Dielectric properties of polystyrene and some polychlorostyrenes from 4°K to room temperature

Abstract

synopsisDielectric measurements of carefully purified specimens of polystyrene and poly(2,3,4 or 3,4-chlorostyrene) have been obtained at audio frequencies ranging from 0.1 to 20 kHz and a t temperatures between 4 and 300°K. Each of the samples exhibits a dielectric loss maximum in the range 13-50°K. The temperature of the maximum loss decreases with the addition of a substituent which lowers the symmetry of the pendant phenyl group. The results are explained by a model which invokes a coupling mechanism between two distinct modes of side group motions. This same model also explains some results of previously reported measurements of mechanical losses in similar polymers.

Thermal contraction and volume relaxation of amorphous polymers

“…Sinnott [14] (38 K, 6 Hz), Yano and Wada [15] (70 K, 34kHz and 81 K, 152kHz) and Hartwig [12] (40K, 10 Hz mechanically, 40 K, 50 Hz dielectrically). This process is attributed to reorientation and wagging of the phenyl group [16,17]. In dilatometric investigations, it is overshadowed by the sharp decrease in c~ due to the third law effect.…”

Structure and properties of microwave transparent crosslinked polystyrene prepared through 3D printing bulk polymerization

“…This may be the outcome that the relaxation dispersion for pendent phenyl groups of PS has been shifted to higher band after crosslinking, although it was not entirely detected right in the investigated frequency range. Many people have conducted researches on the dielectric properties of PS . It was claimed that the dielectric loss of PS at MW band is mainly contributed by the very small amplitude torsional oscillation of phenyl groups.…”

“…Many people have conducted researches on the dielectric properties of PS. 31,32 It was claimed that the dielectric loss of PS at MW band is mainly contributed by the very small amplitude torsional oscillation of phenyl groups. Therefore, with respect to the fact that the crosslinking with DVB was carried out on main-chains, there should be underlying relationship through which the influence of constraint on a relaxation behavior has extended to the b relaxation of side groups.…”

Measuring the permittivity and permeability of lossy materials :

“…• Measurements on plastics are given in References [9,[161][162][163][164][165][166][167][168][169][170][171][172].…”