• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.613-619
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• 2016

The aim of this study is to improve of dielectric properties using epoxy/nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2 g). This paper deals with the effects of dielectric properties(${\epsilon}^{\prime}_r$ and $tan{\delta}$) for epoxy/nano alumina contents (1,3 phr) and GDE addition (1,2 g)composites. 5 kinds specimen were prepared with containing epoxy resins, epoxy nano alumina composites. Average particle size of nano used were 30 nm. The nano alumina used were gamma phase particles of spherical shape. The suppression of epoxy chain motion by addition of nano alumina+GDE decreased dielectric loss and relative permittivity magnitude.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.352-356
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• 2014

PDMS modified epoxy resin with epoxy group (EMPDMS) was prepared from the reaction of ${\alpha},{\omega}$-aminopropylpolydimethylsiloxane and diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin, and PDMS modified epoxy hybrid compound (EMPDMSH) was prepared by introducing alkylesteraminopropyl alkoxy silane to EMPDMS. Their structures were characterized using FT-IR, $^1H$-NMR and $^{29}Si$-NMR. Coating materials were prepared by mixing EMPDMSH base and solvent. Physical properties of the coating materials coated on epoxy/glass fiber composite film were measured according to the content of PDMS in EMPDMSH. Contact angle of coating film was increased 30 to 71 degree. Adhesive property of coating film was 5B degree better then epoxy or acrylate coating materials, and surface roughness was decreased as increasing in EMPDMSH.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.79-85
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• 2017

Multi-Walled Carbon Nanotubes (MWCNTs) were modified with epoxy and aminosilane diethanolamine (DEA), and nanocomposites of poly(butylene adipate-co-terephthalate) (PBAT) and the modified MWCNTs were prepared with the aim of improving the physical properties of biodegradable PBAT. The physical and the thermal properties of the PBAT/MWCNT nanocomposites were investigated using various techniques. Fourier transform infrared spectroscopy measurements revealed that the MWCNTs were efficiently modified with DEA. Scanning electron micrographs of the nanocomposites indicated that the modified MWCNTs were dispersed homogeneously in PBAT. The thermal stability of the nanocomposite decreased with increase in the content of epoxy-MWCNT-DEA due to the poor thermal stabilities of epoxy and amino silane DEA. However, the surface hydrophobicity of the nanocomposite increased. The highest stress (170% of PBAT) was observed when the content of epoxy-MWCNT-DEA in the nanocomposite was 2 wt%.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.103-107
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• 2006

It is well-known that the mechanical properties of MMT(montmorillonite) nanocomposites are better than those of conventional composites. In this study, tensile tests were performed to determine the effect of silane modification of MMT and its weight ratio on the tensile properties of MMT/epoxy nanocomposites. It was found that the tensile strength and the elastic modulus of MMT/epoxy nanocomposites increased with increasing weight ratio of MMT. The elastic modulus of silane-modified MMT/epoxy nanocomposites was higher than that of untreated MMT/epoxy nanocomposites, irrespective of weight ratio.

• 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.

• Polymer(Korea)
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• v.25 no.3
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• pp.414-420
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• 2001

In this study, the effect of type of intercalant on properties of epoxy nanocomposites was investigated. Cetyltrimethylammoniumbromide (CTMA) as an alkylammonium salt and cetyltributylphosphoniumbromgide (CTBP) as an alkylphosphonium salt were used to modify sodium montmorillonite. In the case of using the CTMA as an intercalant, the long spacing of the silicate layer was about $18.8 {\AA}$. When CTBP was used, the long spacing of the silicate layer ( $23.8{\AA}$) was higher than that of CTMA. From these results, the characteristic length of the modified silicate was found to be significantly affected by the type of intercalant. We also noted that the thermal stability of modified MMT were affected by the type of intercalant, but in the epoxy nanocomposites prepared from the modified MMT, the thermal stability remains almost the same regardless of the type of intercalant. Tensile strength and elongation of epoxy nanocomposites prepared from MMT modified with CTBT were found to be higher than those of the epoxy nanocomposite prepare with WT modified with CTMA.

• Journal of Adhesion and Interface
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• v.23 no.2
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• pp.44-52
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• 2022

Epoxy resin has the disadvantage of being easily destroyed by instantaneous impact due to its high crosslinking density despite its high glass transition temperature (T_g) and excellent properties. To compensate for this, in this study, polyol was synthesized by ring opening polymerization of propylene glycol (PPG) diamine, Jeffamine D 2000 and propylene carbonate, and urethane modified epoxy was synthesized using this. The properties of the synthesized urethane modified epoxy were confirmed by FT-IR, H-NMR. To confirm the degree of improvement in impact resistance as an adhesive, a urethane modified epoxy adhesive was prepared by mixing a digylcidyl ether bisphenol A (DGEBA) with curing agent and curing accelerator. Properties test of urethane modified epoxy were shear strength, tensile strength and impact strength. As a result, excellent results were obtained in all test when the ratio of DGEBA : urethane modified epoxy was 8:2.

• Tribology and Lubricants
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• v.21 no.6
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• pp.302-305
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• 2005

Various carbon nanotubes (CNTs) are added into the epoxy matrix as reinforcements to investigate the effect on the wear behavior. Effects to the tribological properties of different loading concentrations and types of surface modification are investigated by using a linear reciprocal wear tester. As increasing the concentration of CNTs shows the reduction of the wear loss. Moreover, surface modified CNTs give better tribological property than as produced CNTs. It is due that the functional groups on the surface of CNTs increase the interfacial bonding between CNTs and epoxy matrix through chemical bonding. Changes in worn surface morphology are observed by optical microscope and SEM to investigate the wear behavior. CNTs in the epoxy matrix near the surface are exposed and it becomes the lubricating working film on the worn surface. It reduces the friction and results in the lower surface roughness morphology in the epoxy matrix as increasing the contents of the CNTs.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.22-23
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• 2017

The purpose of this study is to ascertain self-healing function on microcracks in bisphenol F-type epoxy-modified mortars using expansive admixtures. The specimens are prepared with various polymer-binder ratios of 0, 5, 10, 20%, expansive admixture contents of 0% and 10%, a sodium carbonate content of 0.25%, and subjected to exposure conditions of CR1, CR2, CR3 and CR4. The specimens are tested for self-healing effect, porosity and FE-SEM analysis. As a result, self-healing effects of bisphenol F-type EPMMs with expansive admixtures are visible in all of the outdoor exposure conditions. In particular, exposure conditions of CR3 and CR4 are most noticeable. And the porosity of EPMMs is reduced with an increase in the polymer-binder ratio, and is considerably smaller than that of unmodified mortar.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.166-167
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• 2015

The purpose of this study is to examine the effect on drying shrinkage of self-healing epoxy-modified mortars(EPMMs) using expansive admixtures. The EPMMs are prepared with polymer-binder ratios of 0 and 10%, and tested for drying shrinkage and pore structure analysis. As a result, regardless of the expansion and swelling agent content, the drying shrinkage of the EPMMs is remarkably decreased than that of unmodified mortars. Also, the pore size distribution of the EPMMs is moved to smaller size in comparison with unmodified mortars. In this study, the EPMM with expansive agent 7.5% and swelling agent 2.5% is recommended as a optimal mix proportion for reduction of drying shrinkage.