Dielectric relaxation in polymer solids Part 2: Application of the new model to polyurethane systems

Schlosser, E.; Schönhals, Andreas

doi:10.1007/bf01410351

Cited by 39 publications

(15 citation statements)

References 6 publications

(7 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This frequency range is related to the mean relaxation time of the process and characterizes the molecular mobility (at the temperature of the investigation). 28 An increase in the foam in the composite leads to lower interactions with the polymer matrix, thereby slightly increasing the frequency of occurrence of the drop in the dielectric constant. The width and asymmetry of the relaxation function in polymer composites usually deviate from the values of the Debye function.…”

Section: Resultsmentioning

confidence: 99%

Dielectric studies of conductive carbon black reinforced microcellular ethylene–propylene–diene monomer vulcanizates

Mahapatra

Sridhar

Tripathy

2007

J of Applied Polymer Sci

View full text Add to dashboard Cite

The alternating-current and electrical conductivity of conductive, carbon black reinforced, microcellular ethylene-propylene-diene monomer vulcanizates was measured in the frequency range of 100 Hz to 1 MHz. The effects of variations in the filler and blowing-agent loadings on the dielectric constant and percolation behavior were studied. The phenomenon of percolation was examined on the basis of measured changes in the electrical conductivity and morphology of composites with different concentrations of the filler. Scanning electron microphotographs showed the agglomeration of the filler above these concentrations and the formation of a continuous network structure. The experimental results were not in agreement with the predictions of the statistical percolation theory; this deviation was explained in light of the formation of an interphase or mesostructure in the composites. The variation of the dielectric constant with the filler and blowingagent loadings was explained on the basis of polarization of the filler in the polymer matrix. Additionally, the use of dielectric mixture laws in describing the dielectric constants of both solid and microcellular composites was investigated.

show abstract

Section: Resultsmentioning

confidence: 99%

Dielectric studies of conductive carbon black reinforced microcellular ethylene–propylene–diene monomer vulcanizates

Mahapatra

Sridhar

Tripathy

2007

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…In that case, the H–N equations can be reduced to where n is the shape parameter. n is related to the shape parameters of the H–N model as follows: The following relation can be derived from eqs 9 and 10: The proposed simple model is similar to, but more specific than, the Schonhals–Schlosser (S–S) model 17, 18. In this model, where m and n are shape parameters and ω 0 is the angular frequency at which ε″ is maximum.…”

Section: Resultsmentioning

confidence: 99%

Dielectric analysis of a crosslinking epoxy resin at a high microwave frequency

Zong

Zhou

Sun

et al. 2004

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

The dielectric properties of a curing epoxy/amine system have been studied from 25 to 120°C at 2.45 GHz. The epoxy resins at different extents of curing exhibit a ␥ relaxation, which can be described by the Arrhenius rate law. The relaxation is attributed to the motions of the dipolar groups associated with the crosslinking system. A simple model is proposed to represent the temperature dependence of the dielectric properties. A complete description of the evolution of the parameters during the polymerization has been obtained. The nature of the information yielded by dielectrometry on the dynamics of the system is discussed.

show abstract

“…where ω 0 is the angular frequency at which ε″ is maximum. The analysis of the loss peak shape may equivalently be performed by means of the Havriliak-Negami adjustment parameters α H − N and β H − N , as m S − S = α H − N and n S − S = α H − N .β H − N [7]. However, in this study, power laws on both sides of the peak better fitted experimental data than the Havriliak-Negami equation, in particular for the points farther from the peak maximum.…”

Section: Shape Of the α-Relaxation Loss Peakmentioning

confidence: 99%

“…Broadband Dielectric Spectroscopy proved to be a particularly adequate tool for that purpose. Regarding three-dimensional polymer networks, multiple studies involving a variety of polymers [7][8][9][10] including silicone networks [11,12] led to the general conclusion that an increasing degree of crosslinking results in a slowing-down of the α-relaxation dynamics, as well as a more pronounced deviation from Arrhenius behavior: crosslinked polymers tend to be more fragile than linear ones with the same backbone. In such studies, the degree of crosslinking is generally controlled chemically (i.e.…”

Section: Introductionmentioning

confidence: 99%

Dynamic glass transition of filled polysiloxane upon electron irradiation

Roggero

Dantras

Paulmier

et al. 2017

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

a b s t r a c tThe influence of radiation-induced crosslinking on the molecular mobility of a filled silicone elastomer near the glass transition (α-relaxation) was analyzed using broadband dielectric spectroscopy. Samples of the isolated polysiloxane matrix (neat) were also studied so as to assess the filler influence on the evolution of the αrelaxation. A slowing-down of the segmental dynamics was observed with increasing ionizing dose. It was ascribed to the relaxing dipoles losing degrees of freedom as a result of network stiffening. An enhancement of intermolecular coupling, associated with the cooperativity of the α-relaxation, was deduced from the dielectric analysis. Similar observations were made in the past with chemically crosslinked polysiloxanes. This study evidenced that even though the crosslinks formed upon chemical crosslinking (mainly Si\ \CH 2 \ \CH 2 \ \Si) differ in nature from those formed upon irradiation (mainly SiO 3 and SiO 4 ), they affect the dynamic glass transition in a very similar way. The filler influence on the dynamic glass transition was also studied upon irradiation. One of the main outcomes of this study is the fading of the filler-related effect in the most irradiated samples: both the shape and dynamics of the α-relaxation were identical in the most highly irradiated neat and filled samples.

show abstract

Dielectric relaxation in polymer solids Part 2: Application of the new model to polyurethane systems

Cited by 39 publications

References 6 publications

Dielectric studies of conductive carbon black reinforced microcellular ethylene–propylene–diene monomer vulcanizates

Dielectric studies of conductive carbon black reinforced microcellular ethylene–propylene–diene monomer vulcanizates

Dielectric analysis of a crosslinking epoxy resin at a high microwave frequency

Dynamic glass transition of filled polysiloxane upon electron irradiation

Contact Info

Product

Resources

About