FIELD OF THE INVENTION
The present invention generally relates to enhancing AC breakdown voltage
(BDV) of conventional epoxy resin cast body through identification and
incorporation of suitable nano-structured dielectric filler material and fabrication
thereof the desired filler-modified epoxy resin composite body with improved
BDV. More particularly, the present invention relates to a nano-structural barium
aluminate modified epoxy resin composites to act as a superior electrical
insulation material for high voltage applications.
BACKGROUND OF THE INVENTION
The use of fillers in both thermoplastic and thermosetting polymers is known.
The usage of various fillers in the polymers enhances physical properties of the
composite body besides achieving a cost reduction. Conventionally, fillers are
made of commercial grade material/s with particle diameter of several microns.
In the recent years, fillers with nanostructures in the particulates have been
reported to be introduced in order to achieve composite materials both in
thermoplastic and thermosetting polymers with enhanced electrical, mechanical,
thermal and environmental properties.
Fillers could be active or inert. When the fillers are inert, they are primarily
extenders. However, with the addition of an active filler material or in the form of
active coating, fillers can be utilized as reinforcements in the composites.
The most widely used extender type of filler for plastics is calcium carbonate.
Calcium carbonate can also be coated with stearic acid and calcium stearate to
improve theological properties. Other organic materials, for example salts of

alkylolamines and long chain polyaminoamides (high molecular weight acids)
have also been used as coating materials.
Alumino-silicate materials for example, kaolin clay is another common material
that is used as extender in plastics, which is often treated with silane, polyester,
and metal hydroxide for surface modifications is also well known in this area.
Other aluminosilicate materials namely glass, asbestos group of materials, and
wollastonite etc have been reported to be used as reinforcements with and
without combinations of various surface modifying agents and have been used in
various industrial applications.
International Patent Publication Number WO2004034409 Al dated October 02,
2002 by J. Keith Nelson et al describes a dielectric body which comprises a
nanometric composite that includes a stoichiometric nano- particulate filler
embedded in a polymer or resin matrix. Filler particles are reduced in physical
size to dimension to the same order as the polymer chain length of the host
material and interact cooperatively thereby mitigating the associated Maxwell-
Wagner process and reducing interfacial polarization. The internal fields for the
new formulation are nearly a factor of 10 lower then for conventional (micro)
material. The large changes in the internal field of the composite permit
engineering of nanocomposite materials with enhanced electric strength and
improved voltage endurance properties.
European Patent Number EP2195813 Al dated June 16, 2010 by Martin Carlen et
al (ABB Research Ltd) describes an electrical insulation system with improved
electrical breakdown strength. The electrical insulation system comprises a
hardened polymer, incorporated with a conventional filler material and a selected
pre-treated filler material. The hardened polymer is selected from epoxy resin

systems, polyesters, polyamides, polybutylene terephthalate, polyurethanes and
polydicyclopentadiene, the conventional filler material is a known filler material
having an average grain size distribution within the range of 1 - 500 urn, being
present in a quantity within the range of 40 - 65 % by weight and the selected
pre- treated filler material is silica, quartz, or a silicate, or is a mixture of these
compounds, having an average grain size distribution within the range of 1-
500jam.
European Patent Number EP2532010 Al dated December 12, 2012 by Xavier
Kornmann et al (ABB Research Ltd) describes an electrical insulation system with
improved electrical breakdown strength. The said electrical insulation system
comprising a hardened polymer component having incorporated therein a
conventional filler material and a selected nano-scale sized filler material,
wherein (a) said hardened polymer component is selected from epoxy resin
compositions, polyesters, polyamides, polybutylene terephthalate, polyurethanes
and polydicyclopentadiene, and preferably is a hardened epoxy resin system; (b)
said conventional filler material is a known filler material having an average grain
size distribution within the range of 1-500 urn, being present in a quantity within
the range of 40-65% by weight, and (c) said selected nano-scale sized silica
powder is a pre-treated nano-scale sized filler material, having been produced by
a sol- gel process; wheifein said selected nano- scale sized silica powder is
present within the electrical insulation system in an amount of about 1-20% by
weight.
EP0500587 Al dated Sep 2, 1992 by Bradley Keith Coltrain et al (Eastman Kodak
Company) describes modified epoxy resins and composites which have silicon-
containing functional groups along the polymer backbone, and prepared by
reacting a polyether having non-terminal hydroxy groups with a modifying agent
which (i) reacts with hydroxy groups and (ii) which also contains trialkoxysilane

groups. The modified resins can be reacted with a silicon oxide precursor to form
an organic/inorganic composite. The composites are shown to have improved
properties at elevated temperatures.
European Patent Number EP1858969 A2 dated Nov 28, 2007 by Robert John
Keefe et al (Rensselaer Polytechnic Institute describes nanostructured dielectric
composite materials suitable for electrical insulation which includes a polymer
compounded with a substantially homogeneously distributed functionalized
nanoparticle filler. The nanocomposite material is produced by compounding the
polymer with the functionalized nanoparticle filler by imparting a shear force to a
mixture of the polymer and filler capable of preventing agglomeration of the filler
whereby the filler is substantially homogeneously distributed in the
nanocomposite material. The electrical insulation may be adapted for AC or DC
high voltage, and may also be adapted for low or medium voltage to prevent
formation of water tree structures.
EP2007830 Al dated December 31, 2008 (also published as US20090289234 &
WO2007119231A1) by J. Werner Blau et al (The Provost, Fellows And Scholars
Of The College Of The Holy And Undivided Trinity Of Queen Elizabeth Near
Dublin) describes a process for the preparation of modified nanoclay, which in
one embodiment comprises the steps of providing an organoclay, dispersing the
organoclay in a solvent or mixture of solvents and/or surfactant, providing
nanotubes or nanowires, dispersing the nanotubes or nanowires in a solvent or
mixture of solvents and/or surfactant, and mixing the organoclay suspension
with the nanotube and/or nanowire suspension. The organoclays modified with
nanowires or nanotubes provide nanoadditives, which enhanced thermal stability
and electrical conductivity properties. The nanoadditive may include an
inherently conducting polymer such as polyaniline. Also provided are polymer
composites including the nanoadditive.

EP2417171 Al dated Feb 15, 2012 by Linda Schadler et al (Rensselaer
Polytechnic Institute) describes an electric insulation material including modified
nanoparticles, a porous substrate and polymer matrix, wherein the modified
nanoparticles include a nanoparticle and a diblock copolymer covalently attached
to the nanoparticle, the diblock copolymer including a first block polymer of
molecular weight greater than 1000 and a glass transition temperature below
room temperature attached to the nanoparticle and a second block polymer of
molecular weight greater than 1000 covalently linked to the first block polymer,
wherein the second block polymer and the matrix both possess the same
chemical functionality. Other electrical insulation materials and methods of
making such electrical insulation materials are also disclosed.
United States Patent Number US8389603 dated March 5, 2013 by Tapas Yadav
et al describes the use of nanoscale powders as a component of novel
composites and devices. By incorporating powders having dimensions less than a
characteristic domain size into polymeric and other matrices, nanocomposites
with unique properties can be produced and methods for preparing
nanocomposites with thermal properties modified by powder size below 100
nanometers. Both low-loaded and highly-loaded nanocomposites were reported.
Nanoscale coated, un-coated, whisker type fillers are taught. Thermal
nanocomposite layers may also be prepared on substrates.
The present invention differs from the practices disclosed in the prior art. This
application does not use any conventional materials, like calcium carbonate, clay
or glass. Instead, this application use nano-structured amorphous barium
aluminate material which is functionalized with silane and thereby incorporated
into the commercial grade epoxy resin and hardener system targeting
enhancement of AC breakdown voltage (BDV) in the derived epoxy composite
material. This approach produces epoxy composite materials with enhanced BDV

by merely incorporating about 3 w% of the said filler material to that of the
blank epoxy system.
OBJECTS OF THE INVENTION
It is therefore the primary object of the invention to modify the conventional
epoxy resin system (commercial grade) by identifying and incorporating a
suitable dielectric filler material thereby fabricating the modified epoxy
composites that would have enhanced AC break down voltage (BDV), which
would act as a superior electrical insulation material as compare to conventional
epoxy resin cast body for high voltage applications.
Another objective is to define the said dielectric filler material, which is
nanostructured barium aluminate that has amorphous structure in the X-ray
powder diffraction (XRD) pattern and also has a tap density in the range of 0.2 -
0.3 g/cc and is synthesized by appropriately adopting in-house synthesis
technique.
Other objective is also to define the level/s of loading of nanostructured barium
aluminate filler material into the conventional epoxy system so as to maximize
the BDV in the modified epoxy resin composite body.
Further objective is to define the processing conditions and its process
parameters etc for incorporation of the filler material and thereby the fabrication
of the modified epoxy composite components with targeted level/s of BDV.
SUMMARY OF THE INVENTION
According to this invention, there is provided a process along with its parameters

for fabricating epoxy resin omposite body which is modified by a suitable
dielectric filler material, i.e., nanostructured amorphous barium aluminate having
tap density in the range of 0.2 - 0.3 g/cc for achieving enhanced AC break down
voltage (BDV) in the filler-modified composite body as compare to its
conventional epoxy resin body.
The incorporation and fabrication of the nano-structured amorphous barium
aluminate filler modified composites, comprise the following steps:
• Synthesis of nanostructured amorphous barium aluminate filler material
having tap density in the range of 0.2-0.3 g/cc by a known synthesis
process with defined properties and characteristics of the material (Table
1);
• preparing an "emulsion of nanostructured amorphous barium aluminate
filler" by mixing and treating nanostructured barium aluminate filler
material with liquid silane (functionalization agent) and a hardener
(carboxylic acid based anhydride in the commercial epoxy resin system)
in a 3D mixer using a pre-determined weight ratio in each of the
components;
• preparing another "mixed liquid" containing the materials, i.e.,
conventional epoxy resin (bisphenol-A Epoxy resin), flexibilizer
(polyglycol liquid) and accelerator (tertiary amine liquid) in a pre-defined
ratio thereby obtaining the "mixed liquid" using a high shear mixer;
• mixing the "emulsion of nanostructured amorphous barium aluminate
filler" and the "mixed liquid" together under vacuum with a pre-
determined ratio of the two components thereby obtaining a "filler-

modified epoxy resin emulsion";
• casting thus-obtained "filler-modified epoxy resin emulsion" into moulds
as per the dimension/shape of the components/specimens including de-
gassing to remove the air bubble in the composite body;
• heat treating the casted body in air in an oven in a temperature range of
80- 90°C preferably at 80°C for a period of 6 - 8 hours, which results in
a pre-cured filler modified resin body;
• heat treating of the pre-cured filler modified resin body in air in an oven
in the temperature range of 140° - 150°C preferably at 140°C for a
period of 6 - 8 hours, which results in a fully-cured "nanostructured
amorphous barium aluminate modified epoxy resin composite body";
and
• testing thus-derived "nanostructured amorphous barium aluminate
modified epoxy resin composite body" for AC breakdown voltage (BDV)
as per IEC standard
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1 - shows AC Breakdown voltage (BDV) profile of nanostructured
amorphous barium aluminate-modified epoxy composites according
to the invention as compared to blank conventional epoxy resin
body.
DETAILED DESCRIPTION OF THE INVENTION
The present invention refers to modification of conventional epoxy resin cast

body by identifying and incorporating a new dielectric material (as a filler), i.e.,
nanostructured amorphous barium aluminate and thereby fabricating an epoxy
composite body following pre-defined procedure and process parameters,
composite body of which has enhanced AC breakdown voltage (BDV), which
would serve as a superior electrical insulating material in high voltage
applications.
According to the first aspect of the invention, there is provided a nano-structural
barium aluminate modified epoxy resin composites to act as a superior electrical
insulation material for high voltage applications, comprising a filler material
consisting of nanostructured amorphous barium aluminate having properties and
values of:

wherein the nanostructured amorphous barium aluminate powder has a tap
density in the range of 0.2 - 0.3 g/cc, wherein a mixed liquid is prepared by
maintaining a weight ratio "200:20:2" for "epoxy: flexibiliser: accelerator"
respectively, wherein the emulsion and the mixed liquid is mixed by maintaining
a weight ratio of "1:1" to obtain a filler-modified epoxy emulsion, wherein the
filler-modified epoxy emulsion is casted under vacuum (0.5 - 5 mbar) in a
stainless steel mould and wherein the green epoxy composite body is pre-cured

in an oven in air in a temperature range of 80-90°C for a period of 6-8 hours to
obtain the pre-cured epoxy composite body, wherein the pre-cured epoxy
composite body is fully cured by heat treating in a temperature range of 140°-
150°C preferably at 140°C for a period of 6-8 hours to obtain the fully-cured
epoxy composite body.
According to the second aspect of the invention, there is provided a process for
incorporating nano-structured amorphous barium aluminate filler material for
fabricating filler-modified epoxy composites using variable loading of filler in the
epoxy resin system so as to enhance the BDV, which is disclosed in this
invention.
In a more particular embodiment of the present invention, the synthesis of nano-
structured amorphous barium aluminate dielectric material as a filler along with
its properties is defined in the Table 1 (below) and the same is synthesized by
adopting appropriately synthesis procedure in-house. As described, the new filler
dielectric material, i.e., nanostructured barium aluminate has unique properties,
which is amorphous in the XRD and having a tap density in the range of 0.2 - 0.3
g/cc and preferably the material with a tap density of about 0.25 g/cc were
chosen in this invention.
Table 1: Properties of Nano Structured Amorphous Barium Aluminate Filler



As per the invention, said nanostructured barium aluminate filler material having
the loading in the range of 1 - 4 weight% are first to be mixed with silane (y-
glycidoxypropyltrimethoxysilane) in the weight range of 1 - 2 % along with the
hardener liquid (which is chemically carboxylic acid anhydride based liquid) in the
conventional epoxy resin system using a 3D mixer or a planetary mixer after
which an emulsion results.
The resultant emulsion is then to be mixed with epoxy resin (bisphenol A epoxy
resin) along with flexibilizer (polyglycol based liquid) and accelerator (tertiary
amine based liquid) in pre-determined proportions using a vacuum mixer (with
de-gassing attachment) for a period of 30 - 60 minutes, maintaining the vacuum
level (0.5 - 5 mbar; lower is better) in which an emulsion-based filler-modified
epoxy resin system results.
The resultant emulsion-based filler-modified epoxy resin system is now to be
casted as per the shape/size of component and then to be de-gassed and further
to be heat treated in air by maintaining the set temperature range of 80 - 90°C
preferably at 80°C for a period of 6 - 8 hours, which results in pre-cured filler-
modified epoxy resin body.
The thus-derived pre-cured filler-modified epoxy body is to be heat treated in air
at a set temperature range of 140 - 150°C preferably at 140°C for a period of 6
- 8 hours and then to be cooled down to ambient temperature by which the fully
cured filler-modified epoxy composite body results.
The cured filler-modified epoxy composite bodies/articles are then removed from
the moulds in which a standard mould releasing agent was applied prior to

casting the filler-modified epoxy composite body.
The filler-modified epoxy composites are then tested for AC breakdown voltage
(BDV) performance using standard dimensions of the test samples as per IEC
norms.
The figure 1 represents BDV profile of the filler-modified epoxy composites as
compared to blank conventional epoxy system, both of which have been casted
under identical conditions.
The fully-cured epoxy composites of the invention shows AC breakdown voltage
(BDV) in the range of 54 - 62 kV depending on the load of nanostructured
barium aluminate filler material in the composite body as compared to blank
conventional epoxy with similar dimension of 51 kV, which is hence an
enhancement of BDV in the range of 5 - 25 % to that of its counter 'blank
conventional epoxy body'.
The derived epoxy composites according to the invention act as a superior
electrical insulation material in the field of high voltage insulation system for
producing numerous insulation components for indoor and outdoor use, various
bushings in GIS, potential transformers, current transformers, and also for base
insulators in the medium-voltage sector, in the production of insulators
associated with outdoor power switches, measuring transducers, lead-throughs,
and overvoltage protectors, in switchgear construction, in power switches, dry-
type transformers.
The invention would be more understood in terms of taking various examples,
which are explained in the following:

EXAMPLE 1:
As per this example, non-structured amorphous barium aluminate dielectric
material which is used as a filler was synthesized in-house by adopting
appropriately as a synthesis process using LPG-fired Spray Pyrolysis System
(LPG=liquid petroleum gas).
As described this filler material has its typical properties which is amorphous in
the XRD and has a tap density in the range of 0.2 - 0.3 g/cc and the material
with a tap density of 0.249g/cc was used in this example. The filler material was
oven dried in air at a set temperature of 300°C for a period of 2 hours before
using it; this procedure is to let out the filler material from the entrapped
moisture.
200 parts by weight of liquid hardener (carboxylic acid anhydride based liquid)
(200 g) is first mixed with liquid silane (y-glycidoxypropyltrimethoxysilane)
(4.22g). To this solution, nanostructured barium aluminate filler 1 wt%
equivalent to 4.22 g is then mixed using a high speed mechanical stirrer for a
period of 30 minutes and then ultrasonicated for a period of 15 minutes so that
the filler powders are dispersed into the solution and an emulsion is resulted,
which is termed as "Emulsion A".
In another container (glass/plastic or stainless steel), epoxy resin (bisphenol A)
(200g), flexibiliser (polyglycol based liquid) (20g) and accelerator (tertiary amine
based liquid) (2g) were taken and mixed using a mechanical stirrer for a period
of 20 minutes to get a uniformly mixed liquid resulted, which is termed as "Liquid
B".
"Liquid B" is then mixed with the "Emulsion A" for a period of 45 minutes using a

high shear mechanical mixer. After this mixing, the whole mix is transferred to a
vacuum casting system wherein it is degassed.
Stainless steel moulds with dimensions of (150x150x3 mm) are first smeared
with standard mould releasing agent and the degassed mix is then vacuum
casted to these moulds by maintaining a thickness of 3 mm.
These liquid filled moulds are then transferred to an oven and heat treated in air
at 80°C for a period of 6 hours which resulted the pre-cured "nanostructured
barium aluminate modified epoxy composites".
The said pre-cured composites is then heat treated at 140°C for a period of
another 6 hours and then cooled down at ambient temperature by which the
fully cured "nanostructured barium aluminate modified epoxy composites" with
dimensions of 150x150x3 mm resulted which were released from the moulds and
tested for AC breakdown voltage (BDV) following IEC norms.
For comparison, conventional epoxy resin body with dimensions of 150x150x3
mm was also casted without using any filler in the epoxy system and subjected
to BDV tests following the same IEC norms.
The derived composite showed a breakdown voltage of 54 kV which is about
5.8% higher than the blank conventional epoxy body.
Example 2:
In this example, the procedure and all the experimental conditions were followed
exactly the same that is described in the example 1, except that the filler load,
i.e., the load of nanostructured amorphous barium aluminate powder was 2 wt%

instead of 1 wt% in the example 1.
The derived composite showed a breakdown voltage of 57 kV which is about
11.7% higher than the conventional epoxy body.
Example 3:
In this example, the procedure and all the experimental conditions were followed
exactly that is described in the example 1, except that the filler load, i.e., load of
nanostructured amorphous barium aluminate powder was 3 wt% instead of 1
wt% in the example 1.
The derived composite showed a breakdown voltage of 62 kV, which is about
21.5% higher than the conventional epoxy body.
Example 4:
In this example, the procedure and all the experimental conditions were followed
exactly that is described in the example 1, except that the filler load, i.e., the
load of nanostructured barium aluminate powder was 4 wt% instead of 1 wt% in
the example 1.
The derived composite showed a breakdown voltage of 55 kV which is 7.8%
higher than the conventional epoxy body.

WE CLAIM
1. A nano-structured barium aluminate modified epoxy resin composites to
act as a superior electrical insulation material for high voltage applications,
comprising a filler material consisting of nanostructured amorphous
barium aluminate having properties and values of:

wherein the nanostructured amorphous barium aluminate powder has a
tap density in the range of 0.2 - 0.3 g/cc,
wherein a "mixed liquid" is prepared by maintaining a weight ratio
"200:20:2" for "epoxy: flexibiliser: accelerator" respectively,
wherein the "emulsion" and the "mixed liquid" is mixed by maintaining a
weight ratio of "1:1" to obtain a filler-modified epoxy emulsion,
wherein the filler-modified epoxy emulsion is casted under vacuum (0.5 -
5 mbar) in a stainless steel mould and wherein the green epoxy composite
body is pre-cured in an oven in air in a temperature range of 80-90°C for
a period of 6-8 hours to obtain the pre-cured epoxy composite body,
wherein the pre-cured epoxy composite body is fully cured by heat

treating in a temperature range of 140°-150°C preferably at 140°C for a
period of 6-8 hours to obtain the fully-cured epoxy composite body.
2. A process for manufacturing filler-modified epoxy resin composites with
enhanced AC breakdown voltage (BDV) to act as a superior electrical
insulation material for high voltage application, comprising the steps of:-
- synthesizing a of nanostructured amorphous barium aluminate filler
material having tap density in the range of 0.2-0.3 g/cc by a known
synthesis process with defined properties and characteristics of the
material (Table 1);
- preparing an "emulsion of nanostructure amorphous barium aluminate
filler" by mixing and treating nanostructured barium aluminate filler
material with liquid silane (functionalization agent) and a hardener
(carboxylic acid based anhydride in the commercial epoxy resin
system) in a 3D mixer using a pre-determined weight ratio in each of
the components;
- preparing another "mixed liquid" containing the materials, i.e.,
conventional epoxy resin (bisphenol-a Epoxy resin), flexibilizer
(polyglycol liquid) and accelerator (tertiary amine liquid) in a pre-
defined ratio thereby obtaining the "mixed liquid" using a high shear
mixer;
- mixing the "emulsion of nanostructured amorphous barium aluminate
filler" and the "mixed liquid" together under vacuum with a pre-
determined ratio of the two components thereby obtaining a "filler-
modified epoxy resin emulsion";

- casting thus-obtained "filler-modified epoxy resin emulsion" into
moulds as per the dimension/shape of the components/specimens
including de-gassing to remove the air bubble in the composite body;
- heat treating the casted body in air in an oven in a temperature range
of 80- 90°C preferably at 80°C for a period of 6 - 8 hours, which
results in a pre-cured filler modified resin body;
- heat treating of the pre-cured filler modified resin body in air in an
oven in the temperature range of 140° - 150°C preferably at 140°C for
a period of 6 - 8 hours, which results in a fully-cured "nanostructured
amorphous barium aluminate modified epoxy resin composite body";
and
- testing thus-derived "nanostructured amorphous barium aluminate
modified epoxy resin composite body" for AC breakdown voltage (BDV)
as per IEC standard

3. The process as claimed in claim 2, wherein the nanostructured amorphous
barium aluminate is converted into an emulsion by mixing and milling,
maintaining a weight ratio of "4.22 - 16.88 : 4.22 - 16.88 : 200" thereof
for "barium aluminate : silane : hardener" depending on the load of
barium aluminate filler to be used in the epoxy composites.
4. The 'mixed liquid' as claimed in the claim 1, is prepared by maintaining a
weight ratio thereof "200 : 20 : 2" for "epoxy : flexibiliser: accelerator.
5. The "mixed liquid" as claimed in claim 1, is to be mixed with "emulsion of
nanostructured barium aluminate" by maintaining a weight ratio thereof
"1: 1" in order to obtain the so-called "filler-modified epoxy emulsion.

6. The "filler-modified epoxy emulsion" as claimed in claim 1, is to be casted
under vacuum (0.5 - 5 mbar, lower level is better) in a stainless steel
mould or suitable mould depending on the dimension of the component
for obtaining "green epoxy composite body" which is then to be pre-cured
in an oven in air in the temperature range of 80-90°C preferably at 80°C
for a period of 6-8 hours in order to obtain "pre-cured epoxy composite
body.
7. The "pre-cured epoxy composite body" as claimed in claim 1, is to be fully
cured by heat treating in the temperature range of 140°-150°C preferably
at 140°C for a period of 6 - 8 hours in order to obtain "fully-cured epoxy
composite body" or simply epoxy composites.
8. The fully-cured epoxy composites as claimed in claim 1, shows the
enhancement of AC breakdown voltage (BDV) in the range of 5 - 25 % to
that of its counter 'blank conventional epoxy body'.
9. Usage of the derived 'epoxy composites' according to any one of the
claims 1-8, are as a superior electrical insulation material in the field of
high voltage insulation system for producing numerous insulation
components for indoor and outdoor use, various bushings in GIS, potential
transformers, current transformers, and also for base insulators in the
medium-voltage sector, in the production of insulators associated with
outdoor power switches, measuring transducers, lead-throughs, and
overvoltage protectors, in switchgear construction, in power switches, dry-
type transformers etc.

ABSTRACT

The invention describes the enhancement of AC breakdown voltage (BDV) of
epoxy resin cast body using nanostructured barium aluminate as a dielectric filler
material, for high voltage electrical applications with superior insulation
properties. Nanostructured barium aluminate having amorphous structure in the
x-ray diffraction (XRD) with a tap density in the range of 0.2 - 0.3 g/cc, is
functionalized with silane by using liquid hardener as a media in the epoxy resin
system, which is then treated with a conventional epoxy resin, accelerator,
flexibilizer in a pre-defined ratio followed by heat treatment and curing in order
to derive the barium aluminate filler-modified epoxy composite body. Thus
modified epoxy composite body shows enhancement of AC breakdown voltage in
the range of 5 - 25% merely by loading the barium aluminate filler in the range
of 1 - 3 wt% in the conventional epoxy resin matrix. The modified resin
composite body is used for fabricating various components in the area of high
voltage electrical insulation applications.