• Korean Chemical Engineering Research
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• 제51권5호
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• pp.580-586
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• 2013

본 연구에서는 투과증발 공정에서 지지체에 따른 투과특성의 차이를 알아보기 위해 고분자 지지체 복합막과 세라믹 지지체 복합막을 제조하였다. 고분자 지지체로는 polyvinylidene fluoride (PVDF)를 사용하였으며 세라믹 지지체로는 $a-Al_2O_3$ 를 사용하였다. 활성층으로는 각각의 지지체에 고무상 고분자인 polydimethoxysilane (PDMS)를 코팅하였다. 제조한 복합막의 구조와 특성을 살펴보기 위해 SEM, contact angle, XPS로 분석하였으며, 이를 투과증발 공정에 적용하여 다성분계의 혼합용액에서 복합막의 지지체에 따른 투과 특성을 알아보았다. 투과 증발 실험 결과 세라믹 지지체 복합막의 투과 플럭스는 $250.87g/m^2h$로 고분자 지지체 복합막의 $159.64g/m^2h$ 보다 높은 투과 플럭스를 나타내었다. 그러나 선택도의 경우 고분자 지지체 복합막이 31.98로 20.66인 세라믹 지지체 복합막보다 더 높게 나타나는 것을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.319-319
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• 2010

Dye-sensitized solar cells (DSSCs) based on plastic substrates have attracted much attention mainly due to extensive applications such as ubiquitous powers, as well as the practical reasons such as light weight, flexibility and roll-to-roll process. However, conventional high temperature fabrication technology for glass based DSSCs, cannot be applied to flexible devices because polymer substrates cannot withstand the heat more than $150^{\circ}C$. Therefore, low temperature fabrication process, without using a polymer binder or thermal sintering, was required to fabricate necked $TiO_2$. In this presentation, we proposed polymer-inorganic composite photoelectrode, which can be fabricated at low temperature. The concept of composite electrode takes an advantage of utilizing elastic properties of polymers, such as good impact strength. As an elastic material, poly(methyl methacrylate) (PMMA) is selected because of its optical transparency and good adhesive properties. In this work, a polymer-inorganic composite electrode was constructed on FTO/glass substrate under low temperature sintering condition, from the mixture of PMMA and $TiO_2$ colloidal solution. The effect of PMMA composition on the photovoltaic property was investigated. Then, the enhanced mechanical stability of this composite electrode on ITO/PEN substrate was also demonstrated from bending test.

• Journal of the Korean Wood Science and Technology
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• 제31권3호
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• pp.1-10
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• 2003

Shredded waste newspapers, waste acrylic raw fibers, and urea-formaldehyde (UF) adhesives, at 10% by weight on raw material, were used to produce recycled waste paper-waste acrylic raw fiber composite boards in laboratory scale experiments. The physical and mechanical properties of fire retardant treated recycled waste paper-waste acrylic raw fiber composite boards were examined to investigate the possibility of using the composites as internal finishing materials with specific gravities of 0.8 and 1.0, containing 5, 10, 20, and 30(wt.%) of waste acrylic raw fiber and 10, 15, 20, and 25(wt.%) of fire retardant (inorganic chemical, FR-7^®) using the fabricating method used by commercial fiberboard manufacturers. The bending modulus of rupture increased as board density increased, decreased as waste acrylic raw fiber content increased, and also decreased as the fire retardant content increased. Mechanical properties were a little inferior to medium density fiberboard (MDF) or hardboard (HB), but significantly superior to gypsum board (GB) and insulation board (IB). The incombustibility of the fire retardant treated composite board increased on increasing the fire retardant content. The study shows that there is a possibility that composites made of recycled waste paper and waste acrylic raw fiber can be use as fire retardant internal finishing materials.

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2451-2456
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• 2011

0.5mm 크기의 타원형 무기분말을 충전한 폴리우레탄 폼 복합재료에 대한 가교반응의 특성과 후가교처리에 따른 기계적 물성의 변화에 대하여 생성반응의 온도 측정, TGA, 및 인장시험을 이용하여 연구하였다. 중량비로 20% 정도를 충전하는 $CeO_2$ 무기분말(Ce500)을 충전한 샘플 폼복합재료는 10분 이내에 $100^{\circ}$ 정도의 최고 반응속도점 온도에 도달하였으며, 만들어진 샘플의 열분해반응은 약 $250^{\circ}$ 부근의 저온 열분해와 약 $350^{\circ}$ 부근의 고온 열분해의 이중모드로 일어나는 것이 관찰되었다. Kissinger의 해석방법에 의한 분해활성화에너지는 저온영역에서의 열분해에 대하여서는 117.4kJ/mol이며 고온영역에 대해서는 139.4kJ/mol의 값을 각각 나타내었다. $160^{\circ}C$에서의 샘플의 후가교 처리시간에 따른 기계적 성질은 후가교 시간에 따라서 파단응력이나 경도는 크게 변하지 않는 것으로 나타났으나 파단신율은 최대 1.72배까지 증가하였으며, 본 실험에서 사용된 샘플의 경우 $160^{\circ}C$, 7시간 정도의 후가교 시간이 가장 적절한 후가교 조건으로 생각되었다.

• 한국세라믹학회지
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• 제34권8호
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• pp.854-860
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• 1997

The tribological property of ceramics is very important for use in seal rings, pump parts, thread guides and mechanical seal, etc. In the present study, which RBSC/graphite composites were manufactured by adding graphite powders with different particle sizes to mixtures of SiC powder, metallic silicon, carbon black and alumina, effects on the tribological property of each RBSC/graphite composite was investigated in accordance with the particle size of the added graphite powder. The water absorption, the bending strength and the resistance for the friction and wear were measured, and the crystalline phase and the microstructure were respectively examined by using XRD and SEM. In case that the particle size of the graphite powder was fine(2${\mu}{\textrm}{m}$), the formation of $\beta$-SiC was accelerated, thereby making the increase of the bending strength and the decrease of the water absorption, but no improvement for the tribological properties. Furthermore, in case that the particle size of the graphite powder was some large(88~149${\mu}{\textrm}{m}$), the formation of $\beta$-SiC was not accelerated, to thereby make the decrease of the bending strength and the increase of the water absorption, but the improvement for the tribological property of only the composite having the graphite powder of 20 vol%. In addition, in case that the particle size distribution of the graphite powder was large (under 53 ${\mu}{\textrm}{m}$), there was no improvement for every properties. However, the composites, which the graphite powder with the particle size of 53~88 ${\mu}{\textrm}{m}$ was added in 10~15 vol%, had the most increased resistance for the friction and wear which show the worn out amount of 0.4~0.6$\times$10-3 $\textrm{cm}^2$, and the value of the bending strength is 380~520 kg/$\textrm{cm}^2$.

• 멤브레인
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• 제25권5호
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• pp.456-463
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• 2015

본 연구에서는 고온에서 우수한 전도성을 가지는 전해질막의 개발을 위하여 신규한 실란계 무기물을 합성하였으며, 이를 이용하여 제조된 분리막의 특성평가가 진행되었다. 탄화수소계열 고분자인 SPAES를 합성하여 고분자 물질로 사용하였으며, 높은 이온전도성을 가지는 무기물의 제조를 위하여 silica, phosphate, zironium계 물질을 졸겔법을 이용하여 복합화 시켰다. 각 조성의 몰비를 조절하여 세 가지 종류의 무기물을 제조하였으며 조성에 따른 물성변화를 관찰하였다. EDX 분석결과 제조된 무기물은 고분자 분리막 내에 고르게 분산이 되는 것을 확인하였다. 친수성을 가지는 무기물의 도입을 통하여 분리막 내에 이온을 전달할 수 있는 수분채널이 형성되어 함수율이 증가가 됨을 확인하였다. 또한 zirconium계 무기물의 함량이 높을수록 고온에서 전도도가 향상되는 결과를 확인하였으며 복합화된 실리카는 저온 가습조건에서 이온전도도가 향상되는 결과를 나타내었다.

• 멤브레인
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• 제20권1호
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• pp.21-28
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• 2010

염료감응형 태양전지에 사용되기 위한 유기/무기 복합소재를 합성하였다. 다양한 분자량(600, 1,500, 2,000, 3,400)의 polyethylene glycol 양 끝단을 ethoxysilane기로 치환하여 전구체를 제조하였으며, 전구체간의 졸-겔 반응을 통하여 복합소재를 합성하였다. 전해질막은 유기/무기 복합소재를 KI 및 $I_2$로 도핑하여 제조하였으며, 제조한 전해질의 이온전도도 특성을 측정하였다. 전해질막의 이온전도도는 원료로 사용한 PEG에 크게 영향을 받았으며 가장 높은 이온전도도는 분자량 2,000의 PEG를 사용한 전해질막에서 볼 수 있었다. 복합전해질막은 이온전도도에 있어서 큰 향상을 보였다. PEO 전해질막에 비하여 분자량 2,000의 PEG를 사용하여 제조한 복합전해질막은 월등하게 높은 이온전도도를 보였다.

• 한국세라믹학회지
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• 제31권4호
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• pp.367-374
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• 1994

Inorganic-organic composite was made through sol-gel process. Possible range for hosting organic dye was investigated with various composition. The transmittance of the composite was the most important condition for a host was increased to 90% with decreasing HCl as a catalyst. Clear absorbance peak was obtained by decreasing concentration of organic dye, fluorescent intensity was increased and transmittance was decreased with rising gelling temperature.

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.341-346
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• 1994

To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atel- ocollagen was produced. The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2005년도 수소연료전지공동심포지움 2005논문집
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• pp.233-240
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• 2005

A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxidenanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of inoranic oxide content were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase In inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nafion membrane.