Dielectric Relaxation Behavior Studies in Amorphous Terpolymer of Poly(Vinyl Chloride-co-Vinyl Acetate-co-2-Hydroxypropyl acrylate) Using Dielectric Spectroscopy and Thermally Stimulated Current Techniques

Abstract

Dielectric studies on random terpolymer of poly(vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) have been carried out. The dielectric techniques used include broadband ac dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarization current (TSDC) techniques. TSDC technique enables us to observe the primary α-relaxation, which is associated with the glass transition temperatutre, and the space charge relaxation. The peak parameters value of α-relaxation, namely, the activation energy E a and the preexponential factor τ 0, have been evaluated and found to be 1 eV and 3 × 10−11 s, respectively. The variation of the dielectric properties with frequencies and temperatures has been related mainly to two processes: (i) the α-relaxation and (ii) the conductivity relaxation. Electric modulus representation shows two peaks, namely, the α-relaxation and conductivity relaxation. The dielectric data were fitted to Havriliak–Negami (HN) relaxation model, and the shape parameter values suggest a broad and an asymmetric distribution of relaxation time. The activation energy value (˜1 eV) of the α-relaxation, obtained from electric modulus representation, was found to be the same as that obtained from TSDC measurements.