Electrical properties of TiO/sub 2/ nanocomposites

Abstract

The incorporation of 38 nm titanium dioxide nanoparticles into an epoxy matrix to form a nanocomposite structure is described. The practical use of such materials has been evaluated through careful measurements of their electric strength made using recessed specimens as a function of particulate loading in comparison with an equivalent conventional resin formulated with micro-scale Ti02 ffler. The results would suggest that significant advantages accrue from the nano-formulated material in keeping with the known reduction in internal space charge accumulation earlier determined by pulse electroacoustic measurements. Furthermore, it is demonstrated that an optimum loading is indicated at about 10 % (by weight).Based on additional thermally stimulated current and electroluminescence data, some suggestions are advanced which explain the improved performance in terms of the mitigating effects of trapped entanglement on the Maxwell-Wagner effect.

Role of the interface in determining the dielectric properties of nanocomposites

“…It would appear that the Maxwell-Wagner polarization, well known to be associated with composites, is diminished in the case of the nanocomposites despite the substantial increase in the interfacial areas involved with the finely divided particulates. Such behavior has also been confirmed by static and dynamic electroluminescence studies [5] that support the view that the magnitude and distribution of the internal space charge is dramatically different in the two cases. The interpretation is clearly a major key to the engineering of useful nanodielectrics.…”

“…The second piece of evidence that is pertinent here is shown in Table 2, which shows the time constants of the decay for light emission [5] and for internal charge relaxation in the same TiO 2 nanocomposites. …”

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

“…In this way, the results of nanodielectric properties have little comparability and poor reproducibility, which has been confirmed by the reported data. Some groups reported that the nanoparticles can help to improve the short-term performance [13,[15][16], while others experiments observed the opposite results [17], indicating that the role of nanoparticles in matrix is still unclear in the short-term breakdown. However, the long-term performances, such as PD resistance and ageing resistance, are superior to the matrix.…”

Polyester and Polyesterimide Compounds with Nanofillers for Impregnating of Electrical Motors

“…The interactions between polymer matrix and nanoparticles alter polymer chemistry, i.e. chain mobility and degree of cure and generate new trap centers in the composite which brings about the significant change in electrical properties [1][2][3][4][5][6][7][8]. Where the size of the particle is close to that of the polymer chain length, the particles do not behave like foreign inclusions and space charge densities are small [6,9,10].…”

“…Nanoscale dispersion of fillers in the polymer reinforces their mechanical, thermal and dielectrical prop- * corresponding author; e-mail: gornicka@iel.wroc.pl erties compared to neat resins [5,7,8,[15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In the improvement of dielectrical properties both the enhanced scattering of the nanocomposite and mitigation of internal charge may play a role [8].…”