• Composites Research
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• v.13 no.3
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• pp.1-8
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• 2000

Excellent environmental durability and handy installation procedure as well as high specific strength and stiffness have introduced fiber-reinforced polymeric composite materials into the civil and architectural engineering field. This study presents the considerably enhanced strength characteristics of the mortal beams by being reinforced with epoxy-bonded carbon fiber sheets(CFS). Three point bending and Charpy impact tests were performed on both of bare and reinforced mortar specimens. The influences of length, and the number of reinforcing plies were investigated. Strength reduction due to pre-existent notch was lessened dramatically. The acoustic emission(AE) measurement revealed the progressive damage process in reinforced specimens.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.432-434
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• 2005

• Environmental Engineering Research
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• v.13 no.1
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• pp.19-27
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• 2008

Simultaneous removal of ternary gases of $NH_3$, $H_2S$ and toluene in a contaminated air stream was investigated over 180 days in a biofilter. A commercially available inorganic/polymeric composite chip with a large void volume (bed porosity > 0.80) was used as a microbial support. Multiple microorganisms including Nitrosomonas and Nitrobactor for nitrogen removal, Thiobacillus thioparus (ATCC 23645) for $H_2S$ removal and Pseudomonas aeruginosa (ATCC 15692), Pseudomonas putida (ATCC 17484) and Pseudomonas putida (ATCC 23973) for toluene removal were used simultaneously. The empty bed residence time (EBRT) ranged from 60 - 120 seconds and the inlet feed concentration was $0.0325\;g/m^3-0.0651\;g/m^3$ for $NH_3$, $0.0636\;g/m^3-0.141\;g/m^3$ for $H_2S$, and $0.0918\;g/m^3-0.383\;g/m^3$ for toluene, respectively. The observed removal efficiency was 2% - 98% for $NH_3$, 2% - 100% for $H^2S$, and 2% - 80% for toluene, respectively. Maximum elimination capacity was about $2.7\;g/m^3$/hr for $NH_3$, > $6.4\;g/m^3$/hr for $H_2S$ and $4.0\;g/m^3$/hr for toluene, respectively. The inorganic/polymeric composite carrier required 40 - 80 days of wetting time for biofilm formation due to the hydrophobic nature of the carrier. Once the surface of the carrier was completely wetted, the microbial activity became stable. During the long-term operation, pressure drop was negligible because the void volume of the carrier was two times higher than the conventional packing materials.

• Elastomers and Composites
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• v.57 no.2
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• pp.48-54
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• 2022

A polymeric adhesion promoter was synthesized to improve the adhesive strength of the Ni lead frame/epoxy composite. Poly(itaconic acid-co-acrylamide) (IAcAAM) was prepared by copolymerizing itaconic acid and acrylamide. We compared the adhesive strength between the Ni lead frame and epoxy composite according to the molecular weight of IAcAAM. The molecular weight of IAcAAM was controlled using an initiator, which made it possible to use IAcAAM in the epoxy molding compound (EMC) manufacturing process by modulating the melting temperature. The adhesive strength of Ni lead frame/epoxy composite increased with the addition of IAcAAM to the epoxy composite. In addition, as the molecular weight of IAcAAM increased, the adhesive strength of the Ni lead frame/epoxy composite slightly increased. We confirmed that IAcAAM with an appropriate molecular weight can be used in the EMC manufacturing process and increase the adhesive strength of the Ni lead frame/epoxy composite.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.123-132
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• 1995

During compression molding of fiber-reinforced polymeric composites, microstructural changes such as the fiber-matrix separation and the fiber orientation are occurred by the flow of composite materials. Since the nonhomogeneity and anisotropy of composites are caused by the separation and orientation of fibers. On the other hand, the separation and the orientation of fibers are inseparably related to each other. In this paper the degree of nonhomogeneity which is a measure of the separation is obtained using one-dimensional rectangular shaped part compression molding. And the orientation function is measured by the image processing using soft X-rayed photograph and image scanner. We study effects of the mold temperature on the degree of nonhomogeneity and the orientation function.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.588-591
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• 2002

Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. The effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on poly(vinyl ether of ethyleneglycol : PVEEG) have been studied for investigating mechanical and electric property of polymer composites applications.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.85-87
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• 2004

Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. New polymeric hydrogels based on vinyl ethers have been synthesized by the ${\gamma}$-initiated polymerization method. In this paper, we have studied the effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on poly (vinyl ether of ethyleneglycol: PVEEG).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.855-859
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• 2005

Carbon fiber polymeric composites have been widely used in bearing materials under high pressure without oil-lubrication due to their self-lubricating characteristics. However, the severe wear of carbon composite surface occurs due to the generation of wear debris when the pressure applied on the composite surface is higher than the critical value of composite surface. In this work, in order to remove wear debris continuously during sliding operation, composite specimens with many micro-grooves on their sliding surfaces were devised. To investigate the effect of wear debris on the tribological behavior of carbon/epoxy composites, dry sliding tests were performed with respect to applied pressure using the composite specimens with and without micro-grooves. From the measurement of friction coefficients and wear rates, a model for the effect of wear debris on the friction and wear of composites was proposed.

• Archives of Pharmacal Research
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• v.26 no.11
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• pp.973-978
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• 2003

A polymeric film composed of Carbopol, Poloxamer and hydroxypropyl methylcellulose was prepared to develop a buccal patch and the effects of composition of the film on adhesion time, swelling ratio, and dissolution of the film were studied. The effects of plasticizers or penetration enhancers on the release of triamcinolone acetonide (TAA) were also studied. The hydrogen bonding between Carbopol and Poloxamer played important role in reducing swelling ratio and dissolution rate of polymer film and increasing adhesion time. The swelling ratio of the composite film was significantly reduced and the adhesion time was increased when compared with Carbopol film. As the ratio of Poloxamer to hydroxypropyl methylcellulose increased from 0/66 to 33/33, the release rate of TAA decreased. However, no further significant decrease of release rate was observed beyond the ratio of 33/33. The release rate of TAA in the polymeric film containing polyethylene glycol 400, a plasticizer, showed the highest release rate followed by triethyl citrate, and castor oil. The release rate of TAA from the polymeric film containing permeation enhancers was slower than that from the control without enhancers. Therefore, these observations indicated that a preparation of a buccal patch is feasible with the polymeric film composed of Cabopol, Poloxamer and hydropropyl methylcellulose.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.403-408
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• 2006

To enhance the dental properties of polymeric dental restorative composite activated by visible-light, the surface of hydrophilic silica nanoparticle was hydrophobically treated using $\gamma$-methacryloxypropyltrimethoxysilane ($\gamma$-MPS) coupling agent. Structural properties and dispersity of silica in the composite was compared with the hydrophobicity of silica. Polymerization characteristic of the composite was also evaluated. Degree of hydrophobicity of silica nanoparticle was considerably improved with an increase of $\gamma$-MPS upto 40 wt% and converged asymptotically. Additionally, with an increase of the hydrophobicity of silica nanoparticle, the dispersity of silica was improved and the residual monomer in the composite was not detected from nuclear magnetic resonance experiment which indicated superior polymerization behavior.