• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.76-76
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• 2015

PVD에 의한 증착 대상 물질인 Ti, AlSi, Cr 및 각각의 타겟 전류, 바이어스, 압력 조건 들을 설계하여 적용시켰으며 PECVD와 CBC 코팅을 조합하여 발생되는 새로운 나노 멀티박막의 특성을 본 연구에서는 시험분석 및 평가하였다. 코팅층 깊이에 따른 조성 변화는 XPS를 이용하였으며 미세조직 및 표면 상태는 FE-SEM을 이용한 정밀 분석을 실시하였다. 또한, 박막의 경도는 나노인덴터를 이용하여 박막 자체의 경도만을 분석하였다. 한편, Pin-on-disk 방식의 마모시험기를 이용하여 표면조도와 상대재의 처리 상태에 따른 마찰계수를 시험 평가하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.49-54
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• 2014

Background: Hydrogels are a class of polymers that can absorb water or biological fluids and swell to several times their dry volume, dependent on changes in the external environment. In recent years, hydrogels and hydrogel nanocomposites have found a variety of biomedical applications, including drug delivery and cancer treatment. The incorporation of nanoparticulates into a hydrogel matrix can result in unique material characteristics such as enhanced mechanical properties, swelling response, and capability of remote controlled actuation. Materials and Methods: In this work, synthesis of hydrogel nanocomposites containing magnetic nanoparticles are studied. At first, magnetic nanoparticles ($Fe_3O_4$) with an average size 10 nm were prepared. At second approach, thermo and pH-sensitive poly (N-isopropylacrylamide -co-methacrylic acid-co-vinyl pyrrolidone) (NIPAAm-MAA-VP) were prepared. Swelling behavior of co-polymer was studied in buffer solutions with different pH values (pH=5.8, pH=7.4) at $37^{\circ}C$. Magnetic iron oxide nanoparticles ($Fe_3O_4$) and doxorubicin were incorporated into copolymer and drug loading was studied. The release of drug, carried out at different pH and temperatures. Finally, chemical composition, magnetic properties and morphology of doxorubicin-loaded magnetic hydrogel nanocomposites were analyzed by FT- IR, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM). Results: The results indicated that drug loading efficiency was increased by increasing the drug ratio to polymer. Doxorubicin was released more at $40^{\circ}C$ and in acidic pH compared to that $37^{\circ}C$ and basic pH. Conclusions: This study suggested that the poly (NIPAAm-MAA-VP) magnetic hydrogel nanocomposite could be an effective carrier for targeting drug delivery systems of anti-cancer drugs due to its temperature sensitive properties.

• 센서학회지
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• 제17권4호
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• pp.281-288
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• 2008

Polyacrylonitrile(PAN)/metal oxide(MO) nanocomposite mats with a thickness of 0.12 mm were electrospun by adding 0 to 10 wt% of MO nanoparticles ($Fe_2O_3$, ZnO, $SnO_2$, $Sb_2O_3-SnO_2$) into PAN. Pt electrode was patterned on $Al_2O_3$ substrate by DC sputtering and then the PAN(/MO) mats on the Pt patterned $Al_2O_3$ were electrically wired to investigate the $CO_2$ gas sensing properties. As the MO content rose, the fiber diameter decreased due to the presence of lumps caused by the presence of MOs in the fiber. The PAN/2% ZnO mat revealed a faster response time of 93 s and a relatively short recovery of 54 s with a ${\Delta}R$ of 0.031 M${\Omega}$ at a $CO_2$ concentration of 200 ppm. The difference in sensitivity was not observed significantly for the PAN/MO fiber mats in the $CO_2$ concentration range of 100 to 500 ppm. It can be concluded that an appropriate amount of MO nanoparticles in the PAN backbone leads to improvement of the $CO_2$ gas sensing properties.

• 한국분말재료학회지
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• 제22권3호
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• pp.157-162
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• 2015

SKD11(ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol.% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out SKD11 carbon nanocomposites.

• 폴리머
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• 제37권3호
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• pp.308-315
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• 2013

본 연구에서는 실리카 나노 입자의 표면개질을 위해 실란 커플링제인 bis[3-(triethoxysilylpropyl)]tetrasulfide(TESPT)를 사용하여 표면개질 반응을 수행하였다. 반응온도, 반응시간 및 TESPT 투입량의 변화가 실리카 표면개질 반응에 미치는 영향을 Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TGA), elemental analysis(EA) 및 고체 $^{13}C$ 및 $^{29}Si$ cross-polarization magic angle spinning(CP/MAS) nuclear magnetic resonance spectroscopy(NMR)를 사용하여 분석하였다. 실리카 대비 투입되는 TESPT의 투입량을 증가시킬수록 $3746cm^{-1}$의 실리카의 고립 실란올(isolated) 피크의 세기는 줄어들었고, $2938cm^{-1}$의 TESPT의 $-CH_2$기에 의한 피크의 세기는 증가하였다. 또한 TESPT로 표면 개질된 실리카가 SBR 복합체의 기계적 물성에 미치는 영향과 SBR 기질 내에서 실란 커플링제로 표면 처리된 실리카의 분산정도를 universal testing machine(UTM)과 field emission scanning electron microscope(FE-SEM)를 이용하여 각각 측정하였다. 실험 결과 개질되지 않은 본래(pristine) 실리카를 20 phr(parts per hundred of rubber) 넣은 SBR 나노복합체에 비해 개질된 실리카 20 phr를 넣은 SBR 복합체의 인장강도는 5.65에서 9.38 MPa, 100% modulus는 1.62에서 2.73 MPa로 각각 증가하였으나, 파괴점 신장률은 349.6에서 298.9%로 조금 감소되었으며, SBR 기질 내의 실리카 분산성은 TESPT로 처리된 실리카가 본래 실리카에 비해 우수하였다.

• 한국세라믹학회지
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• 제51권1호
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• pp.7-10
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• 2014

Abalone shell is composed of 95 wt% $CaCO_3$ platelets and 5 wt% of a protein-rich organic matrix which acts as an adhesive layer, connecting aragonite tablets, thus maintaining the structural integrity of the composite. By mimicking abalone shell, we prepared a silicate plate/polymer nanocomposite by infiltrating PMMA between silicate layers and warm-pressing them at $200^{\circ}C$ for 1 h under 15 tons to make organic-inorganic composite materials. To examine the organic-inorganic composite materials after the warm-pressing procedure, the composite sample was analyzed with FE-SEM and TG. The bending strengths and densities of the composites prepared by a silicate plate and PMMA after the warm-pressing process were ~140 MPa and 1.5, respectively.