• Elastomers and Composites
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• v.57 no.3
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• pp.107-113
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• 2022

The effects of fillers [talc, calcium carbonate, glass fiber, and EBR (ethylene-butene rubber)] on the shrinkage and mechanical properties of injection-molded polypropylene composites were investigated. The shrinkage correlated with the shape of the filler particles: at the same amount added, glass fibers with a large aspect ratio had the greatest effect on the shrinkage of polypropylene composites, followed by flake-shaped talc and granular calcium carbonate. It was confirmed that the addition of EBR rubber as an impact strength modifier reduced shrinkage proportionally to the added content. In addition, the addition of glass fiber resulted in the greatest increases in tensile and flexural strengths.

• Progress in Superconductivity and Cryogenics
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• v.16 no.1
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• pp.14-18
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• 2014

The mechanical, electrical and thermal characteristics of insulating materials may significantly affect the performance and reliability of electrical devices using superconductors. General method to provide insulating layer between coated conductors is wrapping coated conductor with Kapton tape. But uniform and compact wrapping without failure or delamination in whole coverage for long length conductor is not a simple task and need careful control. Coating of insulating layer directly on coated conductor is desirable for providing compact insulating layer rather than wrapping insulating layers around conductor. Ceramic added polymer has been widely used as an insulating material for electric machine because of its good electrical insulating properties as well as excellent heat resistance and fairy good mechanical properties. The insulating layer of coated conductor should have high breakdown voltage and possesses suitable mechanical strength and maintain adhesiveness at the cryogenic temperature where it is used and withstand stress from thermal cycling. The insulating and mechanical properties of polymer can be improved by adding functional filler. In this study, insulating layer has been made by adding ceramic particles such as $SiO_2$ to a polymer resin. The size, amount and morphology of added ceramic powder was controlled and their effect on dielectric property of the final composite was measured and discussed for optimum composite fabrication.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.822-824
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• 1998

The lithium polymer battery with polymer electrolyte is expected as a safe and long cycle life battery. This paper reports primarily the recent development results of a solid polymer electrolyte, which is a key point of the secondary battery system. The new type of polymer electrolyte was prepared under a dry Ar atmosphere by dissolving $LiCIO_4$ in a matrix of EC, PC and then dispersing polyacrylonitrile(PAN). Also adding some inorganic filler $Al_2O_3$. The dispersed solution heated at $120^{\circ}C$. The polymer electrolyte were characterized by EIS(Electrochemical Impedance Spectroscopy), TGA(Thermo Gravimetric analysis), DMA(Dynamic Mechanical Analyzer), DSC (Differential Scanning Calorimetry). The lithium ion yield is 0.29 when PAN-$Al_2O_3$ which was applied DC 5mV. The ionic conductivity of PAN, PAN-$Al_2O_3$ polymer electrolytes were showed $1.0{\times}10^{-4}S/cm$, $8.4{\times}10^{-4}S/cm$ at room temperature. When inorganic filler was added in the polymer electrolyte, ionic conductivity and lithium yield more larger than without inorganic filler.

• Elastomers and Composites
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• v.54 no.2
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• pp.142-148
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• 2019

In this study, the effects of filler particle size and shape on the physical properties of silicone rubber composites were investigated using inorganic fillers (Minusil 5, Celite 219, and Nyad 400) except silica, which was already present as a reinforcing filler of silicone rubber. Fillers with small particle sizes are known to facilitate the formation of the bound rubber by increasing the contact area with the polymer. However, in this experiment, the bound rubber content of Celite 219-added silicone composite was higher than that of Minusil 5-added silicone composite. This was attributed to the porous structure of Celite 219, which led to an increase in the internal surface area of the filler. When the inorganic fillers were added, both thermal decomposition temperature and thermal stability were improved. The bound rubber formed between the silicone rubber and inorganic filler affected the degree of crosslinking of the silicone composite. It is well-known that as the size of the reinforcing filler decreases, the reinforcing effect increases. However, in this experiment, the hardness of the composite material filled with Celite 219 was the highest compared to the other three composites. Furthermore, the highest value of 2.19 MPa was observed for 100% modulus, and the fracture elongation was the lowest at 469%. This was a result of excellent interaction between Celite 219 filler and silicone rubber.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.769-774
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• 2002

In this study, methyl methacrylate (MMA)- modified polyester polymer concrete, in which the MMA was added to the unsaturated polyester resin, was developed for improving the early-age strength and the workability of the conventional polymer concrete, binder of which was the unsaturated polyester resin. Then the fundamental properties of the polymer concrete such as workability and strength were surveyed. The experimental results showed that the workability was remarkably improved as the MMA contents increased, and the filler-binder ratio was turned out to be important factor for the workability. Slump prediction equation was derived by the regression analysis based on MMA content and filler-binder ratio. Furthermore, early-age strength was greater when the MMA content were increased in the range of 20-40 % but the strength rather showed a tendency of decrease when the MMA content was 50 %.

• Macromolecular Research
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• v.11 no.6
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• pp.506-510
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• 2003

A Zn ion-coated nanosilica filler has been developed and tested, in chlorosulfonated polyethylene (CSPE) and polychloroprene (CR), as a vulcanizing activator, cum was reinforcing filler. In this study, ZnO was replaced by the Zn ion-coated nanosilica filler with an aim of studying the dual role of this nanofiller in CSPE and CR. In the case of CSPE vulcanizates, the presence of MgO deteriorated the state and rate of cure when the Zn ion-coated nanosilica filler was used, but in the case of CR it improved the state of cure and enhanced the modulus and tensile strength. The Zn ion-coated filler proved to be a better reinforcing-cum-curing agent than was externally added ZnO and NA-22 also proved to be a better curative in the presence of the Zn ion-coated nanosilica filler for both CSPE and CR.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.606-616
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• 2003

Purpose : The purpose of this study was to research the properties of some chemically cured methacrylate polymers such as MMA, HEMA, TEG-DMA, bis-GMA, GMA. Material and Method : 5 kinds of methacrylates were selected and added 2% tertiary amine and benzoyl peroxide to make a chemically curable polymer 25 micron crushed silicas which are treated with silane were selected as filler, they were added into methacrylate monomer until the consistency did not changed by the load of 500gram. All of the experimental resins were 5 kinds, and a serial test was done with 3 kinds of items including the filler contents, the tensile strength, and the bond strength. The number of specimen were 10 for each group. Filler contents were obtained by reducing the specimens to ashes at $600^{\circ}C$ for 1 hour. The specimens with the dimension of 6mm in diameter and 3mm thick were immersed in $37{\pm}1^{\circ}C$ distilled water for 24 hours before test, and tensile strength were measured with cross-head speed 1mm/min. Shear bond strength were mea sured on the specimens attached to bovine enamel etched with 37% phosphoric acid for 1 minute. Results : 1. Maximum filler incorporation was the highest as 75.5% on MMA, and the least as 53.4% on bis- GMA(p<0.0001). 2. The tensile stregth were MMA 141.3, GMA 154.3, TEG-DMA 157.4, bis-GMA 161.4 MPa, and HEMA showed the highest value, 226.9MPa(p = 0.0004). 3. The bond strength were GMA 10.1, TEG-DMA 11.7, HEMA 12.2, bis-GMA 13.3 MPa, and MMA showed the highest value, 15.3MPa, however statistical significances were not (p =0.3838), 4. TEG-DMA and HEMA were not different on the aspect of maximum filler contents and shear bond strength(p>0.05). Conclusion : HEMA can be used as an another diluent substituting TEG-DMA with the increased strength and with the constant bond strength and the constant filler contents.

• Macromolecular Research
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• v.12 no.4
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• pp.399-406
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• 2004

Glass-like carbon precursors shrink significantly during curing and carbonization, which leads to crack formation and bending. Cured furan resin powder and ethanol were added to furan resin to diminish the weight loss, to suppress the shrinkage and bending, and to readily release the gases evolved during polymerization and curing. Curing and carbonization were controlled by pressure and slow heating to avoid damage to the samples. The effect of the filler and ethanol on the fabrication process was examined by measuring the properties of the glass-like carbon, such as the specific gravity, bending strength, electrical resistivity, and microstructural change. The specific gravities of the filler-added glass-like carbons were higher than those of the ethanol-added samples because of the formation of macropores from the vaporization of ethanol during the curing and polymerization processes. Although the ethanol-added glass-like carbons exhibited lower bending strengths after carbonization than did the filler-added samples, the opposite result was observed after aging at 2,600$^{\circ}C$. We found that the macropores created from ethanol were contracted and removed upon heat treatment. The electrical resistivity of the glass-like carbon aged at 2,600$^{\circ}C$ was lower than those of the samples carbonized at 1,000$^{\circ}C$. We attribute this phenomenon to the fact that aging at high temperature led to well-developed microstructures, the removal of macropores, and the reduction of the surface area.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.978-983
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• 2014

The polymer nano composite possess good priority recently for engineering applications. Especially the electrical insulating materials attract the high performance of nano composites. In this work the ballmill synthesiation process of nano sized Alumina ($Al_2O_3$), the preparation of new nano composite material with an content of enamel and synthesized Alumina as 1wt%, 3wt% and 5wt%. Experimental investigation has been carried out for the prepared nano composites materials with respect to dielectric parameter measurements such as dielectric loss (tan ${\delta}$), dielectric constant (${\varepsilon}$), dielectric strength under various temperature. The partial discharge level also measured for all the samples and the PD inception voltage is also observed and compared. Weight loss of the material has been analyzed through TGA. It has been experimentally proved that 3wt% of Alumina nano filler added enamel has significant improvement in the dielectric and thermal properties.

• Composites Research
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• v.19 no.2
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• pp.7-12
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• 2006

Graphite particle/carbon fiber hybrid conductive polymer composites were fabricated by the compression molding technique. Graphite particles were mixed with an epoxy resin to impart the electrical conductivity in the composite materials. In this study, graphite reinforced conductive polymer composites with high filler loadings were manufactured to accomplish high electrical conductivity above 100S/cm. Graphite particles were the main filler to increase the electrical conductivity of composites by direct contact between graphite particles. While high filler loadings are needed to attain good electrical conductivity, the composites becomes brittle. So carbon fiber was added to compensate weakened mechanical property. With increasing the carbon fiber loading ratio, the electrical conductivity gradually decreased because non-conducting regions were generated in the carbon fiber cluster among carbon fibers, while the flexural strength increased. In the case of carbon fiber 20wt.% of the total system, the electrical conductivity decreased 27%, whereas the flexural strength increased 12%.