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 - TY - JOUR A1 - Höpfner, Ulf A1 - Frübing, Peter A1 - Neumann, Werner A1 - Kaminorz, Yvette A1 - Brehmer, Ludwig T1 - Polarization Processes of poly(DMDAAC) films studied by TSD current Y1 - 1996 ER - TY - JOUR A1 - Yusupov, R. G. A1 - Frübing, Peter A1 - Brehmer, Ludwig A1 - Mislavski, B. V. T1 - Langmuir Filme des Polymers "NAFION" als sensibles Element eines Feuchtesensors Y1 - 1995 ER - TY - JOUR A1 - Brehmer, Ludwig A1 - Frübing, Peter A1 - Herkner, G. A1 - Kaminorz, Yvette T1 - Pyroelektrische Untersuchungen an dünnen Schichten von organischen Seitenkettenpolymeren Y1 - 1995 ER - TY - JOUR A1 - Penacorada, Florencio A1 - Yusupov, R. G. A1 - Milaski, B. A1 - Frübing, Peter A1 - Brehmer, Ludwig T1 - Elektrische Eigenschaften von polyionischen LB-Filmen Y1 - 1995 ER - TY - JOUR A1 - Frübing, Peter A1 - Grasnick, G. A1 - Herkner, G. A1 - Janietz, Dietmar A1 - Brehmer, Ludwig T1 - Pyroelektrische Untersuchungen an Polyvinylalkoholen mit Azobenzen / Alkoxy - Seitenketten Y1 - 1995 ER - TY - JOUR A1 - Wang, Feipeng A1 - Frübing, Peter A1 - Wirges, Werner A1 - Gerhard, Reimund A1 - Wegener, Michael T1 - Enhanced Polarization in Melt-quenched and Stretched Poly(vinylidene Fluoride-Hexafluoropropylene) Films N2 - beta-phase poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) copolymer films were prepared by uniaxially stretching solution-cast or melt-quenched samples. Different preparation routes lead to different amounts of the crystalline alpha and beta phases in the films, as detected by means of Fourier-transform infrared spectroscopy and X-ray diffractometry. The beta phase is significantly enhanced in melt-quenched and stretched films in comparison to solution-cast and stretched films. This is particularly true for copolymer samples with higher HFP content. The beta- phase enhancement is also observed in ferroelectric-hysteresis experiments where a rather high polarization of 58 mC/ m(2) was found on melt-quenched and stretched samples after poling at electric fields of 140 MV/m. After poling at 160 MV/m, one of these samples exhibited a piezoelectric d(33) coefficient as high as 21 pC/N. An electric-field-induced partial transition from the alpha to the beta phase was also observed on the melt-quenched and stretched samples. This effect leads to a further increase in the applications-relevant dipole polarization. Uniaxially stretched ferroelectric- polymer films are highly anisotropic. Dielectric resonance spectroscopy reveals a strong increase of the transverse piezoelectric d(32) coefficient and a strong decrease of the transverse elastic modulus c(32) upon heating from 20 to 50 degrees C. Y1 - 2010 UR - http://ieeexplore.ieee.org/servlet/opac?punumber=94 U6 - https://doi.org/10.1109/TDEI.2010.5539679 SN - 1070-9878 ER - TY - JOUR A1 - Frübing, Peter A1 - Kremmer, Alexander A1 - Gerhard, Reimund A1 - Spannoudaki, Anna A1 - Pissis, Polycarpos T1 - Relaxation processes at the glass transition in polyamide 11 : From rigidity to viscoelasticity Y1 - 2006 UR - http://jcp.aip.org/ U6 - https://doi.org/10.1063/1.2360266 SN - 0021-9606 ER - TY - JOUR A1 - Frübing, Peter A1 - Kremmer, Alexander A1 - Neumann, Werner A1 - Gerhard, Reimund A1 - Guy, I. L. T1 - Dielectric relaxation in piezo-, pyro- and ferroelectric polyamide 11 N2 - Ferroelectric polyamide 11 films were prepared by melt-quenching, cold-drawing and electrical poling. Their ferroelectricity was studied by means of dielectric-hysteresis measurements. A remnant polarisation of up to 35 mC/m(2) and a coercive field of 75 MV/m were obtained. The piezoelectric d(33) coefficient and the pyroelectric coefficient of the films are reduced by annealing just below the melting region, but remain at about 3 pC/N and 8 muC/(m(2)K), respectively, during further heat treatment. Differential scanning calorimetry (DSC), dielectric relaxation spectroscopy (DRS) and thermally stimulated depolarisation (TSD) were applied for investigating the conformational changes induced by melt-quenching, cold-drawing and annealing. The results indicate that the cold-drawn film mainly consists of a rigid amorphous phase which exhibits considerably lower conductivity, no glass transition and consequently no dielectric a relaxation. Instead, an a, relaxation is found, which is related to chain motions in regions of the rigid amorphous phase where the amide-group dipoles are not perfectly ordered. Annealing removes imperfectly ordered structures, but does not affect the ferroelectric polarisation. Therefore, it may be concluded that essentially the a, relaxation causes the thermally non-stable part of the piezo- and pyroelectricity in polyamide 11 Y1 - 2004 ER - TY - JOUR A1 - Frübing, Peter A1 - Krüger, Harald A1 - Goering, H. A1 - Gerhard, Reimund T1 - Relaxation behaviour of thermoplastic polyurethanes with covalently attached nitroaniline dipoles Y1 - 2002 ER -