of polypropylene grafted with maleic anhydride

The blends of pure polypropylene and 3 wt% maleic anhydride grafted polypropylene have been investigated by means of dielectric and conductive spectroscopy. Since the blends are nearly nonpolar, they exhibit a very weak dielectric relaxation near room temperature associated with the glass transition. Linear relation between the relaxation strength and the maleic anhydride content allows an estimate of the dipole moment of maleic anhydride to yield 2.3D. The dc conductivity is found to become a minimum at 5 wt% grafted polypropylene. It is suggested that an introduction of a small amount of polar groups into a nonpolar polymer supply charge traps to reduce its conductivity