Papers by Keyword: Silicone Rubber

Abstract: High-voltage electrical equipment insulation often uses composite materials like epoxy resin, cross-linked polyethylene, polyurethane, and silicone rubber as encapsulation. 3D printing technology offers a more efficient and cost-effective solution, producing intricate elements without cutting and casting. Research shows that 3D printed materials have comparable properties to polymer-based insulation, but further testing is needed to evaluate their resistance to harsh environmental conditions. This research investigates the arc resistance properties of 3D printed insulation materials for outdoor high-voltage applications, assessing their suitability for outdoor applications. The wet and dry arc resistance tests were performed in accordance with ASTM D495-99 and IEC-60587. The present work investigated three varieties of samples: polylactic acid, epoxy resin, and silicone rubber. The results of the tests reveal that polylactic acid test samples have average wet and dry arc resistance times of 2.5 hours and 1.4 seconds, which is less than silicone rubber and epoxy resin. Additional research is required to comprehend the behavior of arc formation in polylactic acid insulation materials for high-voltage 3D printing applications.

Abstract: Thermal conductivities of silicone rubber filled with Al₂O₃ were prepared. Thermal conductivity experimental results obtained were analyzed using the Nielsen and Agari models to explain the effect of Al₂O₃ filler on the formation of thermal conductive networks. Thermal conductivities increased with the adding of mixed Al₂O₃ of large and small sizes fillers. The scanning electron microscopy (SEM) showed that it is the optimum particle sizes and quantities that made the filler packing closer, which thus leads to formation of more thermal conductive chains.

Abstract: Silicone rubber (SR) and hydroxyapatite (HA) are two well-known material that have been used as bone replacement. The flexibility and compatibility of SR and HA respectively, shows great performance and improvement in medical application. This paper investigate the mechanical properties of SR and HA composite with various phr loading of HA (0 - 30 phr). The results indicate that, HA loading phr of 25 phr and 30 phr were in the range of tensile strength of 5.76 MPa and 3.15 MPa respectively. Also, the hardness value of all the percentage loading of HA were above the hardness value of human vertebrae cancellous bone.

Abstract: The investigation of silicone rubber properties with the presence of platinum catalyst at different temperature using molecular dynamic simulation was conducted. Visual observation shows that structuring of silicone rubber occurs in the cell where the molecules aggregates closer compared to at the beginning of the simulation and at higher platinum concentration, silicone rubber molecules are more closely packed together. The diffusion coefficient of silicone rubber are the highest in a 10% platinum concentration followed by 25% and lastly 50% indicating that it is harder for the silicone rubber molecules to move from its original position in the system as the platinum concentration increases. Structural changes was also investigated through radial distribution function (RDF) where the position of peaks did not change with time but there is changes observed in the intensity of the peak. At a constant temperature 50°C, it was observed that the intensity of the peak at 1.10Å radius was the highest in the presence of 50%Pt followed by 25%Pt and 10%Pt. This indicates that higher numbers of silicone rubber molecules are present in a 1.10Å radius from the reference molecules in a system with higher concentration of platinum.

Abstract: Crosslinker (polyvinylsilicone oil, C gum) and curing agent (2, 5-bis (tert-butyl peroxy)-2, 5-dimethyl hexane, DBPMH) were used to change the crosslink density of the thermal conductivity of silicone rubber filled with Al₂O₃. The results show that the thermal conductivity of silicone rubber changed with its degree of crosslinking. When the Al₂O₃ loading was 5 vol. % and a completely continuous conducting network had not formed, the thermal conductivity of the vulcanizates decreased with increasing crosslink density. The thermal conductivity of the vulcanizate with a suitable amount of C gum increased to 53%, and the tensile strength increased by 0.8 MPa compared to the vulcanizate without C gum. When the Al₂O₃ loading was 30 vol. % and a completely continuous conducting network had formed, the crosslink density of vulcanizates changed as the amount of DBPMH changed. The thermal conductivity of vulcanizates first decreased and then increased with increasing crosslink density. There was a valley value in the thermal conductivity–crosslink density curve.

Abstract: Germs are present in all areas of everyday life and can lead to dangerous infections. Surfaces with antimicrobial properties are used to reduce the risk of infection in sanitary facilities and hospitals. Apart from the addition of biocides or antibiotic agents to synthetic materials, research shows that it is possible to use the semiconductor titanium dioxide (TiO₂) to generate antibacterial surfaces. Photocatalytically active TiO₂ leads to the development of reactive oxygen species (ROS) that are able to kill germs. The aim of this research is to use TiO₂ to generate antibacterial bulk material. Nanostructured TiO₂ particles were incorporated into silicone rubber to obtain a photocatalytic active polymer surface. High temperature vulcanizing (HTV) silicone rubber was used as a matrix material, and samples with 10 wt% of TiO₂ were produced. The distribution of TiO₂ particles in the matrix was analyzed via light microscopy. The photocatalytic activity on the surface of the test samples was studied via microbial testing with E.coli bacteria. The samples showed different intensities of the photocatalytic effect depending on the type of additive. The effort to create a germ reducing silicone rubber surface by using TiO₂ as an additive was successful.

Abstract: In order to solve the thermal aging problem of silicone rubber insulation layer of 220 kV integral prefabricated cable joints, the mass loss and thermal gravimetric (TG) were tested. The thermal aging mechanism of thermal degradation reaction of silicone rubber molecular chains was analyzed by gel content test and infrared spectrum test (IR). The results showed that the cross-linked network of the molecular chain structure gradually deteriorates, resulting in the increase of mass loss rate and the decrease of thermal stability. The results also showed that the increase of dual peak of differential thermal weight (DTG), the decrease of initial decomposition temperature and the remaining mass. With increasing aging temperature and aging time, the aging would be accelerated. These properties could reflect the degree of thermal aging of silicone rubber insulation layer. The results could also provide theoretical support for the preparation, operation and maintenance for silicone rubber cable joints.

Abstract: A two-step solvothermal method was employed to synthesize the Graphene/Fe₃O₄/BaTiO₃ (GFT). X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra are used to observe the microstructure and magnetic properties of GFT, and the nanoparticles of Fe₃O₄ and BaTiO₃ were uniformly deposited on the surface of the graphene nanosheets. Then GFT filler and the silicone rubber were mixed to manufacture the electromagnetic shielding materials. The vector network analyzer was employed to evaluate the electromagnetic shielding effectiveness of the modified electromagnetic shielding materials. The influence of the mole ratio of the GFT constituents, the mass content of the filler on the electromagnetic shielding effectiveness was studied between 1 GHz and 20 GHz. It is shown that the GFT/silicone rubber has the best electromagnetic shielding effectiveness for 24:1:1 of graphene: Fe₃O₄: BaTiO₃ and 16 % GFT.

Abstract: Nature-inspired superhydrophobic surfaces have received immense industrial and academic interest due to their non-wettability and self-cleaning properties. To fabricate superhydrophobic silicone rubber surfaces, a simple, environmentally friendly atmospheric-pressure plasma treatment was applied. The effect of diverse plasma processing parameters on the final wettability behavior of the substrates, including plasma power, plasma frequency, number of passes, plasma jet speed, plasma cycle time and distance between the nuzzle outlet and substrate, were analyzed by means of design of experiments (DoE). Surface chemical characterization illustrated the influence of plasma treatment on the chemical composition of the produced silicone rubber. Furthermore, the presence of microstructures as well as the chemical composition of the surface was confirmed using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analysis.

Abstract: A facile method is introduced for production of micro-nanostructured silicone rubber surfaces by means of direct replication using a compression molding system. The fabricated samples possessing surface roughness display water contact angle of more than 160o and contact angle hysteresis (CAH) and sliding angle of less than 5o. Such low surface wettability of silicone specimens verifies the induced superhydrophobic property. Chemically etched aluminum surfaces could work excellently as templates whose patterns were replicated on the rubber surfaces successfully. Various etching conditions were examined. Surface characterization techniques revealed the presence of micro-nanostructures on the produced silicone surfaces.