Dielectric α- and β-relaxations in uncured styrene butadiene rubber
The development of the dynamic glass transition in styrene-butadiene copolymers has been investigated by dielectric spectroscopy in the frequency range from 10-2 to 106 Hz. Two processes were detected and attributed to the α- and β-relaxations. The α relaxation time has a non-Arrhenius temperature b...
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| Autores principales: | , , , |
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| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00249297_v35_n11_p4337_Cerveny |
| Aporte de: |
| Sumario: | The development of the dynamic glass transition in styrene-butadiene copolymers has been investigated by dielectric spectroscopy in the frequency range from 10-2 to 106 Hz. Two processes were detected and attributed to the α- and β-relaxations. The α relaxation time has a non-Arrhenius temperature behavior that is highly dependent on styrene content while the β relaxation time shows an Arrhenius behavior with an activation energy that is independent of styrene-content. Furthermore, the shape of the α-relaxation is strongly influenced by the styrene content while the shape of β-relaxation is not. We interpret these results as follows. The observed β-relaxation is primarily due to local motions of butadiene monomers and therefore not affected by the presence of styrene. The α-relaxation, on the other hand, is highly sensitive to the styrene content due to its cooperative character. |
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