Dielectric Analysis DEA

Smith et al. [1.127 ] reviewed dielectric relaxation spectroscopy (DRS) as a method for the structural characterization of polymers and proteins providing, among others, information about the water content and states of water. 

AGLAIA VASSILIKOU-DOVA and lOANNIS M. KALOGERAS Department of Solid State Physics, Faculty of Physics, University of Athens, Panepistimiopolis, Greece 

Thermal Analysis of Polymers Fundamentals and Applications, Edited by Joseph D. Menczel and R. Bruce Prime 

Establishment of Relationships between a Polymer s Configuration, Dynamic Properties, and Applications 

Information on Surface and Bulk Properties in Confining Environments 

Online Monitoring of Chemical Reactions (Poiymerization, Curing), Physical Processes (e.g., Aging), and Structure Formation 

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Dielectric analysis (DEA) measures the electrical properties of a material as it is subjected to a periodic electric field under various conditions. This technique provides quantitative information on the capacitance and conductance of the ma-... 

Morris et al. [1.126] proposed to use dielectric analysis (DEA) to predict the collapse temperature of two component systems. The background of DEA is explained and the take off frequency (TOF) is chosen as the best analytical method to identify the collapse temperature. Figure 1.55.5 shows the dielectric loss factor as a function of the frequency. 

Morris et al. [1.126] proposed the use of dielectric analysis (DEA) to predict the collapse temperature of two-component systems. The background of DEA is explained and the >take-off frequency< (TOF) is chosen as the best analytical method to identify the collapse temperature. Figure 1.55.5 shows the dielectric loss factor as a function of the frequency. The frequency at the minimum of this curve is called TOF by the authors. TOF varies with the temperature as shown in Figure 1.55.6. The extrapolated intersection of the two linear portions identifies the collapse temperature. The predicted Tc by TOF for 10% sucrose, 10% trehalose, 10% sorbitol and 11% Azactam solution deviates from observations with a freeze-drying microscope (Table 1 in [1.126]) to slightly lower temperatures, the differences being -3, -1.4, 2.2 and 0.7 °C. 

For non-elastomeric thermosets, Carrasco [13] described the use of DSC to follow the conversion during cure of a trifunctional aminoepoxy resin. Here, the conversion was determined versus a non-cured sample. Sauerbrunn [14] also described the use of DSC to follow fiiermoset curing amongst other applications. Stephan [15] utilized dielectric analysis (DEA) as well as DSC, viscosity measurements and insolubles analysis to follow the curing, cure state and... 

In this paper, we analyze the effect of fluorine substitution in the polymers listed above by dielectric analysis (DEA), dynamic mechanical analysis (DMA) and stress relaxation measurements. The effect of fluorination on the a relaxation was characterized by fitting dielectric data and stress data to the Williams, Landel and Ferry (WLF) equation. Secondary relaxations were characterized by Arrhenius analysis of DEA and DMA data. The "quasi-equilibrium" approach to dielectric strength analysis was used to interpret the effect of fluorination on "complete" dipole... 

Dynamic mechanical (DMA) and dielectric analysis (DEA) methods are used both to study molecular relaxation processes in polymers and to determine inherent... 

Dielectric analysis (DEA) measures changes in the properties of a polymer as it is subjected to a periodic (or alternating) electric field. In DEA a sample is placed between two electrodes. The traditional electrode geometry used for thermoplastics is a parallel-plate capacitor. The parallel-plate electrode measures the bulk dielectric response of the material subjected to a sinusoidal voltage applied to the electrodes. The electrodes typically are formed by vapor deposition or sputtering of a metal onto the polymer surfaces. A more contemporary dielectric electrode geometry is the interdigitated comb type of electrode which is particularly well... 

Dielectric analysis (DEA) has the capability for following the transformation of a thermoset from a low molecular weight liquid resin to a solid cross-linked network. 

Van Eerdenbrugh B, Taylor LS (2011) AppUcation of mid-IR spectroscopy for the characterization of pharmaceutical systems. Int J Pharm 417 3-16 Vassilikou-Dova A, Kalogeras IM (2008) Dielectric analysis (DEA), thermed tmtilysis of polymers. Wiley, pp 497-613... 

Thermal analysis (TA) comprises a family of measuring techniques that share a common feature they measure a material s response to being heated or cooled (or, in some cases, held isothermally). The goal is to establish a connection between temperature and specific physical properties of materials. The most popular techniques are those that are the subject of this book, namely differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), dynamic mechanical analysis (DMA), dielectric analysis (DEA), and micro/nano-thermal analysis (p/n-TA). 

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