Figure 11. Dielectric loss e" versus temperature at 30 Hz showing the segmental, the normal and the confinement-induced mode for thin PIP films I /V/, — 52,000g/mol) of different thicknesses, as indicated. |

Figure 19. Dielectric loss data of poly(isobutyl vinylether) RBVE at various combinations of temperature and pressure as indicated to demonstrate the invariance of the dispersion of the a-relaxation at constant a-loss peak frequency v or equivalently at constant a-relaxation time i . for three different i or the corresponding loss peak frequency v . Data supphed by G. Floudas [K. Mpoukouvalas, G. Floudas, B. Verdonck, and F. E. Du Prez, Phys. Rev. E 72, 011802 (2005).]. |

Figure 10. Dielectric loss data of diglycidyl ether of bisphenol-A (EPON828) at various combinations of temperature and pressure as indicated to demonstrate the invariance of the dispersion of the a-relaxation at constant a-loss peak frequency v or equivalently at constant a-relaxation time i . |

Figure 11a Evolution of the THz dielectric loss spectra stipulated by the rise of temperature (from bottom to top). Curves 1, 2,. .7 correspond to the temperatures 7i, 72,..., T7. The left column represents the same e"(v) loss spectra as shown in Fig. 10. The right column represents the loss contributions e" and e" pertinent to elastic longitudinal vibration (solid lines) and to elastic reorientation (dashed lines) of the H-bonded molecules. |

FIG. 11.3 Complex dielectric functions of poly(vinyl acetate). (A) Dielectric loss s"[T) as a function of temperature for three frequencies. (B) Temperature dependence of the dielectric constant s (v) (top panel) and the dielectric loss s"(v) (bottom panel) of the complex dielectric function curves from right to left in the temperature range from 377 to 313 K with steps of 4 K and 312.5,311.5,310.5,310 K. (C) 3D plot of the dielectric loss s"[ ,T). The author is much indebted to Prof. M. Wubbenhorst (KU Leuven) for his illustrative measurements on PVAC, especially for the benefit of this book. [Pg.328]

FIGURE 31.14 (a) Variation of the dielectric constant with temperature at different radiation doses, (b) Variation of the dielectric loss factor with temperature at different radiation doses. (From Banik, I., Chaki, T.K., Tikku, V.K., and Bhowmick, A.K., Angew. Makromol. Chem., 263, 5, 1998. With permission.) [Pg.903]

The dielectric loss spectrum at 293 K consists of the main microwave peak at 10 Hz (3.3 cm ) with a barely resolved shoulder at v ca 1.5x10 Hz corresponding to the maximum of the power absorption coefficient at v ca SO cm in the far infrared spectrum. If the measurement temperature is towered, the microwave loss peak, ascribed by the authors to p relaxation process, moves out ccmsidetably to lower frequendes and becomes resolved from the far infrared peak which is shifted with decreasing temperature in the opposite direction. [Pg.77]

Timofeeva, V.G., Borisova, T.L, Mikhailov, G.P., and Kozlov, P.V., Effect of supramolecular structure dissociation on the temperature maximum of dielectric losses of cellulose triacetate. In Cellulose and its Derivatives, Moscow AN SSSR Publ., 1963, pp. 174-180 (in Russian). [Pg.120]

For the frequency range 10-1000 cm-1 we present in Fig. 20a, b by solid lines the far-IR ice spectra of the absorption coefficient a(v) and of dielectric loss e"(v) calculated for the temperature — 7°C. The symbols V, T, L refer, respectively, to the V-, translational, and librational bands. The open circles mark the experimental data by Warren [49] these data are reproduced in Table IX. The fitted model and molecular parameters, used in this calculation, are given in Table X. [Pg.396]

The dielectric constant at 20°C increased from 3.39 to 3.84 due to the 1.7 %wt. moisture (2.0 %v.). The calculated increase of the dielectric constant from 3.39 to 3.60 is only about 50 % of the total effect. The Maxwell-Wagner theory thus seems to describe roughly the frequency/temperature location of the dielectric loss maximum due to absorbed moisture. However, it does not adequately describe the increase of the dielectric constant due to the moisture uptake from the air. A possible reason for this discrepancy might be that one of the assumptions does not hold, viz. that the conductivity of the resin matrix is negligibly small. [Pg.154]

Because the time of electron transit over a cluster from N particles is rN = Nxt it is easy to understand that in this model intensity of losses grows with reduction of a field frequency v down to value vum 1/2t2 and then remains constant. The temperature range for these dielectric losses is determined by a relationship between ti, t2, and xt and does not depend on a frequency of the electromagnetic field that is in accordance with experimental data. [Pg.564]

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