Two resolved dielectric absorption peaks of the 1-bromoalkanes

Abstract

Dielectric absorption studies have been made on numerous 1-bromoalkanes in the frequency range 10–10⁵ Hz and in the temperature range 80–300 K. The 1-bromoalkanes have been dispersed mainly in a polystyrene matrix, although a few have been examined in polypropylene and glassy o-terphenyl as well. In the polystyrene matrix a loss-factor against temperature plot at a fixed frequency clearly reveals two well separated absorption peaks. The data may be successfully analysed in terms of a model which involves a molecular relaxation process (governed by a µ_m moment) and segmental motion involving movement of the —CH₂Br portion (characterized by a µ_s moment). The extrapolated values of µ_m and µ_s at 330 K lead to an effective dipole moment in reasonable agreement with literature values.