• Proceedings of the KSME Conference
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• 2001.11a
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• pp.228-233
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• 2001

It is well known that composite laminates are easily damaged by low velocity impact. The damage of composite laminates subjected to impact loading are occurred matrix cracking, delamination, and fiber breakage. The damage of matrix cracking and delamination are reduced suddenly the compressive strength after impact. This study is to evaluate impact characteristics and the relationship between impact force and inside damage of composite laminates by low velocity impact loading. UT C-scan is used to determine impact damage areas by impact loading.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.31-34
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• 2005

For the damage tolerance improvement of conventional laminated composites, stitching process has been utilized for providing through-thickness reinforcements. 2D prefonl1S were stacked with S-2 glass plain weave, and 3D preforms were fabricated using the stitching process. For the matrix system, epoxy and phenol resins were considered. To examine the damage resistance performance the low velocity drop weight impact test has been carried out, and the impact damage was examined by scanning image. CAI (Compressive After Ih1paet) tests were also conducted to evaluate residual compressive strength. Compared with 2D epoxy composites, 2D phenol composites showed drastic reduction in the compressive strength prior to impact because of the higher contents of voids. The damage area of 2D phenol composites were also larger than that of 2D epoxy composites. However, by introducing the stitching, the damage area of 3D phenol composites was reduced by 60%, while the CAI strength improvement was negligible.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.457-460
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• 2002

현재 건축단열재, 흡음재, 바닥재로 사용되는 panel 성형, 제작하기 위해 다종의 유기고분자 matrix가 사용되고 있으며 polyurethane, vinyl acetate, urea-formaldehyde resin 또는 melamine-formaldehyde, phenol-form aldehyde resin 등을 사용하고 있으나 이러한 고분자 matrix를 사용한 건축용 panel의 경우 화재시 유독 gas와 더불어 급격한 화재전파의 매개체로 사용될 수 있어 난연제 첨가로 이러한 현상을 억제하고 있다.(중략)

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.77-81
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• 2006

The commercially available Amberlite XAD-2 and XAD-4 resins were modified with macrocyclic protoporphyrin IX (PPIX) or tetrakis(p-carboxyphenyl) porphyrin (TCPP) to enhance the adsorption capacity for phenol and chlorophenols. The chemically modified polymeric adsorbents (XAD-2+PPIX, XAD-2+TCPP, XAD-4+PPIX, and XAD-4+TCPP) were applied to the solid phase extraction as an adsorbent material for the preconcentration of phenol and chlorophenols in environmental waters. Generally, the synthesized adsorbents showed higher recoveries than underivatized adsorbents, XAD-2 and XAD-4, without matrix interferences. Especially, XAD-4+PPIX showed more than 90% recoveries for all compounds used in this study including hydrophilic phenol. The major factor for the increase of the adsorption capacity was the increase of $\pi$-$\pi$ interaction between adsorbents and samples due to the introduction of the porphyrin molecule. However, the breakthrough volumes and recovery values of the XADs+TCPP columns were slightly decreased for the bulky chlorophenols such as TCP and PCP. Using molecular mechanics methods, the structures of TCPP and PPIX were compared with that of porphine, the parent molecule of porphyrin. Four bulky p-carboxyphenyl groups of TCPP were torsional each other, thus the molecular plane of TCPP were not on the same level. In conclusion, the decrease of breakthrough volumes and recovery values of XADs+TCPP columns for bulky phenols can be explained by the steric hindrance of the $\pi$-$\pi$ interaction between porphyrin plane and the phenols.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.89-92
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• 2002

Traditionally unidirectional laminated composite which are characterized by high specific stiffness and strength were used for structural application. But theses composites are highly susceptible to impact damage because of lower transverse tensile strength. The main failure modes of laminated composite are fiber breakage, matrix cracking and delamination for low velocity impact. The modified failure criterions are implemented to predict these failure modes with finite element analysis. Failure behavior of the woven fabric laminated composite which is used in forehead part of subway to lighten weigh has been studied. The new failure criterions are in good agreement with experimental results and can predict the failure behavior of the woven fabric composite plate subjected to low velocity impact more accurately.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.179-182
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• 2001

Impacter tester was build of to evaluate the characterization of non-flamable Glass/phenol laminate plates under the low velocity impact. The damage of composite laminates are matrix cracking, delamination, and fiber breakage for impact energy. In this study, this is to find impact properties of Glass/phenol in used in a forehead part of lighting subway. To determine impact damage characteristics which is made in a laminate, use the UT C-scan after- macrography. And then evaluated the reduction of strength in a rate of impact energy with CAI(Compression After Impact) test

• Journal of the Korean Society of Safety
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• v.12 no.1
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• pp.71-76
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• 1997

In this paper, it was described results of study on curing safety of molding meterial, about the variation of phenol resin contents, wood flour contents and moisture of wood flour, under the same condition. The experimental results are summarized as follows ; 1) When the curing temperature was high, the curing time was short in the case of 4～8wt% moisture of wood flour, but in the case of more than l2wt% moisture of wood flour, the curing time was long. 2) The curing time for curing temperature was more short when 6wt% moisture of wood flour than 4wt% moisture of wood flour. 3) The more wood flour content and moisture of wood flour content, the longer curing time and the more mineral filler content, the shorter curing time. 4) When the phenol resin content of main matrix increase, the curing time was short.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.93-96
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• 2002

Instrumented impact tests and compression-after-impact(CAI) tests have been used to evaluate the effect of temperature on the low-velocity impact characteristics of phenolic matrix composites reinforced with various woven glass fabric. Impact characteristics and damage area in laminates are evaluated by C-scan. It is shown that the extent of damage and residual compressive strength of the laminates vary with energy level and impact test temperature. The damage area increases with increasing impact energy and temperature. All these observations indicate reduced impact damage resistance and damage tolerance of the laminates at elevated temperature.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.301-305
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• 2009

The novel carbon coating process for interlayer of fiber reinforced ceramic composites between fiber and matrix was performed by carbonizing phenolic resin solution that coated on fiber surface in $N_2$ atmosphere at $600^{\circ}C$ to improve the strength and fracture toughness of CMC(ceramic matrix composite). 160 nm carbon layer was coated on fiber surface with 5 vol% of phenolic resin solution. Since the process temperature ($600^{\circ}C$) is lower than chemical vapor deposition($900{\sim}1000^{\circ}C$), the strength and toughness could be preserved. Furthermore the coating thickness uniformity was improved to 8% of deviation along the stacking sequence. Therefore, prevention from fiber degradation during coating process and controlling coating thickness uniformity along the preform depth were achieved by coating with phenolic resin carbonizing method.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.973-978
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• 1997

The toughness and morphology of epoxy resin based on diglycidyl ether of bisphenol A(DGEBA) cured with of tris (dimethylaminomethy]) phenol(DMP-30) and castor oil (CO) as a toughening modifier have been studied. Mixtures of CO and an epoxy resin showed a higher miscibility than the classical CTBN modified epoxy resin. The glass transition temperature($T_g$) was decreased with the CO content and the cure temperature. It is interpreted that the networks of epoxy matrix obtained at high temperature are apparently looser and more flexible due to the lower crosslinking density. The toughness was slightly increased with the CO content at $40^{\circ}C$ of curing temperature. The toughness increased with increasing the cure temperature and CO content.