TY  - JOUR
A1  - Raman Venkatesan, Thulasinath
A1  - Gulyakova, Anna A.
A1  - Frübing, Peter
A1  - Gerhard, Reimund
T1  - Electrical polarization phenomena, dielectric relaxations and structural transitions in a relaxor-ferroelectric terpolymer investigated with electrical probing techniques
JF  - Materials research express
N2  - Dielectric Relaxation Spectroscopy (DRS) and Thermally Stimulated Depolarization Current (TSDC) measurements were employed to study dielectric-relaxation processes, structural transitions and electric-polarization phenomena in poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer films. Results from DRS confirm the existence of two separate dispersion regions related to a para-to-ferroelectric phase transition and to the glass transition. The dipolar TSDC peak correlates with the loss peak of the ? relaxation that represents the glass transition. The electric polarization calculated from the dipolar TSDC peak (glass transition) shows a non-linear electric-field dependence and saturates at high electric poling fields. As the observed behaviour is essentially the same as that of the electric polarization obtained from direct polarization-versus-electric-field hysteresis measurements, TSDC experiments are also suitable for studying the polarization in relaxor-ferroelectric polymers. A saturation polarization of 44 mC m(?2) was found for an electric field of 190 MV m(?1).
KW  - P(VDF-TrFE-CFE) terpolymer
KW  - relaxor-ferroelectric polymers
KW  - dielectric relaxation spectroscopy
KW  - thermally stimulated depolarization current
KW  - electrical polarization hysteresis
Y1  - 2019
U6  - https://doi.org/10.1088/2053-1591/ab5352
SN  - 2053-1591
VL  - 6
IS  - 12
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Guliakova, A. A.
A1  - Gorokhovatsky, Yu. A.
A1  - Galikhanov, M. F.
A1  - Frübing, Peter
T1  - Thermoactivational spectroscopy of the high impact polystyrene based composite films
T1  - Термоактивационная спектроскопия композитных полимерных пленок на основе ударопрочного полистирола
JF  - St. Petersburg Polytechnic University Journal : Physics and Mathematics
N2  - The relaxation processes in the high impact polystyrene (HIPS) films filled with 2, 4, 6 vol.% of titanium dioxide (TiO2) of the rutile modification have been studied using the thermally stimulated depolarization current (TSDC) technique. Three relaxation processes were observed in the composite HIPS films. The first one (a-relaxation peak) appeared at about 93 degrees C and represented the glass transition. The second peak p was a high-temperature part of the first one and overlapped it. The p peak was caused by the release and subsequent motion of excess charges deposited during the electret preparation or the polarization process. The third peak appeared at about 150 degrees C and occurred only in the spectra of the composite films. The overlapping peaks were separated by the thermal cleaning technique. The subsequent application of the numerical methods (the Tikhonov regularization technique) allowed to determine the activation energy of the second process and to compare the obtained value with the corresponding data on the dielectric relaxation.
N2  - С помощью метода токов термостимулированной деполяризации (ТСД) исследованы релаксационные процессы в пленках ударопрочного полистирола (УПС) без наполнителя и с различным содержанием диоксида титана TiO2 (2, 4, 6 об.%). На кривых тока ТСД, полученных для композитных пленок, обнаружено три пика. Первый (α-релаксация) возникает при температуре около 93 °C и соответствует переходу вещества из стеклообразного состояния в высокоэластическое. Второй (ρ-пик) появляется как высокотемпературное плечо α-пика и соответствует процессу высвобождения и движения избыточных носителей заряда. Наличие третьего пика при температуре около 150 ºС характерно только для композитных пленок УПС. Разделение перекрывающихся α- и ρ-пиков проведено методом частичной термоочистки. Последующее применение регуляризующих алгоритмов Тихонова позволило определить энергию активации второго процесcа и сравнить полученное значение с результатом, полученным методом диэлектрической спектроскопии.
KW  - thermoactivational spectroscopy
KW  - high impact polystyrene
KW  - titanium dioxide
Y1  - 2019
U6  - https://doi.org/10.18721/JPM.12401
SN  - 2405-7223
SN  - 2618-8686
SN  - 2304-9782
VL  - 12
IS  - 4
SP  - 9
EP  - 16
PB  - Elsevier
CY  - Amsterdam
ER  -