• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.313-319
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• 2012

In this work, the electroplating of copper was introduced on PAN-based carbon fibers for the enhancement of mechanical interfacial strength of carbon fibers-reinforced composites. The surface properties of carbon fibers were determined by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and contact angle measurements. Its mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS) and critical stress intensity factor ($K_{IC}$). From the results, it was found that the mechanical interfacial properties of Cu-plated carbon fibers-reinforced composites (Cu-CFRPs) enhanced with increasing the Cu plating time, Cu content and COOH group up to Cu-CFRP-30. However, the mechanical interfacial properties of the Cu-CFRPs decreased dramatically in the excessively Cu-plated CFRPs sample. In conclusion, the presence of Cu particles on carbon fiber surfaces can be a key factor to determine the mechanical interfacial properties of the Cu-CFRPs, but the excessive Cu content can lead the failure due to the interfacial separation between fibers and matrices in this system.

• Polymer(Korea)
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• v.31 no.3
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• pp.221-227
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• 2007

The mechanical properties and morphologies of lyocell and its blend we compared. Poly (vinyl alcohol) (PVA) was used as a filler in blends with lyocell produced through solution blending. The variations of their properties with polymer matrix filler content are discussed. The ultimate tensile strength of the PVA/lyocell blend is highest for a blend lyocell content of 30 wt%, and decreases as the lyocell content is increased up to 40 wt%. The variations in the initial moduli of the blends with filler content are similar. Lyocell and its blended hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium-mica ($C_{12}PPh$-Mica) as the organoclay. The variations of the mechanical tensile properties of the hybrids with the organoclay content were examined. These properties were found to be optimal for an organoclay content of up to 5 wt%. However, the mechanical tensile properties of the PVA/Lyocell (w/w=30/70) blended hybrid films were found to decrease linearly with increases in organoclay content from 1 to 5 wt%.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.2
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• pp.137-143
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• 2020

The CM247LC, a Ni-based superalloy material used for gas turbine hot gas path parts, is casted using directionally solidified technology to analyze the mechanical properties and microstructures through HIP (Hot Isostatic Pressing) and post-heat treatment, and to derive optimal HIP treatment conditions. The CM247LC material is being researched in various ways as an alternative material for prototyping gas turbine blades. In particular, the blade rotating part is exposed and operated in a high temperature and high-pressure environment, and when damaged, it may cause huge economic losses. Therefore, in order to use the CM247LC material as prototyping materials for gas turbine blades, the reliability of the microstructure and mechanical properties must be verified. In this study, after casting rod test specimens using CM247LC material by directionally solidified technology, after that the specimens were performed by HIP treatment and post-heat treatment to test two HIP conditions designed by KEPCO to derive the possibility of prototyping of CM247LC material and optimization of HIP treatment conditions. Additionally, the properties of CM247LC material were compared to the GTD111DS material using for 1,300℃ class gas turbine blades.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.2
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• pp.45-51
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• 2020

As flexible electronics will be used under high temperature and high humidity with repeated bending deformations, the effects of environmental condition and repeated mechanical deformations are considered simultaneously to achieve long-term reliability. In this study, the mechanical reliability of metal electrodes (Al, Ag, Cu) deposited on flexible polymer substrate is investigated under 4 different conditions: with and without repeated mechanical deformations and normal environmental or high temperature and high humidity conditions (85℃/85%). The mechanical failure does not occur in all the metal electrodes without mechanical deformation even under high temperature and high humidity conditions. The electrical resistance of metal electrode increased about 400% to 600% after 100,000 bending cycles under normal condition. For high temperature and high humidity condition, the electrical resistance of Al and Ag increased similarly. However, the resistance of Cu during bending fatigue test under high temperature and high humidity condition increased over 90000% because of the combined effect of corrosion and mechanical fatigue. This study can give a helpful information for designing electrode materials with high mechanical reliability under high temperature and high humidity.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.438-442
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• 2011

Mechanical and morphological properties of poly(acrylonitrile-butadiene-styrene) (ABS) and poly(lactic acid) (PLA) blends containing compatibilizers were investigated. Poly(styrene-acrylonitrile)-g-maleic anhydride) (SAN-g-MAH), poly(ethylene-co-octene) rubber-maleic anhydride (EOR-MAH) and poly(ethylene-co-glycidyl methacrylate) (EGMA) were used as compatibilizers. Mechanical properties such as tensile, flexural and impact strengths of ABS/PLA (80/20, wt%) blends were found to be increased when the SAN-g-MAH, EOR-MAH and EGMA were used. The maximum values for mechanical properties of the ABS/PLA (80/20) blend were observed when SAN-g-MAH was used as a compatibilizer at the concentration of 3 phr. From morphological studies of the ABS/PLA (80/20) blends, PLA droplet size was decreased by the addition of the compatibilizers used in this study. From the results of mechanical and morphological properties of the ABS/PLA (80/20) blends, SAN-g-MAH (3 phr) was found to be the most effective compatibilizer among the compatibilizers used in this study.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.517-523
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• 2015

As the aluminum (Al) metallization process was replaced with copper (Cu), the damascene process was introduced, which required the planarization step to eliminate over-deposited Cu with Chemical Mechanical Polishing (CMP) process. In this study, the verification of the corrosion inhibitors, one of the Cu CMP slurry components, was conducted to find out the tendency regarding the carboxyl and amino functional group in neutral environment. Through the results of etch rate, removal rate, and chemical ability of corrosion inhibitors based on 1H-1,2,4-triazole as the base-corrosion inhibitor, while the amine functional group presents high Cu etching ability, carboxyl functional group shows lower Cu etching ability than base-corrosion inhibitor which means that it increases passivation effect by making strong passivation layer. It implies that the corrosion inhibitor with amine functional group was proper to apply for 1st Cu CMP slurry owing to the high etch rate and with carboxyl functional group was favorable for the 2nd Cu CMP slurry due to the high Cu removal rate/dissolution rate ratio.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.68-74
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• 2017

Epoxy resins are widely used in various fields due to their excellent thermal, mechanical and chemical properties. In order to improve the mechanical properties of the epoxy composition after curing, various materials are mixed in the epoxy resin. Among the nano materials, CNT is the most widely used. However, CNT has limitations in terms of manufacturing process and manufacturing cost. Therefore, there is a growing interest in naturally occurring HNTs having similar structure to that of CNT. In this study, the thermal and mechanical properties of epoxy compositions containing HNTs treated with two types of silane compounds were investigated. The mechanical properties of silane-treated HNT were measured by using a universal testing machine. The differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA) were used to measure thermal properties. As a result of the above tests, when the HNT was surface-treated with aminosilane, the tensile strength of the epoxy composition containing the HNT was higher than that of the epoxy composition containing epoxy silane treated HNT. The linear thermal expansion coefficients (CTE) obtained from the thermomechanical analysis of the two epoxy compositions for the comparison of dimensional stability showed that the HNT composition treated with aminosilane showed a lower value of CTE than that of epoxy composition including the pristine HNT.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.12
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• pp.1037-1046
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• 2016

In this study, to enhance the electrical insulation of composite specimens in addition to the improved mechanical properties, the epoxy composite were reinforced with carbon nanotubes and silica particles. Tensile strength, Young's modulus, dynamic mechanical behavior, and electrical resistivity of the specimens were measured with varied contents of the two fillers. The mechanical and electrical properties were discussed, and the experimental results related to the mechanical properties of the specimens were compared with those from several micromechanics models. The hybrid composites specimens with 0.6 wt％ of carbon nanotubes and 50 wt％ of silica particles showed improved mechanical properties, with increase in tensile strength and Young's modulus up to 11％ and 35％, respectively, with respect to those of the baseline specimen. The electrical conductivity of the composite specimens with carbon nanotubes filler also improved. Further, the electrical insulation of the hybrid composites specimens with the two fillers improved in addition to the improvement in mechanical properties.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.135-141
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• 2020

The silica aerogels with benzene-bridged were designed to have uniform network structure, ordered pore structure, improved mechanical properties and excellent textural properties. Adding organic to enhance the mechanical properties of silica aerogels is a common method, but textural properties of aerogels with organic are reduced due to the organic-inorganic phase separation. In this paper, we use a simple and low-cost method to increase mechanical properties while maintaining textural properties of SiO2 aerogels. Two types of benzene-bridged precursors were prepared to study the effect of the number of hydroxyl band on the textural and mechanical properties. The porous silica aerogel was prepared by a simple, cost effective and pollution-free sol-gel method. This method does not require additional silylating reagents. The benzene-bridged silica aerogel samples prepared had excellent textural properties, high specific surface area (1,326 ㎡/g), porous structure and hydrophobicity (>140°). The mechanical strength of 2T4 is more than 5 times that of pure silica aerogel.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.609-615
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• 2021

The aim of the present study was to investigate the mechanical properties of melt-injected poly lactic acid (PLA) composites with β-tricalcium phosphate (β-TCP). The PLA mixed with calcined PLA/β-TCP powder to be contents of 0, 10, 30, 50 wt%, respectively, was dissolved in chloroform solvent under stirring for 24 h. Then the liquid mixtures were dropped into ethanol to extract solvent. After drying, the well-dispersed PLA/β-TCP composites were granulated and melt-injected to prepare specimens for various mechanical testing. PLA/β-TCP induced the precipitation of an apatite bone-mineral phase on the surface after immersion in a human simulated body fluid (SBF) for 90 days, showing in bioactivity. Mean various mechanical properties PLA/β-TCP composite were increased up to 10-30 wt% with significantly in part and composite were decreased 50 wt% of showing in mechanical properties. In conclusion, Over 30 wt% addition of β-TCP to PLA may be not advisable to improve the mechanical properties of melt-injected polymeric composites. Results indicated that β-TCP can be used considered as potential reinforcing agent for increasing mechanical properties for PLA. Therefore, it was suggest that the additional effects of β-TCP and research on a wide range of substances.