Preparation and properties of epoxy-organically modified layered silicate nanocomposites

Imai, T.; Hirano, Yoshihiko; Hirai, H.; Shoichi, Kojima; Shimizu, Toshio

doi:10.1109/elinsl.2002.995955

Cited by 54 publications

(45 citation statements)

References 7 publications

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“…Regarding the large increase in the storage modulus in a rubbery state region based on these results, it can be definitely considered that the homogeneous dispersion and the excellent interfacial coupling force in a mixture state of the micro and nano particles limits the mobility of the epoxy molecules [10][11][12][13]. This can be detected in the cross-linking density.…”

Section: The Dmamentioning

confidence: 99%

The Properties of DSC and DMA for Epoxy Nano-and-Micro Mixture Composites

Lee¹,

Park²

2010

Transactions on Electrical and Electronic Materials

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As noted in Table 1, the epoxy resins that are not made with nano-fillers are referred to as conventional epoxy resins and the composites in which the conventional micro scaled epoxies are made with nano-fillers are referred to as epoxy nano-and-micro mixture composites (ENMCs). Three different ENMCs were fabricated with the composition ratios shown in Table 1.As this table shows, all of the epoxies were made with the same basic ratios of resin, hardener, and microparticles. The three different ENMCs are differentiated by nano SiO 2 concentrations of 0.5, 1, and 5 phr. In addition, this study looked at the effects of the silane processing (silane coupling agent: KBE_903_2.5 phr) for the micro composites. Keywords:Epoxy nano-and-micro mixture composites, Microcomposites, Cross-linking density, Differential scanning calorimeter, Dynamic mechanical analyser This study investigates the thermal and mechanical properties of insulation elements through the mixing of epoxy based micro and nano particles. Regarding their thermal properties, differential scanning calorimeter and dynamic mechanical analyser were used to calculate the cross-linking densities for various types of insulation elements. The mechanical properties of the bending strength, the shape and scale parameters, were obtained using the Weibull plot. This study obtained the best results in the scale parameters, at 0.5 phr, for the bending strength of the epoxy nanoand-micro mixture composites.

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Section: The Dmamentioning

confidence: 99%

The Properties of DSC and DMA for Epoxy Nano-and-Micro Mixture Composites

Lee¹,

Park²

2010

Transactions on Electrical and Electronic Materials

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“…Moreover, for the former the peak amplitude is much larger. Previous investigations (6) showed that a 6%wt EVA-Somasif microcomposite (obtained with a not compatibilised clay) does not Fig. 1.…”

Section: Dielectric Spectroscopymentioning

confidence: 99%

Polarization Processes of Nanocomposite Silicate-EVA and PP Materials

Montanari

Palmieri

Testa³

et al. 2006

IEEJ Trans. FM

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Recent works indicate that polypropylene (PP) and ethylene-vinylacetate (EVA) filled by nanosilicates may present low content of space charge and high electric strength. It has been proved that the dispersion of an inorganic phase in the polymeric matrix may improve voltage endurance, dielectric strength, thermal stability and mechanical properties in relation to particle size and arrangement on nanometric scale. Two polymeric materials, widely employed as electrical insulation for apparatus involved in energy transport, that is, ethylene vinylacetate (EVA) and isotactic polypropylene (PP) are examined. The nanofiller consists of an organophilic layered silicate (MEE), the purified MEE will be named MEE-w.Dielectric spectroscopy in time and frequency domain constitutes a useful tool for electrical insulation evaluation and diagnosis, and it can contribute to the understanding of electrical behaviour of complex solid polymer systems. In this paper, the results of dielectric spectroscopy analysis in time and frequency domain, for purified and unpurified filler nanocomposites, in a wide temperature range, are presented.Frequency-domain dielectric measurements were performed in order to appreciate the relaxation processes taking place at lower temperatures (-20 to 20 °C) over the 10 2 -10 6 Hz frequency range.The charging-discharging current measurements, through Fourier time to frequency data transformation, gave information about the slowest polarisation processes, that are usually hidden by the conduction current contribution. Space charge measurement data are also considered in order to understand the effect of nanostructuration and purification on charge carriers. While the relaxation process of EVA, α process, associated with glass transition of the material amorphous phase, results unchanged from base to nanostructured material (i.e., the nanofiller particles do not affect the chain mobility of the polymer), nanocomposites EVA and PP have shown the rise of a new process at higher temperatures respect to the typical host material processes, as well as a different distribution of relaxation processes. In Fig. 1, that displays the imaginary permittivity of EVA+MEE-w nanocomposite, the loss peaks, due to the α and α' process, can be clearly seen. The α' process can be ascribed to the interaction between the polymer matrix and MEE nanolayers.The temperature location of the process, which approaches the melting region of EVA, and its absence in the pure polymer let us argue that the α' relaxation process can be ascribed to a charge polarization of the Maxwell-Wagner-Sillars type, which is due likely to charge trapping at the interfaces between the nanofiller particles and the polymer. All the presented relaxation processes are thermally-activated and their activation energies, reported in Table 1, were estimated reporting the loss peak frequency and temperature of the isothermal measurements in the Arrhenius plot.The EVA nanocomposite obtained by an unpurified filler has shown a huge increment of real and imaginary...

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“…Nanodielectrics have attracted a great attention since the first experimental data were reported publicly in 2002 [10][11]. The current research is concentrated on the short-term breakdown and the long-term failure of epoxy and other polymer matrix with inorganic nanoparticles added.…”

Section: Introductionmentioning

confidence: 99%

Short-term breakdown and long-term failure in nanodielectrics: a review

Yin

Chen

et al. 2010

IEEE Trans. Dielect. Electr. Insul.

291

172

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Nanodielectrics, which are concentrated in polymer matrix incorporating nanofillers, have received considerable attention due to their potential benefits as dielectrics. In this paper, short-term breakdown and long-term failure properties of nanodielectrics have been reviewed. The characteristics of polymer matrix, types of nanoparticle and its content, and waveforms of the applied voltage are fully evaluated. In order to effectively comment on the published experimental data, a ratio k has been proposed to compare the electric properties of the nanodielectrics with the matrix and assess the effect for nanoparticles doping. There is evidence that the short-term breakdown properties of nanodielectrics show a strong dependence on the applied voltage waveforms. The polarity and the cohesive energy density (CED) of polymer matrix have a dramatic influence on the properties of nanodielectrics. Nanoparticle doped composites show a positive effect on the long-term failure properties, such as ageing resistance and partial discharge (PD) properties of nanocomposites are superior than microcomposites and the matrix. The larger the dielectric constant and CED of the matrix become, the more significant improvements in long-term performance appear. Based on the reported experimental results, we also present our understandings and propose some suggestions for further work.

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Preparation and properties of epoxy-organically modified layered silicate nanocomposites

Cited by 54 publications

References 7 publications

The Properties of DSC and DMA for Epoxy Nano-and-Micro Mixture Composites

The Properties of DSC and DMA for Epoxy Nano-and-Micro Mixture Composites

Polarization Processes of Nanocomposite Silicate-EVA and PP Materials

Short-term breakdown and long-term failure in nanodielectrics: a review

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