Dielectric Analysis

2019 ◽  
pp. 203-216
Author(s):  
Ana Catarina Lima ◽  
C.M. Costa ◽  
S. Lanceros-Méndez
Keyword(s):  
Dielectric Analysis

scholarly journals Cure Kinetics Modeling of a High Glass Transition Temperature Epoxy Molding Compound (EMC) Based on Inline Dielectric Analysis

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1734
Author(s):  
Erick Franieck ◽  
Martin Fleischmann ◽  
Ole Hölck ◽  
Larysa Kutuzova ◽  
Andreas Kandelbauer
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Kinetic Parameters ◽  
Measurement Techniques ◽  
Process Conditions ◽  
Dielectric Analysis ◽  
High Glass Transition Temperature ◽  
General Process ◽  
Molding Compound

We report on the cure characterization, based on inline monitoring of the dielectric parameters, of a commercially available epoxy phenol resin molding compound with a high glass transition temperature (>195 °C), which is suitable for the direct packaging of electronic components. The resin was cured under isothermal temperatures close to general process conditions (165–185 °C). The material conversion was determined by measuring the ion viscosity. The change of the ion viscosity as a function of time and temperature was used to characterize the cross-linking behavior, following two separate approaches (model based and isoconversional). The determined kinetic parameters are in good agreement with those reported in the literature for EMCs and lead to accurate cure predictions under process-near conditions. Furthermore, the kinetic models based on dielectric analysis (DEA) were compared with standard offline differential scanning calorimetry (DSC) models, which were based on dynamic measurements. Many of the determined kinetic parameters had similar values for the different approaches. Major deviations were found for the parameters linked to the end of the reaction where vitrification phenomena occur under process-related conditions. The glass transition temperature of the inline molded parts was determined via thermomechanical analysis (TMA) to confirm the vitrification effect. The similarities and differences between the resulting kinetics models of the two different measurement techniques are presented and it is shown how dielectric analysis can be of high relevance for the characterization of the curing reaction under conditions close to series production.

Crystal structure and dielectric analysis of BiPr0.05FeO3 and BiPr0.10FeO3 multiferroic ceramics

2020 ◽  
Author(s):  
Muskaan Tuteja ◽  
Sujata Sanghi ◽  
Ashish Agarwal ◽  
Manisha Yadav ◽  
Tanvi Bhasin
Keyword(s):  
Crystal Structure ◽  
Dielectric Analysis

Dielectric analysis of photocrosslinked and post-sulfonated styrene-ethylene-butylene-styrene block copolymer based membranes

2020 ◽  
Vol 155 ◽  
pp. 104715
Author(s):  
R. Teruel-Juanes ◽  
B. Pascual-Jose ◽  
C. del Río ◽  
O. García ◽  
A. Ribes-Greus
Keyword(s):  
Block Copolymer ◽  
Dielectric Analysis

scholarly journals Molecular Dynamics of Functional Azide-Containing Acrylic Films

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 859 ◽  
Author(s):  
Marta Carsí ◽  
Maria Sanchis ◽  
Saul Vallejos ◽  
Félix García ◽  
José García
Keyword(s):  
General Structure ◽  
Glassy State ◽  
Interfacial Polarization ◽  
Dielectric Analysis ◽  
Azide Group ◽  
Low Frequencies ◽  
Polarization Effects ◽  
Dynamic Mobility ◽  
Models Comparison ◽  
Ohmic Conductivity

A report on the syntheses, thermal, mechanical and dielectric characterizations of two novel polymeric acrylic materials with azide groups in their pendant structures is presented. Having the same general structure, these polymers differ in length of oxyethylene units in the pendant chain [-CONH-CH2CH2-(O-CH2CH2)nN3], where n is 1 (poly(N-(2-(2-azidoethoxy)ethyl)methacrylamide), PAzMa1) or 2 (poly(N-2-(2-(2-azidoethoxy)ethoxy)ethyl)methacrylamide), PAzMa2), leading with changes in their dynamics. As the thermal decomposition of the azide group is observed above 100 °C, dielectric analysis was carried out in the temperature range of −120 °C to 100 °C. Dielectric spectra of both polymers exhibit in the glassy state two relaxations labelled in increasing order of temperature as γ- and β-processes, respectively. At high temperatures and low frequencies, the spectra are dominated by ohmic conductivity and interfacial polarization effects. Both, dipolar and conductive processes were characterized by using different models. Comparison of the dielectric activity obtained for PAzMa1 and PAzMa2 with those reported for crosslinked poly(2-ethoxyethylmethacrylate) (CEOEMA) was performed. The analysis of the length of oxyethylene pendant chain and the effect of the methacrylate or methacrylamide nature on the dynamic mobility was analysed.

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