Reorientational Dynamics of Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends by Broad-Band Dielectric Relaxation Spectroscopy

A comprehensive investigation of the reorientational dynamics of poly(vinylidene fluoride)/poly(methyl methacrylate) (PVDF/PMMA) blends was carried out. Dielectric relaxation spectroscopy (DRS) was performed over 11 decades of frequency and over a wide range of temperature on wholly amorphous, crystalline, and crystallizing blends of varying composition. The range of experimental conditions and compositional variables far exceeded those employed by previous investigators, enabling us to formulate a comprehensive view of the dynamics in these systems. A number of relaxation processes were detected, and their origins, temperature dependence, composition dependence, and spectral characteristics were established. Three α-type processes were observed: the αa process, associated with relaxations of all amorphous PVDF segments (not only within the crystalline−amorphous interphase); the αm process, which encompasses several relaxation processes and scales with blend composition; and the αc process, attributed to...