134 / 2018-08-25 00:25:32

The Impact of Coal Fly Ash Micro Filler on Dielectric Property of Silicon Rubber

Silicon Rubber, Coal Fly Ash

The Impact of Coal Fly Ash Micro Filler on Dielectric Property of Silicon Rubber

Tajuddin Waris1,2, Yoshinobu Murakami1, Tomohiro Kawashima1, Naohiro Hozumi1
1Departement of Electrical and Electronic InformationToyohashi University of technology
Tempaku Cho, Hibarigauka Japan
2Departement of Electrical Engineering, Hasanuddin University
Makassar Km.11, South Sulawesi Indonesia



Abstract


A silicone rubber (SiR) has been commonly used as an insulating material for an outdoor insulation due to its excellent properties like the tracking resistance, the erosion resistance, the hydrophobicity, the UV stability, the weight stability and the lower cost . To improve the properties and reduce the cost of the polymer insulation, the application of micro or nano filler is required. The SiR with an organic filler, i.e. SiR/Filler composite, has also been developed to optimize its function for a specific application such as high polluted area application, high mechanical and fire retardant requirement. For example, the incorporation of the ATH to SiR lead to improvement of the dry band arcing resistance and of the mechanical properties. In this way, the intensive research has been done to determine the effect of the use of filler on SiR. However, they still focused on the use of several types of commercial fillers such as silica, ATH, and carbon black.

This study introduces the application of coal fly ash (CFA) as a micro filler on SiR. The CFA is the industrial waste, mostly from the coal electrical power plant. It is abundantly available, very cheap even almost free. The objective of this study is to investigate the impact of the application of coal fly ash (CFA) micro filler on the dielectric property of silicone rubber.

The Silicon Rubber used in this study is POWERSIL XLR® 630 A/B produced by Wacker Chemie AG, Germany. The reason for this choice is due to it has no filler and widely used as outdoor insulation materials. The CFA used as a micro filler is obtained from local coal power plant in Aichi Prefecture, Japan. The Classification of CFA applied is F class, according to ASTM C612. The microstructure image of CFA obtained from Scanning Electron Microscope (SEM), JEOL-JCM 6000 Plus. The particle size distribution of CFA micro filler used in this study has been examined by using Laser Diffraction Size Analyzer, SALD-2300. The sample material consists of SiR as a matrix and CFA filler with different concentration and particle size distribution. The mixing ratio of the matrix, XLR 630 Powersil A, and B is 1:1. The composition of CFA filler in per hundred resin (phr) is 0 phr, 10 phr, 20 phr, 30 phr, 40 phr, and 50 phr with particle size distribution in two groups. The first group is CFA filler with the particle size ≤ 20 µm, obtained by using a mini sieve shaking machine (AS ONE). The second group is CFA filler with the condition as received from the local power plant with the particle ≤ 100 µm. Sample with 0 phr is a sample without CFA filler (neat sample) which is used as a reference.

The dielectric test results reveal that for CFA micro filler with the particle size 20 (first group), the relative permittivity increase from 2.8 to 3.2 with the increasing of CFA micro filler loading and tends to decrease when the CFA filler loading exceeds 30 phr. While for CFA filler with particle size 100 (second group), the relative permittivity decrease drastically when the CFA filler loading exceeds 20 phr. Dielectric loss tan increases with the increasing of CFA filler content and then tends to decrease when the CFA filler 40 phr for the second group. At low filler loading, surface and volume resistance for the first group increase with the increasing of filler loading and then drop when filler loading exceeds 20 phr. The maximum volume resistance and surface resistivity obtained was 27 Pand 5.8 P respectively by the application of the first group with filler loading 20 phr. The use of the second group of CFA filler increase the volume resistivity slightly but decrease surface resistivity. In general, the best improvement is achieved by the CFA filler with the particle size at the concentration of 20 phr.