synopsisMeasurements of complex shear compliance (J* = J'd") as functions of frequency and temperature for an unvulcanized sample of a butadiene terpolymer are presented. The me* surements reveal the existence of a broad retardation dispersion at audio frequencies and temperatures between -30" and +35"C; but at temperatures below 0' and above 24"C, there are superimposed several series of sharp resonance dispersions. The appearance of these fine spectra below 0" and above 24°C correlates well with observed transitions in specific volume-temperature curves for the material at 1' and 24.5OC. Analyses of the spectra a t 35.7"C reveal four separate spectral series each with mode frequencies increasing as 1, 4, 9, 16, . . ., etc. in agreement with predictions of the momentum-wave description of nonelastic deformation. Further, the ratios of frequencies for a common mode are in good agreement with the inverse atomic mass ratios of the atoms or atomic group to which each series is assigned. Thus, for the first mode of each series a t 35.7"C, the frequency ratios are 1.000: 1.142: 1.220: 1.335 for modes assigned to oxygen, nitrogen, the CH group, and carbon. These ratios, in turn, are in good agreement with the inverse atomic mass ratios, 1.000: 1.142: 1.230: 1.333, as expected from momentum-wave deformation theory. Examination of the microstructural and stress requirements for observation of nonelastic resonances in vibration experiments suggests that some type of one-dimensional order extending over about 6 micrometers is present in the terpolymer below 0" and above 24OC, but is absent between these temperatures. The successful explanation of the dynamic mechanical behavior of this terpolymer, together with previous results cited for other materials, indicates the usefulness of the momentum-wave theory of mechanical deformation in correlating microstructure and macroscopic mechanical response.
