Characteristics of Gel Time and Dielectric Strength of Epoxy Composite According to the Mixing Ratio of Micro-Fillers

The dielectric strength and gel time of epoxy composites vary with the mixing ratio of epoxy resin, hardener, additives, filler, etc., and especially the gel time affects the productivity and economics of ultra-high-voltage (UHV) equipment. However, previous studies focused only on the dielectric strength of epoxy composites for the reliability of UHV equipment. Therefore, a study considering both the dielectric strength and gel time of the epoxy composite is required. In this paper, the characteristics of the gel time and dielectric strength of the epoxy micro-composites according to the mixing ratio of silica (SiO2) and alumina (Al2O3) micro-fillers without changing the mixing ratio of epoxy resin and hardener are analyzed. Experimental results show that the gel time decreased and the dielectric strength increased as the mixing ratio of the SiO2 micro-filler increased. Therefore, it is concluded that the gel time can be controlled by changing the mixing ratio of micro-fillers without changing the mixing ratio of the epoxy resin and hardener. In addition, experimental data can be used as basic data for economical production considering both the reliability and productivity of UHV power equipment.

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Electrical Conductivity and Micro Hardness of Synthetic and Natural Graphite Epoxy Composite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.447-448.614 ◽

2010 ◽

Vol 447-448 ◽

pp. 614-618 ◽

Cited By ~ 1

Author(s):

Hendra Suherman ◽

Jaafar Sahari ◽

Abu Bakar Sulong

Keyword(s):

Electrical Conductivity ◽

Epoxy Resin ◽

High Speed ◽

Epoxy Composite ◽

Filler Loading ◽

Epoxy Composites ◽

Micro Hardness ◽

Electron Microscopic ◽

Natural Graphite ◽

Weight Percentage

This study investigates the electrical conductivity and micro hardness of synthetic and natural graphite epoxy composite. Graphite used on this study is synthetic graphite (SG) and natural graphite (NG) with particle size 44m and 30m, respectively. Different graphite concentrations (50 ~ 80 wt.%) were added into the epoxy resin. The dispersion of graphite in epoxy resin was conducted by high speed mixer through mechanical shearing mechanism, its graphite epoxy suspension was poured into the mold and compression molding was conducted for fabrication of graphite epoxy composites. Electrical conductivity was measured by the four point probe. Microscopic analyses conducted on fracture surface use scanning electron microscopic. Results reveal that non conductive epoxy polymer becomes conductor as addition of graphite. Electrical conductivity of NG higher than SG at the same weight percentage (Wt. %) of conducting filler loading. The highest loading concentration, it exhibited values 12.6 S/cm and 7 S/cm at (80 Wt. %). Hardness property of epoxy composites of both type of graphite increase continuously and reached peak at 60 wt% for NG and 70 wt % for SG, while more addition decreased it.

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PEMANFAATAN SERBUK TEMPURUNG KELAPA PADA KOMPOSIT Al2O3-EPOXY

Dinamika Teknik Mesin ◽

10.29303/d.v3i2.75 ◽

2013 ◽

Vol 3 (2) ◽

Author(s):

Ahmad Syafruddin Zohri ◽

Nasmi Herlina Sari ◽

S. Sujita

Keyword(s):

Epoxy Resin ◽

Volume Fraction ◽

Epoxy Composite ◽

Method Comparison ◽

Wear Test ◽

Epoxy Composites ◽

Coconut Shell ◽

Alternative Material ◽

Coconut Shell Powder ◽

Shell Powder

The purpose of this research is utilization of coconut shell powder on Al2O3-Epoxy composite so it can be used as an alternative material of brake linings that are enviromentlly friendly. In this research, coconut shell powder is used as a filler on Al2O3-Epoxy composites that are made using hand lay up method. Comparison volume fraction of coconut shell powder and Al2O3 was varied amount 0:40, 10:30, 20:20, 30:10 and 40:0 (%). Adhesive was used is epoxy resin namely amount 60%. Test conducted is wear test. The results showed that utilization of coconut shell powder on Al2O3-Epoxy can be decrease the wear so it can be used as an alternative material of brake linings that are environmentally friendly

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Epoxy composites with increased operational characteristics, filled with dispersed mineral fillers

Proceedings of the Voronezh State University of Engineering Technologies ◽

10.20914/2310-1202-2018-3-330-335 ◽

2018 ◽

Vol 80 (3) ◽

pp. 330-335

Author(s):

A. S. Mostovoi ◽

A. S. Nurtazina ◽

Yu. A. Kadykova

Keyword(s):

Impact Strength ◽

Heat Resistance ◽

Epoxy Resin ◽

Oxygen Index ◽

Epoxy Composite ◽

Tensile Modulus ◽

Epoxy Composites ◽

Breaking Stress ◽

Mineral Fillers ◽

The Impact

The aim of this work is to increase the physicochemical, deformation and strength properties and to reduce the combustibility of composites on the base of epoxy resin by introducing a oligo(resorcinophenyl phosphate) with terminal phenyl groups Fyrolflex - modifier of polyfunctional action, and disperse mineral fillers – diorite and chromite. Result of the studies established that the optimum amount of modifier in the composition of the epoxy resin is 40 mass parts, which provides an increase in the operational properties of the composites: the breaking stress at bending increases by 2 times, the breaking stress at compression increases by 28%, the impact strength increases twice, while the modulus of elasticity and hardness of composites slightly decrease. The addition of modifier into the epoxy polymer provides an increase in heat resistance from 86 to 132–156 °C, also it improves the thermal stability of the composite, which manifests itself in a shift from the initial temperature to higher temperatures (from 200 to 230 °C), while it is noticed furthermore that yield of carbonized Structures was risen from 40 to 54%, providing less release of volatile pyrolysis products into the gas phase, which leads to the decrease in flammability of the epoxy composite and it can be shown in the reduction of its loss in mass while cauterizing in air from 78 to about 4.7% and an increase in the oxygen index from 19 to 28% by volume what transfers the material into class with low flammability. The rational content of diorite and chromite (100 parts by weight of chromite and 50 parts by mass of diorite) is chosen as a filler, which ensures an increase in physical and mechanical characteristics and a reduction in the cost of production: the breaking stress increases by 15–30% and the elastic modulus at bending increases 3.5–4.5 times, the breaking stress increases by 35%, and the tensile modulus by 50–240%, the hardness increases by 68–95%, while the impact strength remains at the level of the unfilled plasticized composite. In addition, it is proved that the addition of both diorite and chromite provides an increase in the thermal and heat resistance of epoxy composites, also lowers combustibility of the epoxy composite: the weight loss at ignition in air is reduced to 1.2–2.2% and the oxygen index rises from 28 to 30–35% by volume, thus the material does not support combustion in air and belongs to the class of hardly flammable. The study was carried out with the financial support of a grant for young scientists of the SSTU named after Gagarin Yu.A. (project SGTU-287).

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Functional Polymer Composite with Core-Shell Ceramic Filler: II. Rheology, Thermal, Mechanical, and Dielectric Properties

Polymers ◽

10.3390/polym13132161 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2161

Author(s):

Andrzej Rybak

Keyword(s):

Thermal Conductivity ◽

Epoxy Resin ◽

Epoxy Composite ◽

Linear Thermal Expansion ◽

Dielectric Strength ◽

Electrical Insulation ◽

Core Shell ◽

Dielectric Parameters ◽

Standard Material ◽

The Core

Epoxy resin composites filled with ceramic particles are commonly applied in electrification devices as an electrical insulation. In order to maintain proper functionality of such apparatuses it is crucial to optimize a broad range of properties, such as thermal, mechanical and dielectric parameters. In an earlier paper, a novel core-shell filler was developed in order to enhance the thermal conductivity in the epoxy composite used as electrical insulation. The new filler was made of a standard material, which was covered by a thin layer of high thermally conductive shell, namely, alumina coated by aluminum nitride. It was previously shown that the epoxy resin filled with the core-shell Al2O3@AlN particles showed a significant increase in thermal conductivity with a 63% relative increase. In this paper, a set of complementary measurements was performed and analyzed, namely, rheology, tensile strength, dynamic mechanical analysis, and dilatometry. Moreover, the dielectric permittivity and strength, and electrical resistivity were investigated in order to check if the electrical insulation properties were maintained. The obtained results were compared with the epoxy composite filled with the standard filler. The rheological behavior of the core-shell filled system showed that the processability will not be hindered. The mechanical properties of the composite based on core-shell filler are better than those of the reference system. The coefficient of linear thermal expansion is lower for epoxy filled with core-shell filler, which can lead to better adhesion to internal parts in the electrification devices. The dielectric strength was enhanced by 16% for the core-shell filled epoxy. The investigation clearly demonstrates that the epoxy composite filled with the core-shell particles is an appropriate material for application as electrical insulation with enhanced thermal conductivity.

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Dielectric spectroscopy and structural characterization of nano-filler-loaded epoxy resin

Journal of Advanced Dielectrics ◽

10.1142/s2010135x21500119 ◽

2021 ◽

pp. 2150011

Author(s):

S. G. Thakor ◽

V. A. Rana ◽

H. P. Vankar ◽

T. R. Pandit

Keyword(s):

Mechanical Properties ◽

Epoxy Resin ◽

Epoxy Composite ◽

Structural Information ◽

Epoxy Composites ◽

Neat Epoxy ◽

Frequency Range ◽

Additional Information ◽

Lcr Meter

This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [[Formula: see text](3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composites loaded with 1 wt.% of inorganic nano-fillers (SiO2, Al2O3, TiO2 and ZnO) were carried out using precision LCR meter, over the frequency range of 1 kHz–2 MHz at a constant temperature of 300.15 K. The structural information of nano-fillers, neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD. Moreover, hardness and shear strength (shear punch) were also determined in order to gain additional information about the mechanical properties of epoxy composite. Influence of inorganic nano-fillers on the dielectric properties, structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.

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Enhancement of Mechanical Properties of an Epoxy Composite Reinforced with Hibiscuss Sabdariffa VAR. Altissima Fiber Micro Cellulose

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1093.0782s419 ◽

2019 ◽

Vol 8 (2S4) ◽

pp. 477-480 ◽

Cited By ~ 1

Keyword(s):

Mechanical Properties ◽

Epoxy Resin ◽

Steam Explosion ◽

Epoxy Composite ◽

Epoxy Composites ◽

Reinforced Composites ◽

Fiber Loading ◽

Cellulosic Fibers ◽

Chemical Treatments ◽

Particle Form

The effects of micro cellulose reinforcement on the mechanical properties of epoxy composites were investigated. Micro cellulose were extracted from Hibiscuss sabdariffa fibers using the steam explosion technique and repeated chemical treatments. Reinforcing of epoxy resin with micro cellulosic fibers was done in particle form. Tensile, hardness and impact results revealed that mechanical properties of micro cellulose reinforced composites increases for 10%, 20% and 30% fiber loading and then decrease for 40% loading. Composite with 30% of micro cellulose enhanced the overall mechanical properties of composite, due to the enhanced fiber-matrix adhesion and micro cellulose reinforcement.

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Thermooxidative Degradation of Composites Based on Epoxy Resin and Metal Nanopowders

Materials Science Forum ◽

10.4028/www.scientific.net/msf.942.11 ◽

2019 ◽

Vol 942 ◽

pp. 11-20

Author(s):

Dmitry Lipchansky ◽

Olga B. Nazarenko

Keyword(s):

Thermal Stability ◽

Boric Acid ◽

Epoxy Resin ◽

Epoxy Composite ◽

Electrical Explosion ◽

Epoxy Composites ◽

Thermooxidative Degradation ◽

Air Atmosphere ◽

Metal Nanopowders ◽

Thermal Stability Of

The thermooxidative degradation behavior of the epoxy composites filled with metal nanopowders has been investigated by thermogravimetric analysis under nonisothermal conditions in air atmosphere. The mechanical characteristics of epoxy composites were also studied by three-point bending method. The comparison of two different types of metal nanopowder was made. Aluminum and copper nanopowders prepared by electrical explosion of wires were used as fillers separately as well as in combination with conventional fame-retardant boric acid. It was shown that aluminum nanopowder increased slightly thermal stability of the epoxy composites. On the contrary, the introduction of copper nanopowder in epoxy resin led to rapid degradation of the epoxy composite. The combination of metal nanopowders and boric acid improved thermal stability of the epoxy composites. The highest flexural properties showed the epoxy composite filled with copper nanopowder.

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Study on properties of nano-epoxy resin based-low temperature plasma

E3S Web of Conferences ◽

10.1051/e3sconf/202125102077 ◽

2021 ◽

Vol 251 ◽

pp. 02077

Author(s):

Xudan Wang

Keyword(s):

Low Temperature ◽

Epoxy Resin ◽

High Voltage ◽

Thermal Aging ◽

Superior Performance ◽

Power Equipment ◽

Low Temperature Plasma ◽

Temperature Plasma ◽

Before And After ◽

Positive Effect

In high-voltage power equipment, the traditional solid insulating dielectric is mainly polymer, epoxy resin (EP) is widely used because of its low price, superior performance, and easy processing. KH550 and low-temperature plasma fluorination in conjunction with KH550 modification in the paper is applied to improve nano-epoxy resin. EP samples with different treatment methods and different contents are prepared, and the insulation properties of EP materials before and after thermal aging are tested. It proves that the research results of the paper have a positive effect on the thermal aging characteristics of EP.

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