• Journal of the Korean Applied Science and Technology
• /
• v.33 no.4
• /
• pp.615-626
• /
• 2016

In the paper, mild solvent soluble alkyl group modified epoxy resins were prepared via a three-step method; (1) the condensation reaction of dodecyl phenol (DP) and formaldehyde, (2) the crosslinking reaction of dodecyl phnol novolac compound (DPC) and bisphenol A diglycidyl ether, (3) the dodecyl phenol novolac epoxy resins containing fatty acid (DPFA) was prepared by introducing fatty acid to DPC. Equivalent ratios of DP and formaldehyde were 1.25~1.333/1.0. Equivalent ratio of DPC and bisphenol A diglycidyl ether (YD-128) was 1.0/2.0. Reactivity, viscosity, molecular weight, solvent solubility, and physical properties of DPFA were investigated. The result show that as the number of aromatic ring of DPFA increased, viscosity increased and solvent solubility improved. When we test the properties of coatings by blending the synthesized DPFA with a white pigment, DPFAC-5 using triphenylphosphine (TPP) as a ring-open catalyst showed optical performance for drying time, adhesion, hardness, impact resistance, acid resistance and storage stability.

• Elastomers and Composites
• /
• v.45 no.1
• /
• pp.12-16
• /
• 2010

In this work, the effect of hydrophobic treated silica on the water absorption, thermal stabilities, and mechanical properties of the epoxy nanocomposites were investigated as a function of the silica content. As filler, fumed silica treated by dimethyldichlorosilane was used. It was found that the silica was well dispersed in the epoxy resins by the melt-mixing method with the addition of a silane coupling agent. The water absorption of the nanocomposites decreased with an increase of the silica content due to the effect of hydrophobic treated silica. The thermal properties, such as thermal degradation temperature, glass transition temperature ($T_g$), and coefficient of thermal expansion (CTE), of the nanocomposites were improved by the addition of silica. Furthermore, the mechanical properties of the nanocomposites, that is, the tensile strength and modulus, were enhanced with increasing silica content. This was attributed to the physically strong interaction between silica and epoxy resins.

• Journal of Conservation Science
• /
• v.27 no.4
• /
• pp.431-440
• /
• 2011

The thermal expansion coefficient of epoxy/inorganic additives composites was controlled by changing the amount of the inorganic additives such as talc and fused silica. The epoxy resin comprises hydrogenated bisphenol A (HBA)-based epoxide, difunctional polyglycidyl epoxide (DPE) as a diluent and isophorone-diamine (IPDA) as a crosslinking agent, which was subsequently mixed with inorganic additives (talc and fused silica). The thermal expansion coefficient was decreased by increasing amount of inorganic additives, nearly to fresh granite. Fused silica was more effective than talc in lowering the thermal expansion coefficient. Additionally, lexural and tensile strengths of the composites were getting lower and higher with the amount of the inorganic fillers, respectively. It was thus concluded that an epoxy composite containing inorganic fillers was developed to show much lower thermal expansion coefficient, similar to fresh granite, than the neat epoxy resin, and also proper mechanical strengths for applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.6 no.3
• /
• pp.51-63
• /
• 1999

The effects of high filler loading technique on the reliability of epoxy molding compound (EMC) as a microelectronic encapsulant was investigated. The method of high filler loading was established by the improvement of maximum packing fraction using the simplified packing model proposed by Ouchiyama, et al. With the maximum packing fraction of filler, the viscosity of EMC wart lowered and the flowability was improved. As the amount of filler in EMC increased, several properties such as internal stress and moisture absorption were improved. However, the adhesive strength with the alloy 42 leadframe decreased when the filler content was beyond the critical value. It was found that the appropriate content of filler was important to improve the reilability of EMC, and the optimum filler combination should be selected to obtain high reliable EMC filled with high volume fraction of filler.

• Applied Chemistry for Engineering
• /
• v.5 no.6
• /
• pp.1030-1035
• /
• 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 the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.2
• /
• pp.154-160
• /
• 2009

This paper shows a basic data of the surface discharge characteristics for epoxy resin in Dry-Air as being focused on environmentally friendly insulating Gas. Used electrodes are needle to plane, sphere to plane and KS M3015 electrodes. With the changing electrodes in same condition, we can obtain different creeping lengths, surface discharge voltages and surface dielectric strengths, respectively. Surface dielectric strengths of Needle to plane electrodes are more higher than the others. Moreover, it is considered that the surface discharge characteristics with variation of epoxy resin thickness and diameter. Surface discharge voltage increases as the thickness and the diameter of epoxy resin.

• The Korean Journal of Rheology
• /
• v.11 no.2
• /
• pp.135-142
• /
• 1999

The effects of 1 wt.% N-benzylpyrazinium hexafluoroantimonate (BPH) as a thermal latent initiator and blend compositions composed of 0, 5, 10, 20 and 40 wt.% of phenol-novolac resin to epoxy resin were investigated in terms of cure kinetics, thermal stabilities and rheological properties. Thermal latent properties of BPH were measured from the conversion as a function of reaction temperature on a dynamic DSC. This cationic BPH system turned out to be an effective thermal latent initiator in the epoxy-phenol curing system. And the increase of phenol-novolac resin concentration led to the decrease in the latent temperature and to the increase of cure activation energy ($E_a$) of the blend system. The thermal stability and activation energy ($E_t$) for decomposition, gel-time and activation energy ($E_c$) for cross-linking from rheometer increased within the composition range of 20~40 wt.% of phenol-novolac resin. This implies that the three-dimensional cross-linking may take place among hydroxyl group within phenol resin, epoxide ring within epoxy resin and BPH.

• Journal of the Korean Society for Railway
• /
• v.12 no.6
• /
• pp.1059-1066
• /
• 2009

Recently, the amount of thermosetting plastic wastes has increased with the production of reinforced plastic composites and causes serious environmental problems. The epoxy resins, one of the versatile thermosetting plastics with excellent properties, cannot be melted down and remolded as what is done in the thermoplastic industry. In this research, a series of experiments that decompose epoxy resin and recover carbon fibers from carbon fiber reinforced epoxy composites applied to railway vehicles was performed. We experimentally examined various decomposition processes and compared their decomposition efficiencies and mechanical property of recovered carbon fibers. For the prevention of tangle of recovered carbon fibers, each composites specimen was fixed with a Teflon supporter and no mechanical mixing was applied. Decomposition products were analyzed by scanning electron microscope (SEM), gas chromatography mass spectrometer (GC-MS), and universal testing machine (UTM). Carbon fibers could be completely recovered from decomposition process using nitric acid aqueous solution, liquid-phase thermal cracking and pyrolysis. The tensile strength losses of the recovered carbon fibers were less than 4%.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.5 no.2
• /
• pp.77-83
• /
• 1991

In this study the investigation were carried out on short-term breakdown characteristics of the compound material dependent on change of filler quantity, ambient temperature(room temperature~[$190[^{\circ}C$]) and kinds of voltage sources for the compound materials of Bisphenol- A epoxy resins filled with $SiO_2$ particles. As the results, obtained the dielectric breakdown strength generally decrease as increasing the quantity of filler and the distance, spacing of each's particles, decrease as increasing the quantity of filler, when the distance is less than [$7.5\mu\textrm{m}$], dielectric breakdown strength is nearly constant. In the case on AC voltage dielectric strength of filled epoxy resins is stronger than nonfilled epoxy resins on temperature region more than $130[^{\circ}C$].

• Journal of the Microelectronics and Packaging Society
• /
• v.17 no.1
• /
• pp.41-46
• /
• 2010

The interfacial adhesion strengths between screen-printed Ag film and epoxy resin-coated polyimide were evaluated by $180^{\circ}$ peel test method. Measured peel strength value was initially around $164.0{\pm}24.4J/m^2$, while the heat treatment during 24h at $120^{\circ}C$ increase peel strength up to $220.8{\pm}19.2J/m^2$. $85^{\circ}C/85%$ RH temperature/humidity treatment decrease peel strength to $84.1{\pm}50.8J/m^2$, which seems to be attributed to hydrolysis bonding reaction mechanism between metal and adhesive epoxy resin coating layer.