• Elastomers and Composites
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• v.7 no.1
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• pp.21-37
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• 1972

We have studied the blending effects of Diene NF 35R and Turfdene 1000R at various blending ratios 100/0, 70/30, 50/50, 30/70, 0/100, and of carbon black NAF and ISAF at various compounding ratios of 55 PHR, 65PHR, 75PHR for tyre tread rubber. As the results, it was found that; 1. For tyre tread rubber, as the blending ratio, Diene NF 35R/Turfdene 1000R, indicated 30/70, the physical properties we examined were most excellent. 2. Excellent result was obtained in case of carbon black compounding ratio of 63PHR. The compounding of ISAF made better result than that of HAF for tensile strength, tearing strength, and abrasion quantity. 3. Heat buildup obtained from compounding carbon black HAF indicated low temperature than that from compounding carbon black ISAF. As the compounding amount of carbon black increased, the heat buildup improved, and as the blending amount of Diene NF 35R decreased, the heat buildup dropped. 4. Carbon black was more efficient to Turfdene 1000R than to Diene NF 35R. 5. In this pysical properties, mooney viscosity, and mooney scorch time, as the compounding amount of carbon black increased, the values of mooney viscosity increased, but that of mooney scorch time dropped.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.827-834
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• 2011

Epoxy/graphite/expanded graphite composites have been prepared in various weight ratios and thermal degradation and electrical properties were estimated in order to use for the bipolar plate materials in PEMFC. Thermogravimetric analysis (TGA) showed that the epoxy/graphite system cured by a curing agent GX-533 was most proper because its weight loss until $80^{\circ}C$ at which PEMFC would be operated was 0.3 wt%, and differential scanning calorimetry (DSC) analysis showed its cure temperature would be sufficient at $80^{\circ}C$. The activation energy for the cure reaction was 132.0 kJ/mol and the pre-exponential factor was $1.76{\times}10^{17}min^{-1}$. Electrical conductivity on the surface of the bipolar plate prepared under a pressure of 200 $kgf/cm^2$ was increased from 4 to 25 $S/cm^2$ by increasing expanded graphite (EG) content from 50 phr to 90 phr. The percolation threshold was initiated around 75 phr and the corrosion rate at 80 phr was 1.903 $uA/cm^2$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.5
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• pp.494-498
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• 2022

In this study, SiO₂ 20 phr, ATH 70 phr, and platinum flame retardant were mixed with raw silicone rubber and -10 kV was applied to measure electrostatic charge attenuation voltage, surface resistance, and volume resistance, and the following conclusions were obtained. When the platinum flame retardant was 0 phr, the humidity 74.6% and the temperature was 21.8℃, the potential was half-reduced to 0.63 kV, 0.57 kV, and 0.44 kV when the applied voltage was changed from -10 kV to -8 kV, and the time halved to 50% was increased to 2.40 seconds, 2.47 seconds, and 2.61 seconds. It was confirmed that as the platinum flame retardant increased from 0.1 to 0.3 phr, the potential half-reduced to 0.67 kV, 0.60 kV, and 0.595 kV decreased, and the charge potential attenuation time half-reduced to 50% decreased to 3.44 seconds, 1.78 seconds, and 1.60 seconds. It was confirmed that the surface resistance increased as the humidity decreased, and the volume resistance decreased as the platinum flame retardant increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.219-222
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• 1998

In this study, The water tree characteristics were investigated when crosslinking coagent was added in XLPE/EnBA blends. When XLPE was blended with EnBA, there was a decrease of water tree length as an increase of nBA contents in XLPE/EnBA20 blends. The effect of crosslinking coagent. A was better than those of other crosslinking coagents B, C and D in water tree retardation. In case of XLPE/EnBA/Crosslinking coagent blends, water tree length was increased as the crosslinking coagents were increased from 0.2 to 2 phr in 2.0 phr DCP content. To clarify the effects of crosslinking coagent, the DCP contents were changed from 1.5 to 2.0 par in the same crosslinking coagent contents. Then, there was a decrease of water tree length as an increase of crosslinking coagent contents in 1.5 and 1.8 phr DCP contents.

• Advances in materials Research
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• v.12 no.1
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• pp.1-13
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• 2023

The combination of cobalt ferrite and natural rubber has a potential to enhance the functional properties of rubber ferrite composites available on the market. In this study, cobalt ferrite was synthesized by the sol-gel method with tapioca starch as a cheating agent and then incorporated into natural rubber using an internal mixer. The curing characteristics, magnetic hysteresis, complex permeability, and permittivity of the rubber ferrite composites were studied as a function of the loading from 0 to 25 phr. The cure time and scorch time tended to reduce with the addition of non-reinforced cobalt ferrite fillers. The remanent and saturation magnetizations were linearly proportional to the cobalt ferrite loading, consistent with the rule of mixture. On the other hand, the increase in cobalt ferrite loading from 5 to 25 phr slightly affected the coercive field and the complex permeability. Using the maximum loading of 25 phr, both real and imaginary parts of the permittivity were significantly raised and reduced with the frequency in the 10-300 MHz range.

• Elastomers and Composites
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• v.8 no.1
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• pp.33-51
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• 1973

We have studied the blending effects of Diene NF 35 R and Alfin 1530 at various blending ratios, 100/0, 70/30, 50/50, 30/70, 0/100, and of carbon black HAF-HS and ISAF-HS at various compounding ratios of 45 PHR, 55 PHR, 65 PHR, for tyre tread rubber. As the results, it was found that; 1. For tyre tread rubber, as the blending ratio, AR 1530/Diene NF 35R, indicated 70/30, the physical properties we examined were most excellent. 2. Excellent result was obtained in the case of carbon black compounding ratio of 55 PHR. The compounding of ISAF-HS made better result than that of HAF-HS for tensile strength, but the compounding of HAF-HS made better result than that of ISAF-HS for tearing strength and best result for abrasion quantity. 3. Heat buildup obtained from compounding carbon black HAF-HS indicated low temperature than that from compounding carbon black HAP-HS. As the compounding amount of carbon black increased, and as the blending amount of AR 1530 decreased, the heat buildup increased. 4. Carbon black was more efficient to AR 1630 than io Diene NF 35 R. 5. In the physical properties, mooney viscosity and mooney scorch time, as the compounding amount of carbon black increased, the values of mooney viscosity increased, but that of mooney scorch time had a max. point at the compoundiug amount of carbon black, 55 PHR.

• Textile Coloration and Finishing
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• v.33 no.2
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• pp.79-86
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• 2021

This study investigated the effect of a pigment (C. I. Pigment Red 122) addition on mechanical properties of the epoxy resin, diglycidyl ether of bisphenol F (DGEBF) and G640 curing agent. The K/S value, thermal properties, tensile properties, and fracture toughness of the prepared epoxy samples were evaluated. When the pigment was added to the DGEBF/G640 epoxy system, the color of the epoxy resin changed to red from transparent and yellowish color, and the K/S value in the red region increased as the pigment content increased. When the pigment content was increased up to 0.1 phr, the tensile strength was improved up to 21.8 %, whereas the pigment content was over 0.1 phr, the tensile strength decreased. The fracture toughness was improves up to 23.1 % until the amount of pigment added was up to 0.2 phr, and then decreased when the amount of the pigment added was more than 0.2 phr. This attributed to the aggregation of the pigments in the epoxy resin when the amount of the pigment added was more than 0.2 phr. Therefore, the coloration of the epoxy resin with an organic pigment must be carried out very carefully because the coloration of epoxy resin affects its mechanical properties.

• Advances in materials Research
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• v.3 no.3
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• pp.175-183
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• 2014

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide ($MePPh_3I$) by Wittig reaction ($0^{\circ}C$ for 2 hrs, $N_2$ atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer ($180^{\circ}C$ for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

• Polymer(Korea)
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• v.28 no.2
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• pp.162-169
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• 2004

Poly[styrene-b-(ethylene-1-butene)-b-styrene] triblock copolymer (SEBS) was functionalized with 0 to 3.0 phr maleic anhydride and the amount of dicumyl peroxide used as an initiator was varied from 0 to 0.3phr. The gel content of the modified SEBS was determined by xylene extraction and poly(oxymethylene) was blended with the modified SEBS. The impact, tensile, flexural strength and morphologies of the blends were investigated. The Izod impact strength of poly(oxymethylene) was improved through its blending with modified SEBS. However, the Izod impact strength of poly(oxymethylene)/modified SEBS blend decreased above 5% modified SEBS content. Regarding the effect of dicumyl peroxide content on the Izod impact strength, the blend had a maximum Izod impact strength when poly(oxymethylene) was blended with modified SEBS prepared with 0.1 phr dicumyl peroxide. It was also confirmed by SEM micrographs that the average particle size of modified SEBS in poly(oxymethylene)/modified SEBS blends was smaller than that of SEBS in poly(oxymethylene)/SEBS blends.

• Elastomers and Composites
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• v.50 no.4
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• pp.279-285
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• 2015

This study examined the mechanical properties and the flame retardant properties of CR rubber containing inorganic flame retardant with various contents of aluminium trihydroxide (ATH, $Al(OH)_3$). The content of aluminium trihydroxide was added in 0, 30, 50, 70 and 100 phr for T1~T5 samples. It was found that increasing the amount of addition over 30 phr resulted in decreasing the mechanical properties. On the other hand in oxygen index measurements T1 sample showed a value of 38.6%, indicating the improvement of flame retardant properties showed a value of 49.7~64.2%. In case of burn test, it was confirmed that CR rubber containing over ATH 50phr content showed performance corresponding to that of first grade fire-resistance.