• Elastomers and Composites
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• 제57권4호
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• pp.197-204
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• 2022

Recently, the demand has increased for protective clothing materials capable of shielding the wearer from bullets, fragment bullets, knives, and swords. It is therefore necessary to develop light and soft protective clothing materials with excellent wearability and mobility. To this end, research is being conducted on hybrid design methods for various highly functional materials, such as carbon nanotube (CNT) sheets, which are well known for their low weight and excellent strength. In this study, a hybrid protective material using CNT sheets was developed and its performance was evaluated. The material design incorporated a bonding method that used a binder for interlayer combination between the CNT sheets. Four types of binders were selected according to their characteristics and impregnated within CNT sheets, followed by further combination with aramid fabric to produce the hybrid protective material. After applying the binder, the tensile strength increased significantly, especially with the phenoxy binder, which has rigid characteristics. However, as the molecular weight of the phenoxy binder increased, the adhesive force and strength decreased. On the other hand, when a 25% lightweight-design and high-molecular-weight phenoxy binder were applied, the backface signature (BFS) decreased by 6.2 mm. When the CNT sheet was placed in the middle of the aramid fabric, the BFS was the lowest. In a stab resistance test, the penetration depth was the largest when the CNT sheet was in the middle layer. As the binder was applied, the stab resistance improvement against the P1 blade was most effective.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.739-744
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• 2001

In this study, experimental research was carried out to develop protective finishing, coating materials and new hybrid technique for deteriorating prevention and high durability in concrete structures. It had sufficiently recommended performance for the protective finishing method of concrete structures through testings. This is more progressive double membrane method than single membrane type designed by conventional method. It was found that this hybrid construction method had very excellent performance to improve the durability of existing concrete structures and attain the beauty of concrete structures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술대회 논문집
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• pp.43-43
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• 2010

we have investigated the field emission characteristics of the CNT/TEOS hybrid thin films fabricated by a spray method. It is found that the CNT/TEOS hybrid emitters show high current density, low turn on field, and long-term emission stability compared to the CNT emitters. These efficient field emission characteristics of the CNT/TEOS hybrid emitters are attributed to the TEOS sol, acting as a protection layer of nanotube emitter by surrounding the nanotube tip as well as a binder material to enhance the adhesion of nanotube emitters to the substrate. Therefore, the CNT/TEOS hybrid emitters could be utilized as an alternative for the efficient and reliable field emitters.

• Composites Research
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• 제22권6호
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• pp.52-62
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• 2009

본 논문은 최적의 방호력과 편의성, 착용감을 갖춘 지뢰 탐지 및 지뢰 제거용 방호복의 국내 기술현황을 분석, 정리한 내용이다. 경량방호 소재는 고강도 직물 및 부직포 소재의 적절한 적층 배열 구조로 구성되어 있어 전체적인 방호복의 중량과 두께를 줄임으로써 착용감을 향상시켜야 한다. 한편 방호복은 인체 부위별 치명상의 정도에 따라 방호성능을 보강하도록 구성함으로써 최대한의 방호성능을 갖추면서 활동성 및 착용감을 향상시켜야 한다. 특히 디자인에 있어서 탈착 및 부착이 용이하고, 부상 시 환자를 움직이지 않고도 인체로부터 방호복을 분리해 낼 수 있도록 고안하여야 한다. 이와 함께 고강도/초경량 하이브리드 방탄 재료 기술 현황에 관하여서도 간략히 기술하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.509-514
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• 2001

The Fibre-optic Bragg grating (FBG) sensor is broadly accepted as a structural health monitoring device for Fibre reinforced plastic (FRP) materials by either embedding into or bonding onto the structures. The accuracy of the strain measured by using the FBG sensor is highly dependent on the bonding characteristics among the bare optical fibre, protective coating, adhesive layer and host material. In general, the signal extracted from the embedded FBG sensor should reflect the straining condition of the host structure. This paper presents a theoretical model to evaluate the differential strains between the bare fibre and host material with different adhesive thickness and modulus of the protective coating of the embedded FBG sensor.

• 한국안전학회지
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• 제34권6호
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• pp.1-6
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• 2019

Carbon fiber has excellent specific strength, corrosion resistance and heat resistance. And p-Aramid fiber has high toughness and heat resistance and high elasticity, and is used in various fields such as industrial protective materials, bulletproof helmets and vests, as well as industrial fields. However, carbon fiber is relatively expensive, and is susceptible to brittle fracture behavior due to its low fracture strain. On the other hand, the aramid fiber tends to decrease in elastic modulus and strength when applied to the epoxy matrix, but it is inexpensive and has higher elongation and fracture toughness than carbon fiber. Thus the twill hybrid carbonaramid fiber reinforced composite laminate composite was investigated for a delamination fracture toughness under Mode I loading by 2 kinds of MBT and MCC deduction. The specimen was fabricated with 20 hybrid fabric plies. The initial crack was made by inserting the teflon tape in the center plane with a₀/W=0.5 length. The results show that SERR(Strain Energy Release Rate) as the critical and stable delamination fracture toughness were 0.09 kJ/㎡, 0.386 kJ/㎡ by MBT deduction, and 0.192 kJ/㎡, 0.67 kJ/㎡ by MCC deduction, respectively.

• 멤브레인
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• 제30권1호
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• pp.30-37
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• 2020

리튬 덴드라이트의 효과적인 억제를 위해 유/무기 복합체를 리튬메탈 전극의 보호층으로 사용하였다. 유기물로는 PVDF-HFP가 사용되었으며 무기물로는 TiO₂가 사용되었다. 유기물로 사용된 PVDF-HFP는 높은 유연성을 가지는 고분자로서 무기물의 matrix 역할을 하며, 무기물로 사용된 TiO₂ 나노입자는 보호막의 기계적 강도와 이온전도성을 향상시켜주는 역할을 하였다. 합성된 보호막은 SEM, AFM, XRD를 통하여 PVDF-HFP matrix에 TiO₂가 잘 분산되어 있는 형태인 것을 확인할 수 있었다. 또한 전기화학적 분석 결과, 향상된 기계적 물성과 이온전도성으로 인해 polymer-inorganic composite은 비교 샘플(untreated 와 PVDF-HFP 보호층) 대비 100번째 사이클까지 80%의 높은 쿨롱 효율 및 20 mV 미만의 낮은 과전압을 나타내었다.

• 한국재료학회지
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• 제28권11호
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• pp.646-652
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• 2018

During a long-term operation of polymer electrolyte membrane fuel cells(PEMFCs), the fuel cell performance may degrade due to severe agglomeration and dissolution of metal nanoparticles in the cathode. To enhance the electrochemical durability of metal catalysts and to prevent the particle agglomeration in PEMFC operation, this paper proposes a hybrid catalyst structure composed of PtCo alloy nanoparticles encapsulated by porous carbon layers. In the hybrid catalyst structure, the dissolution and migration of PtCo nanoparticles can be effectively prevented by protective carbon shells. In addition, $O_2$ can properly penetrate the porous carbon layers and react on the active Pt surface, which ensures high catalytic activity for the oxygen reduction reaction. Although the hybrid catalyst has a much smaller active surface area due to the carbon encapsulation compared to a commercial Pt catalyst without a carbon layer, it has a much higher specific activity and significantly improved durability than the Pt catalyst. Therefore, it is expected that the designed hybrid catalyst concept will provide an interesting strategy for development of high-performance fuel cell catalysts.

• 한국해양공학회지
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• 제25권1호
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• pp.32-38
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• 2011

Galvanized steel has gone through a chemical process to keep it from corroding. The steel gets coated in layers of zinc because rust will not attack this protective metal. For countless outdoor, marine, or industrial applications, galvanized steel is an essential fabrication component. The reduction of the corrosion rate of zinc is an important topic. In the past, a very popular way to reduce the corrosion rate of zinc was to use chemical conversion layers based on $Cr^{+6}$. However, a significant problem that has arisen is that the use of chromium salts is now restricted because of environmental protection legislation. Therefore, it is very important to develop new zinc surface treatments that are environmentally friendly to improve the corrosion resistance of zinc and adhesion with a final organic protective layer. In this study, a Urethane solution (only Urethane 20 wt.%; S-700) and an organic/inorganic solution with Si (Si polysilicate 10 wt.% + Urethane 10 wt.%; LRO-317) are used. Based on the salt spray test of 72 h, S-700 and LRO-317 had a superior effect for the corrosion resistance on EGI and HDGI, respectively.

• 한국해양공학회지
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• 제24권5호
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• pp.60-66
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• 2010

Zinc has a number of characteristics that make it well suited for use as a coating to protecting iron and steel products from corrosion. Its excellent corrosion resistance in most environments accounts for its successful use as a protective coating on a variety of products and in many exposure conditions. The excellent field performance of zinc coatings results from their ability to form dense, adherent films that corrode at a rate that ranges from 1% to 10% of the corrosion rate of ferrous materials, depending on the environment. Recently, EU RoHS and EU ELV prohibited the use of materials that adversely affect the environment, such as Pb, Hg, Cd, and $Cr^{+6}$. In this study, environmentally-friendly, Cr-free solutions (epoxy solution, acrylic solution, and urethane solution S-700) and organic/inorganic solution with Si; LRO-317) were used to evaluate the corrosion resistance of zinc-coated steel subjected to a saltwater spray for 72 hours. The coating of urethane solution (S-700) was best among the three kinds of solution with heat treatment during five minutes at $190^{\circ}F$. Test specimens with S-700 and LRO-317 coating were heat treated in a drying oven at 170, 180, 190, 200, and $210^{\circ}C$ for five minutes. The results show that the optimum corrosion resistance was $190^{\circ}C$ in EGI and $170^{\circ}C$ in HDGI, respectively.