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| Titel: |
Dielectric Anisotropy in Die-drawn Isotactic Polypropylene Copolymer |
| Auteur: |
El-ghanem, H. M. Alkarmi, A. Jawad, S. Abdul |
| Verschenen in: |
International journal of polymeric materials |
| Paginering: | Jaargang 48 (2001) nr. 4 pagina's 477-488 |
| Jaar: |
2001 |
| Inhoud: |
The electrical behavior of die drawn isotactic polypropylene was investigated at room temperature in the frequency range 10 Hz to 106 Hz. The electric permittivity and electric modulus were determined from ac impedance measurements. In the low frequency range a dramatic increase in the imaginary and real components of dielectric permittivity was observed both parallel and normal to the chains alignment. This change is associated with a well defined relaxation peak in the plot of the imaginary component of electric modulus versus frequency. A high degree of anisotropy was observed in dielectric permittivity and electric modulus. This anisotropy is a result of chains alignment and the decrease in the mobility of molecules in the amorphous region due to the high constrains imposed on this region as a result of the drawing process. The Cole-Cole plot of the real component versus the imaginary component of electric modulus for both normal and parallel to the direction of chains alignment yields nearly perfect circles indicating that a certain polarization mechanism is dominant in die drawn isotactic polypropylene copolymer. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
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