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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 23, Number 3
BKCSDE 23(3)
March 20, 2002 

 
Title
Dielectric Relaxation of Siloxane-Epoxy Copolymers
Author
Chy Hyung Kim, Jae Sup Shin
Keywords
Dielectric relaxation, Temperature-frequency superposition, Shifting factor, Cole-Cole, WLF relation.
Abstract
The dielectric responses of 10 and 40 wt% siloxane-epoxy copolymers were investigated in temperature range near the glass transition of polydimethylsiloxane at which the dielectric transitions were also observed. On the other hand, the pure epoxy did not show any dielectric transition in measurement temperature range -90 to 150 ℃. The experimental data showed that for the copolymer investigated, the temperature-frequency super-position principle could be applied to the dielectric response. From the Cole-Cole equation, the dielectric relaxation of the 10 wt% siloxane near the glass transition temperature resulted in a broad distribution with β= 0.19 and the relaxation time at -70 ℃ was 5.3 × 10-2 s. The glass transition temperature, 188 K, was estimated by using WLF relation, which was consistent with the data presented in experiment.
Page
413 - 416
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