• Elastomers and Composites
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• 제41권2호
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• pp.97-107
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• 2006

폐타이어와 폐수지 처리 문제를 해결하기 위한 방법으로 재생 폴리에틸렌 수지와 신재HDPE를 폐타이어 분말(GWTP)과 치합형 동방향 회전 이축 압출기(Fuly Intermeshing Co-rotating Twin Screw Extruder)를 이용하여 각 조성별로 용융 훈련하여 재생 PE/폐타이어 복합체를 제조하였다. 본 연구에서는 플라스틱 수지 (재생 PE, HDPE)와 폐타이어 분말의 혼합비를 $0\sim50$wt.%로 하였으며, ASTM에 의거하여 인장강도, 파단신율, 충격강도 등의 물성 변화를 확인하였다. 폐타이어 분말 함량이 증가할수록 인장강도가 감소하고 파단신율이 증가하였다. 한편 충격강도는 폐타이어 분말 함량이 30 wt.%일 때 최대이고, 함량이 증가할수록 충격 강도가 감소하는 경향을 나타내었다. 형태학적 고찰에서는 폐타이어 분말의 함량의 증가함에 따라 파단면이 거칠어지는 형상을 관찰하였다. 모세관점도계(Capillary Rheometer)를 이용하여 재생 PE/폐타이어 분말 복합체의 전단속도의 변화에 따른 용융전단점도의 변화와 연화점 (Ts) 등의 유변학적 성질을 분석한 결과, 폐타이어 분말 함량 증가에 따라 외부 응력에 대한 흐름 저항성을 증가시켜 용융점도가 상승하는 결과를 보였으며 측정된 전단율에서 전단 점도는 Power-law 거동을 보였다.

• 한국분말재료학회지
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• 제14권1호
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• pp.13-18
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• 2007

The mother Ni-W (1-5 wt.%) alloy billets for coated conductor substrate were fabricated by powder metallurgy process. The tensile test results for the sintered Ni-W rods showed the increase of mechanical strength and decrease of ductility with increasing W content due to the solid solution hardening. All the fracture surfaces of the tested specimens showed the typical ductile fracture mode of dimple rupture due to the local necking. The Ni-W alloy billets were made into tape by cold rolling. After the appropriate heat treatment for recrystallization, the brass texture formed by the cold rolling was converted to the complete cube texture. The in-plane and out of plane texture of the tapes estimated by x-ray pole figure were smaller than 9 degree and 7 degree, respectively. The effect of the W addition on the texture development seems not to be significant.

• 한국염색가공학회지
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• 제22권3호
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• pp.214-219
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• 2010

Polyethylene(PE) films were photocrosslinked by continuous UV irradiation. Benzophenone addition as low as 1wt% into the PE film increased the gel fraction up to 96%. The photocrosslinking was attributed to the recombination of PE radicals generated upon UV irradiation, which was enhanced by the hydrogen abstraction of the added benzophenone. Also the crossliked PE showed higher thermal stability and decreased crystallinity with increasing UV energy as shown by TGA, XRD and DSC analysis. It was also possible to fix 5.4% octadecane into PE by the photocrosslinking. The crosslinked PE film containing octadecane showed lower tensile strength and modulus coupled with higher extension compared to that without octadecane, which can be used as a new plasticizing method for the crosslinked PE film.

• 한국의류산업학회지
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• 제12권4호
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• pp.494-499
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• 2010

Knitted fabrics are very popular for their numerous advantages such as greater comfort, attractive garment appearance, better fit on the body, etc. In this study, we investigated the mechanical properties and abrasion property of warp knitted fabrics for footwear which treated with several softeners to improve abrasion resistance. The antistatic softener among the various softeners showed high improvement in abrasion resistance. Among the mechanical properties with treating conditions, WT (tensile energy), G (shear stiffness), B (bending rigidity) increased as treating timeincreased. But the other mechanical properties were little changed with treating concentration.

• Journal of Welding and Joining
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• 제30권4호
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• pp.49-54
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• 2012

The microstructure and mechanical properties of the high-strength low-alloy steel weld metals with a variation of nickel content were investigated. The weld metals with a variation of nickel content from 2.3 to 3.3 wt% were prepared using Gas Metal Arc Welding process. The amount of acicular ferrite decreased with increasing nickel content; this is accompanied with an increase in the region of bainite and martensite, hence the hardness and tensile strengths were increased with the increase in nickel content, whereas the impact energy was deteriorated.

• 폴리머
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• 제38권2호
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• pp.232-239
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• 2014

용액 삽입(solution intercalation) 방법을 이용하여 다양한 나노 필러들을 포함하는 poly(lactic acid)(PLA) 나노 복합체를 합성하였다. 유기화 반응 처리된 벤토나이트 점토(NSE), 옥타데실아민(ODA)을 산화 그래핀(GO)에 반응한 ODA-GO, 그리고 유기화 처리된 벤토나이트와 ODA-GO의 복합체인 NSE/ODA-GO 등이 PLA 복합체 필름을 얻기 위한 나노 필러로 각각 사용되었다. 3가지 나노 필러들은 0-10 wt%의 함량으로 사용되었고 PLA 복합체 필름들의 열적-기계적 성질, 모폴로지, 산소 투과도 결과들을 서로 비교하였다. 투과전자현미경을 통하여 얻은 결과에서 NSE/ODA-GO 복합체는 약간 뭉쳐있었지만, NSE나 ODA-GO 등의 필러들은 PLA 매트릭스에 분산이 매우 양호하였음을 알 수 있었다. PLA 복합체 합성을 위해 사용된 3가지 필러 중에서, 열적 안정성에서는 NSE/ODA-GO가 가장 효과적이었지만, 기계적 인장 성질이나 산소 차단성에서는 각각 NSE와 ODA-GO가 가장 우수하였다.

• Composites Research
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• 제26권3호
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• pp.170-174
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• 2013

상온 상압 플라즈마 표면처리된 목분을 폴리프로필렌(polypropylene)과 혼합하였을 때 두 재료의 계면에 미치는 영향을 연구하였다. 목분과 폴리프로필렌을 압출기를 통해 기계적으로 혼합한 후 사출기를 이용하여 목분함유량 50 wt% 목분/폴리프로필렌(Wood Plastic Composite, WPC) 복합재를 제조하였다. 플라즈마 표면처리 공정에 가장 적합한 Monomer(모노머)를 찾기 위해 Oxygen, Benzene, CH-4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane(HMDSO) 등 7가지의 모노머에 대해 Contact angle(접촉각)을 측정하여 표면에너지를 계산하였다. 그 결과 HMDSO가 가장 높은 표면에너지를 나타내어 플라즈마 공정의 모노머로 적용하였다. 소수성인 폴리프로필렌과 친수성인 목분을 플라즈마 표면처리를 통하여 목분의 표면을 개질하였고 두 재료의 계면 결합력을 향상시킬 수 있었다. 기계적 물성평가 결과는 인장강도의 경우 최대 7.59%, 굴곡강도의 경우 최대 12.43%가 증가하였다. SEM(Scanning Electron Microscope)을 이용하여 파단면을 관찰하였고 플라즈마 표면처리의 효과를 확인하였다.

• 한국주조공학회지
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• 제17권6호
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• pp.560-568
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• 1997

The dissolution behavior of secondary solidification phases in squeeze cast Al-3.9wt%Cu-1.5wt%Si-1.0wt%Mg has been studied using a combination of optical microscope, image analyzer, scanning electron microscope(SEM), energy dispersive spectrometer(EDS), X-ray diffractometer(XRD) and differential thermal analyzer (DTA). Special emphasis was placed on the investigation of the effects of the nonequilibrium heat treatment on the dissolution of the second solidification phases. Ascast microstructure consisted of primary solidification product of ${\alpha}-Al$ and secondary solidification products of $Al_2Cu$, $Mg_2Si$ and $Al_2CuMg$. Equilibrium and non-equilibrium solution treatments were carried out at the temperatures of $495^{\circ}C$, $502^{\circ}C$ and $515^{\circ}C$ for 3 to 5 hours. The amount of the dissolved secondary phases increased with increasing solution treatment temperature, for example, area fractions of $Al_2Cu$, $Mg_2Si$ and $Al_2CuMg$ were approximately 0%, 1.6% and 4.2% after solution treatment at $495^{\circ}C$ for 5hours, and were approximately 0%, 0.36% and 2% after solution treatment at $515^{\circ}C$ for 5hours. The best combination of tensile properties was obtained when the as-cast alloy was solution treated at $515^{\circ}C$ for 3hours followed by aging at $180^{\circ}C$ for 10 hours. Detailed DTA and TEM study showed that the strengthening behavior during aging was due to enhanced precipitation of the platelet type fine ${\theta}'$ phase.

• 한국의상디자인학회지
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• 제10권3호
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• pp.173-180
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• 2008

Cotton, wool, cotton/wool blended (80:20) and tencel fabrics were treated with low temperature oxygen plasma, enzymes (cellulase or protease), or oxygen plasma-enzyme and they were examined for dyeing and handling properties for environment friendly finishing. The appropriate conditions for cellulase treatment were enzyme concentration of 3g/l, pH of 5, and $60^{\circ}C$ for one hour, and for protease treatment were enzyme concentration of 4g/l, pH of 8, and $60^{\circ}C$ for one hour. The equilibrium uptake of a direct dye on cotton changed with plasma treatment and plasma-cellulase treatment, and the rate of dyeing slightly decreased. When wool was dyed with acid dye, the equilibrium dye uptake did not change with plasma, protease treatment nor plasma-protease treatment, however, the rate of dyeing had increased with plasma-protease treatment. From these results, it is assumed that plasma attacks the surface of the fiber, and enzyme mainly affects the inner part of the fiber. Plasma treatment did not affect mechanical properties related to the handling of fabrics. The handling test showed increased extension at maxmum load(EM), tensile energy(WT) with decreased tensile resilience (RT), and the fabrics became softer but resilience decreased slightly with enzyme treatment. The bending recidity(B), hysteresis of bending moment(2HB), and hysteresis of shear force at five degrees(2HG5) decreased, however, shear stiffness(G) increased. I knew the plasma pre-treatment made fabrics softer with lower koshi(stiffness). The handling of plasma pre-treated fabrics was better than that of enzyme-treated fabrics. When we pre-treated fabrics, the handling test showed decreased coefficient of friction(MIU), geometrical roughness(SMD), while the surface of fabrics became smoother and numeri increased. Even though compression resilience(RC) increased, fukurami(bulky property) and compressive elasticity, decreased due to the linearity of compression-thickness curve(LC) and compression energy(WC).

• 한국염색가공학회지
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• 제17권5호
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• pp.26-36
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• 2005

This study was carried to evaluate mechanical characteristics of Poly(ethylene terephthalate) fabrics (by Kawabata evaluation system(KES)) which was systematically treated with $O_2$ low temperature plasma and chitosan acetate solution. Furthermore, surface structure was investigated by SEM, AFM, air permeability and wettability. Tensile energy(WT), shear rigidity(G) and surface roughness(MIU) properties calculated by KES-FB have increased with increasing plasma treatment time, while bending rigidity(G) and energy of compression(WC) value were decreased compared with those of the untreated. SEM photographs showed the identification of chitosan coating but did not confirm the plasma etching structure. Air permeability was decreased according to plasma treatment time with increasing concentrations of chitosan. The water absorption rate made rapid progress by chitosan treatment.