Polyurethane latex/water dispersible boehmite alumina nanocomposites: Thermal, mechanical and dielectrical properties

Gatos, Konstantinos G.; Alcázar, J.G. Martínez; Psarras, G. C.; Thomann, Ralf; Karger‐Kocsis, J.

doi:10.1016/j.compscitech.2006.07.025

Cited by 86 publications

(24 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Enhanced values of ("&), especially at low frequencies, can be attributed to increased conductivity, and/or interfacial polarization, and/or electrode polarization. Electrode polarization is related to the build up of space charges at the specimen-electrode interfaces and is characterized by very high values of both real and imaginary part of dielectric permittivity [21][22][23]. Examined samples were tested under identical experimental conditions, having similar geometrical characteristics and composition.…”

Section: Resultsmentioning

confidence: 99%

“…Although, all three formalisms can be employed on the description and analysis of the occurring electrical effects, a certain formalism can be proved more effective in extracting information regarding the occurring physical mechanisms under specific con- ditions. In the present study, experimental data were firstly expressed via the real and imaginary part of dielectric permittivity and then transformed into electric modulus formalism [21][22][23]. Figure 6a depicts the variation of real part of dielectric permittivity ("&) with frequency for all types of the produced composites at constant temperature (30°C) and nanofiller content (1 wt%).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Functionalized graphene – poly(vinyl alcohol) nanocomposites: Physical and dielectric properties

Tantis¹,

Psarras

Tasis³

2012

Express Polym. Lett.

165

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Functionalized graphene – poly(vinyl alcohol) nanocomposites: Physical and dielectric properties

Tantis¹,

Psarras

Tasis³

2012

Express Polym. Lett.

165

View full text Add to dashboard Cite

“…The repeat unit of PUR chain is composed by stiff, rigid blocks and soft rubbery blocks. In that sense IP arises from ionic polarization occurring at the interface of hard and soft regions as well as from variations of the morphology between amorphous and crystalline segments [16][17][18]. The dielectric spectra of the PUR/NR blend include contributions from both polymers, and thus in the low temperature range ( Figure 4) the fast processes of local motions of small parts (β and γ-modes) of the PUR chain as well as the α-mode of NR are present.…”

Section: Resultsmentioning

confidence: 99%

Relaxation phenomena in rubber/layered silicate nanocomposites

Psarras

Gatos²,

Karahaliou³

et al. 2007

Express Polym. Lett.

Self Cite

View full text Add to dashboard Cite

The impact of nanomaterials and/or nanostructured materials is well known and well appreciated [1][2][3][4], mostly due to their potential applications based on their thermo-mechanical performance, flame resistance, electrical properties etc. Polymer matrix nanocomposites can be prepared by dispersing a small amount of nanometer size filler within the host medium. Rubber/Layered Silicate (LS) nanocomposites are increasingly attracting scientific and technological attention, because of the high reinforcing efficiency of the LS, even at very low loading. Polymer matrix/LS nanocomposites exhibit three different configurations: (a) microphase separated composites, where polymer matrix and layered silicates remain immiscible, (b) intercalated structures, where polymer molecules are inserted between the silicate layers, and (c) exfoliated structures, where individual silicate layers are dispersed in the polymer matrix. Polymer matrix nanocomposites are expected to be useful in replacing conventional insulating materials providing tailored performance, by simply controlling the type and the concentration of nanoinclusions [5][6][7][8]. 'Nanodielectrics' is a rather new term associating dielectrics with nanotechnology [9]. Nanoinclusions could be able to serve as inherent nanocapacitors. Charging and discharging 837 * Corresponding author, e-mail: G.C.Psarras@upatras.gr © BME-PT and GTE Abstract. Broadband Dielectric Spectroscopy (BDS) is employed in order to investigate relaxation phenomena occurring in natural rubber (NR), polyurethane rubber (PUR) and PUR/NR blend based nanocomposites, reinforced by 10 parts per hundred (phr) Layered Silicates (LS). Nanocomposites and matrices were examined under identical conditions in a wide frequency (10 -1 to 10 6 Hz) and temperature (-100 to 50°C) range. Experimental data are analyzed in terms of electric modulus formalism. The recorded relaxation phenomena include contributions from both the polymer matrices and the nanofiller. Natural rubber is a non-polar material and its performance is only slightly affected by the presence of layered silicates. Polyurethane rubber exhibits four distinct relaxation processes attributed, with ascending relaxation rate, to Interfacial Polarization (IP), glass/rubber transition (α-mode), local motions of polar side groups and small segments of the polymer chain (β, γ-mode). The same processes have been detected in all systems containing PUR. IP is present in all nanocomposites being the slowest recorded process. Finally, pronounced interfacial relaxation phenomena, occurring in the PUR+10 phr LS spectra, are attributed to nanoscale effects of intercalation and exfoliation.Keywords : polymer composites, nanocomposites, dielectric spectroscopy, relaxations, rubber eXPRESS Polymer Letters Vol.1, No.12 (2007) [837][838][839][840][841][842][843][844][845] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2007.116 under control the embedded in a matrix nanocapacitors, defines an energy storing procedure at the nanoscal...

show abstract

“…Pure PU systems have been examined both mechanically [16] and dielectrically [37][38][39]. The results of these two methods are in good agreement, revealing three relaxation mechanisms for PU, namely α, β and γ modes recorded with increasing temperature at constant frequency.…”

Section: Introductionmentioning

confidence: 50%

“…The overlapping of the two relaxations is more pronounced in the case of POM/PU/LS (MB) system. In the middle area of the dielectric spectra of figures 3a,b and at the low frequency region, a weak relaxation peak is recorded, assigned to β-mode of PU [36] and attributed to local motions of polar side groups of the PU polymer chain imposed by the electric field [36,37]. The intensity of this mechanism is relatively weak and not well imprinted in the dielectric spectra.…”

Section: Dielectricsmentioning

confidence: 99%

Dielectric relaxation mechanisms in polyoxymethylene/polyurethane/layered silicates hybrid nanocomposites

Tomara

Karahaliou

Psarras

et al. 2017

European Polymer Journal

Self Cite

View full text Add to dashboard Cite

Polyoxymethylene/Polyurethane/Layered Silicates (POM/PU/LS) ternary hybrid nanocomposites were prepared by two methods: (a) direct melt compounding (DM) and (b) melt compounding using a latex-mediated masterbatch (MB) technique. The morphology of the produced specimens and the quality of the dispersion of LS (synthetic sodium fluorohectorite) were examined via Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Broadband dielectric spectroscopy (BDS) was employed in order to study the dielectric response of the two systems in a wide frequency and temperature range. Rich dielectric spectra are recorded, since dielectric relaxation mechanisms originate from POM matrix, PU latex as well as from interfacial phenomena between LS and the polymer matrix. Six different mechanisms were observed in the spectra of the examined

show abstract

Polyurethane latex/water dispersible boehmite alumina nanocomposites: Thermal, mechanical and dielectrical properties

Cited by 86 publications

References 53 publications

Functionalized graphene – poly(vinyl alcohol) nanocomposites: Physical and dielectric properties

Functionalized graphene – poly(vinyl alcohol) nanocomposites: Physical and dielectric properties

Relaxation phenomena in rubber/layered silicate nanocomposites

Dielectric relaxation mechanisms in polyoxymethylene/polyurethane/layered silicates hybrid nanocomposites

Contact Info

Product

Resources

About