Influence of melt stretching process on POK dielectric properties and relaxation behavior

The dielectric properties and relaxation behaviors of POK films with different melt draw ratios were investigated. The dielectric constant of the sample increases to 11.1 (1 kHz) after melt stretching. The molecular chain orientation induced by melt stretching reduces the thermodynamic relaxation temperature, but the well-aligned lamellae restrict the movement of amorphous chains. The dielectric relaxation of the crystalline region and the amorphous region is inconsistent, and the dipole relaxation in crystalline region is obviously weaker than that of the amorphous region. After melt stretching, the activation energy of dipole motion perpendicular to the oriented molecular chains decreases, resulting in an increase in the dielectric constant of POK films with increasing melt stretching ratio.

Automated summary

The dielectric properties and relaxation behaviors of POK films with different melt draw ratios were studied. Results showed that melt stretching affects the molecular chain orientation and structure, and influences the dielectric performance of the films. Inconsistent dielectric relaxation was observed between the crystalline and amorphous regions.