• Transactions on Electrical and Electronic Materials
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• v.14 no.4
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• pp.199-202
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• 2013

In order to study the effect of reactive diluents on the electrical insulation breakdown strength and mechanical properties of, a polyglycol and an aliphatic epoxy were individually introduced to an epoxy system. Reactive diluents were used in order to decrease the viscosity of the epoxy system; polyglycol acted as a flexibilizer and 1,4-butanediol diglycidyl ether (BDGE) acted as an aliphatic epoxy, which then acted as a chain extender after curing reaction. The ac electrical breakdown strength was estimated in sphere-to-sphere electrodes and the electrical breakdown strength was estimated by Weibull statistical analysis. The scale parameters of the electrical breakdown strengths for the epoxy resin, epoxy-polyglycol, and epoxy-BDGE were 45.0, 46.2, and 45.1 kV/mm, respectively. The flexural and tensile strengths for epoxy-BDGE were lower than those of the epoxy resin and those for epoxy-polyglycol were lower than those of the epoxy resin.

• Macromolecular Research
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• v.11 no.3
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• pp.202-205
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• 2003

The reactive precursors, vinyl ethers, and epoxy-silicones, were synthesized. The vinyl ether monomers were prepared from primary alcohol and ethyl vinyl ether with mercury (II) acetate. The epoxy-functionalized silicones have been achieved by the controlled, rhodium-catalyzed, chemoselective hydrosilation of vinyl ether with siloxanes or silane. It was shown that the hydrosilation proceeds exclusively at the vinyl ether group of alkenyl vinyl ether without participation at the alkenyl group. The photoinduced cationic polymerization of these monomers was studied and found to be all highly reactive.

• Textile Coloration and Finishing
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• v.24 no.2
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• pp.145-151
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• 2012

Polymer alloys of poly(ethylene terephthalate)(PET) and nylon6(PA6) which were not miscible each other by themselves were successfully prepared through melt compounding using a twin-screw extruder by utilizing epoxy as reactive compatibilizer. At the epoxy(DGEBA) amount of 0.5~2wt%, the domain size(average diameter) of the discontinuous phase could be reduced up to 0.2${\mu}m$ from 1-5${\mu}m$ that of the simple blend without epoxy. The reaction was presumed to happen mostly at interphase from the result of maximum increase of melt viscosity at the middle range of PET/PA6 blend ratio. It is expected that alloy fibers of PET/epoxy/PA6 with enough mechanical strength for use can be prepared.

• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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• pp.77-80
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• 2014

The effect of reactive diluents on the ac electrical treeing in epoxy/nanosilicate systems was studied, in a needle-plate electrode geometry. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and layered silicate was used as a nano-sized filler. Polyglycol (PG) or 1,4-butanediol diglycidyl ether (BDGE) was introduced as a reactive diluent to the DGEBA/nanosilicate system, in order to decrease the viscosity of the nanocomposite system. PG acted as a flexibilizer, and BDGE acted as a chain extender, after the curing reaction. To measure the treeing propagation rate, a constant alternating current (ac) of 10 kV/4.2 mm (60 Hz) was applied to the specimen, in a needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. When 10 kV/4.2 mm (60 Hz) was applied, the treeing propagate rate in the DGEBA system was $1.10{\times}10^{-3}$ mm/min, and that in the DGEBA/PG system was $1.05{\times}10^{-3}$ mm/min. As 1.5 wt% of nanosilicate was added to the DGEGA/PG system, the propagation rate was $0.33{\times}10^{-3}$ mm/min. This meant that the nano-sized layered silicates would act as good barriers to treeing propagation. The effect of chlorine content was also studied, and it was found that chlorine had a bad effect on the electrical insulation property of the epoxy system.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.308-311
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• 2013

The effect of an electric field on the ac electrical treeing in various epoxy/reactive diluent systems was studied in a needle-plate electrode geometry. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE was acted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the treeing initiation time and the propagation rate, three constant alternating currents (ac) of 10, 13 and 15 kV/4.2 mm (60 Hz) were applied to the specimen, in a needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. When 10 kV/4.2 mm (60 Hz) was applied, the treeing initiation time and the propagation rate in the DGEBA system were 356 min and $1.10{\times}10^{-3}$ mm/min, respectively, those in the DGEBA/BDGE system were 150 min and $1.14{\times}10^{-3}$ mm/min, respectively. Those in the DGEBA/PG system were 469 min and $1.05{\times}10^{-3}$ mm/min, respectively. As 15 kV/4.2 mm (60 Hz) was applied, the propagation rate in the DGEBA system was $5.41{\times}10^{-3}$ mm/min, and that in the DGEBA/PG system was $1.42{\times}10^{-3}$ mm/min. These values meant that PG could be used as a reactive diluent in the DGEBA system, without the deterioration of the insulation breakdown property.

• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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• pp.87-90
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• 2014

The effects of electric field frequency on the ac electrical treeing phenomena in an epoxy/reactive diluent/layered silicate (1.5 wt%) were carried out, in needle-plate electrode arrangement. A layered silicate was exfoliated in an epoxy base resin, by using our ac electric field apparatus. To measure the treeing propagation rate, constant alternating current (AC) of 10 kV with three different electric field frequencies (60, 500 and 1,000 Hz) was applied to the specimen, in needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. As the electric field frequency increased, the treeing propagation rate increased. At 500 Hz, the treeing propagation rate of the epoxy/PG/nanosilicate system was $0.41{\times}10^{-3}$ mm/min, which was 3.4 times slower than that of the epoxy/PG system. The electrical treeing morphology was dense bush type at 60 Hz; however, as the frequency increased, the bush type was changed to branch type, having few branches, with very slow propagation rate.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.317-320
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• 2013

Partial discharge resistance for the epoxy systems with two diluents was investigated in the rod-plane electrodes arrangement, and the effect of electric frequency on the partial discharge resistance was also studied. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE was acted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the partial discharge resistance, 5 kV alternating current (ac) with three different frequencies (60, 500 and 1,000 Hz) was applied to the specimen in a rod-plane electrode arrangement, at $30^{\circ}C$. PG had a good effect, while BDGE had a bad effect on the partial discharge resistance of the DGEBA system, regardless of the electric frequency.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1030-1035
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• 1994

Curing behavior and glass transition temperatures of epoxy resins into which reactive diluents were added to control processability were investigated. Heat of cure generated of the epoxy resin was reduced with butyl glycidyl ether(BGE) and phenyl glycidyl ether(PGE) contents. $T_g$ of the resin was decreased with the amount of reactive diluents and it was attributed to increased molecular weight between crosslink points. Cure kinetics of the resins was studied employing autocatalytic reaction model and found that reaction constants decreased as the contents of reactive diluent was increased.

• Journal of Adhesion and Interface
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• v.25 no.1
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• pp.162-168
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• 2024

The effect of maleinized polybutadiene (MPB) on the mechanical properties of epoxy resins including adhesion strength, elongation and impact peel resistance was investigated in this study, in which MPB is an anhydride-functionalized polybutadiene prepolymer. Different molecular weights (3.1K and 5.6K) of MPB were added to diglycidyl ether bisphenol-A (DEGBA), an epoxy resin, to increase its impact peel strength and elongation. At various loading percent (5, 10, 15, 20 and 25 wt%) of MPB in the epoxy resin, significant improvements of mechanical properties were observed. According to the comparative analysis results, the modified epoxy system with 15 wt% (3.1K) MPB exhibited the highest lap shear strength, about 40% higher than that of neat epoxy. The tensile strength and elongation steadily and simultaneously increased as the loading percent of MPB increased. The impact peel strengths at low (-40℃) and room (23℃) temperatures were substantially improved by MPB incorporation into epoxy resins. Reactive and flexible MPB prepolymer seems to construct strong nano-structured networks with rigid epoxy backbones without sacrificing the tensile and adhesion strengths while increasing impact resistance/toughness and elongation properties. For higher impact peel while maintaining adhesion and tensile strengths, approximately 10-15 wt% MPB loading in epoxy resin was suggested. Consequently, incorporation of functionalized MPB prepolymer into epoxy system is an easy and efficient way for improving some crucial mechanical properties of epoxy resins.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.213-218
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• 2013

In this study, epoxy/mica composite was prepared by mixing with mechanical stirrer together with homogenizer, and the effect of amino-type silane coupling agent was also studied. To reduce the viscosity without any decrement of other properties, 1,4-Butanediol diglycidyl ether (1,4-BDGE) as an aliphatic epoxy reactive diluent was introduced to the epoxy/mica composite in order to use as vanish for high voltage motor and generator stator winding. It was confirmed by scanning electron microscopy (SEM) observation that interfacial characteristics between organic epoxy and inorganic mica was modified by coupling agent treatment so that glass transition temperature increased, and tensile strength and electrical breakdown strength increased. The properties were estimated by Weibull statistical analysis and the ac electrical breakdown strength was 20.2% modified by treating silane coupling agent.