Abstract: In this paper, the dielectric property of PC and PE-LD melts were studied. For PC melt between 220 and 320 ℃, increasing temperature increased considerably the 10Hz dielectric constant, but marginally affect the values between 100 Hz and 1 000 Hz. For PE-LD melt between 120 and 300 ℃, the 10Hz dielectric constant first increased, then decreased and finally increased again, When the frequency was 1 000 Hz, the temperature had little influence on its dielectric constant. At low frequency zone, the dielectric constants of both melts decreased with increasing frequency.

Key words: polymer, melt, dielectric property, polycarbonate, low-density polyethylene