• 치위생과학회지
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• 제10권3호
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• pp.177-183
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• 2010

탄성 고무인상재의 종류인 폴리설파이드(polysulfide), 폴리이써(polyether), 부가중합형 실리콘(addition silicone)에서 점주도(consistency)가 Type III인 인상재를 각각 1종류 선택하여 증류수 $3.3{\mu}l$를 떠뜨려 접촉각을 측정하고, 세 종류의 인상체에 치과용 경석고를 부어 작업모형을 만들고 표면을 관찰하였다. 접촉각 측정은 전자동접촉 각 측정시스템(DM-700, KYOWA, Japan)을 이용하였고 작업모형의 표면관찰은 전계 방사형 주사 전자현미경(JSM-6700F, JEOL Ltd., JAPAN)을 이용하여 다음과 같은 결론을 얻었다. 1) 초기 접촉각의 평균과 표준편차는 부가중합형실리콘, 폴리이써, 폴리설파이드 제품이 각각 $91.3^{\circ}{\pm}20.5$, $90.0^{\circ}{\pm}2.2$, $101.5^{\circ}{\pm}2.3$로 평균값은 유사하게 나타났으나 부가중합형실리콘의 표준편차값에서 큰 차이를 보여줬다. 이는 술자의 술식에 따라 항상 일정한 특성을 보여주지 않는 다는 것이다. 2) 시간이 흐를수록 부가중합형실리콘 제품은 다른 두 종류에 비해 접촉각이 급속히 감소함을 관찰 할 수 있었고, 초기접촉각이 $91.3^{\circ}$이며 25초 후 $29.4^{\circ}$로 급격히 감소했다. 3) 폴리이써 제품은 초기접촉각이 $101.5^{\circ}$에서 25초 후의 접촉각 $90.7^{\circ}$이였고, 폴리설파이드 제품은 초기접촉각이 90.0에서 25초 후의 접촉각 84.2로 변화가 거의 일어나지 않았고 그 각도도 부가중합형실리콘에 비해 컸다. 4) 세 종류의 탄성고무인상재에서 시간이 흐름으로써 관찰된 접촉각은 유의성이 있었다(p<0.001). 5) 작업모형의 표면관찰에서 부가중합형실리콘이 가장 치밀했고, 그 다음 폴리설파이드, 폴리이써 순서였다. 따라서 탄성고무 인상재에 있어서 접착각이 작은 부가중합형 실리콘은 폴리이써나 폴리설파이드 제품에 비해 더 치밀한 작업모형을 얻을 수 있었고 세 종류의 인상재접착각에서 큰 유의성을 보였다. 그러나 부가중형 실리콘은 접촉각의 편차가 커 술자의 주의가 필요한 것으로 나타났고 폴리설파이드 제품과 폴리이써 제품은 20~25초 후 접촉각이 최초 접촉각과 큰 차이를 보이지 않아 소수성 제품으로 인상채득 시 주의가 요망되는 것으로 보여진다. 향후 Vitro 상태에서 인상재에 영향을 미치는 여러가지 요인들에 대한 계속적인 연구의 필요성을 느낀다.

• 접착 및 계면
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• 제2권4호
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• pp.1-9
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• 2001

실리콘 실란트는 실리콘폴리머, 가소제(plasticizer), 가교제(crosslinker), 충전제(filler), 촉매(catalyst), 첨가제(additive) 등으로 제조할 수 있으며, 실란트의 실용특성에는 각 제조변수의 종류와 혼합비율이 크게 영향한다. 알코올형 실리콘 실란트는 최근들어 환경적인 이점 때문에 그 사용이 늘고 있다. 본 연구에서는 상온경화형 일액형 알코올형 실리콘 실란트를 PDMS(polydimethylsiloxane)의 점도를 달리하여 제조한 후 그 접착특성을 평가하였다. 또한 점도 20000과 80000 cps의 PDMS를 혼합 사용하고 가교제, 가소제, 촉매 등의 함량을 변화시켜가면서 실란트를 제조하고 접착특성을 평가하였다. 또한 각 실란트의 제조과정 중의 반응온도 변화를 기록하여 적절한 제조조건을 얻도록 하였다. 실란트 제조시 혼합물의 온도가 $40^{\circ}C$ 이하가 되도록 제조변수의 조성을 조절하여 적합한 물성의 실란트를 제조할 수 있었다. 피착재에 따라 접착력이 달라졌으며, 유리/유리 > 유리/알루미늄 > 알루미늄/알루미늄 순으로 나타났다. 실란트의 신장률은 폴리머 점도와 가소제의 함량 증가에 따라 증가하였으며, 강도는 가교제와 가소제 함량 감소와 촉매함량 증가에 따라 증가하였다.

• 분석과학
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• 제8권4호
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• pp.623-630
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• 1995

Silicone rubber-based sodium-selective membranes are developed for solid-state ion sensors. It was shown that the potetiometric performance of SR-based membranes are greatly dependent on the type of neutral carriers employed; among the three ionophores, N,N,N',N'-tetracyclohexyl-1,2-phenylenedioxydiacetamide (ETH 2120), bis[(12-crown-4)methyl]dodecylmethylmalonate (D12C4DMM) and monensin methyl ester (MME), examined, only ETH 2120 was compatible with the SR-based matrix. Addition of about 20 wt% plasticizer to the SR-based matrix provided the resulting membranes with potentiometric properties essentially equivalent to those of the corresponding PVC-based membranes. Owing to the strong adhesive strength of SR-based membranes, the CWEs coated \vith those membranes exhibited long lifetime with conventional electrode-like performance. Blending of PU into the SR matrix increased the lifetime of CWEs from two weeks to one month.

• 조명전기설비학회논문지
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• 제27권9호
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• pp.1-5
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• 2013

We developed high-efficient 6W-LED package with simple structure by applying Heat Slug and silicone-reflector. LED package was manufactured in $8.5{\times}8.5mm$ sized multi-chip structure having thickness of $500{\mu}m$ achieved by bonding silicon-reflector with prepreg on top of the plate after implementing the reflector placed on copper substrate Half Etching by thickness of $200{\mu}m$. The luminous flux, luminous efficacy, correlated color temperature, color rendering index and thermal resistance of developed LED was evaluated, and it verified the application of products by applying it to 120W-LED road luminaires through simulation. The luminous efficacy of LED package reached over 130lm/W, and it is possible to be manufactured into 120W-LED road luminaires using 18 packages. In addition, the simulation results showed average of horizontal illuminance and overall illuminance uniformity that is suitable for three-lane road.

• Design & Manufacturing
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• 제17권1호
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• pp.1-5
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• 2023

In multi-material injection molding, since two or more materials with different process conditions are used, it is essential to maximize process efficiency by operating the cooling or heating system to a minimum. In this study, Liquid silicone rubber (LSR) that can be cured at a low temperature suitable for the multi-material injection molding was selected and the cure behavior according to the process conditions was analyzed through differential scanning calorimetry (DSC). Dynamic measurement results of DSC with different heating rate were obtained, and through this, the total heat of reaction when the LSR was completely cured was calculated. Isothermal measurement results of DSC were derived for 60 minutes at each temperature from 80 ℃ to 110 ℃ at 10 ℃ intervals, and the final degree of cure at each temperature was calculated based on the total heat of reaction identified from the Dynamic DSC measurement results. As the result, it was found that when the temperature is lowered, the curing start time and the time required for the curing reaction increase, but at a temperature of 90 ℃ or higher, LSR can secure a degree of cure of 80% or more. However, at 80 ℃., it was found that not only had a relatively low degree of curing of about 60%, but also significantly increased the curing start time. In addition, in the case of 110 ℃, the parameters were derived from experimental result using the Kamal kinetic model.

• Design & Manufacturing
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• 제17권2호
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• pp.27-32
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• 2023

Liquid silicon rubber (LSR) has fine thermal compatibility and is widely used in various fields such as medical care and automobiles because it is easy to implement products with good fluidity. With the recent development of flexible sensors, the focus has been on manufacturing conductive elastomers, such as silicone as elastic materials, and carbon black, CNT, and graphene are mainly used as nanomaterials that impart conductive phases. In this study, mechanical behavior and curing behavior were measured and analyzed to manufacture a CB-LSR complex by adding Carbon Black to LSR and to identify properties. As a result of the compression test, the elastic modulus tended to increase as carbon black was added. When the swelling test and the compression set test were conducted, the swelling rate tended to decrease as the content of carbon black increased, and the compression set tended to increase. In addition, DSC measurements showed that the total amount of reaction heat increased slightly as the carbon black content increased. It is considered that carbon black was involved in the crosslinking of LSR to increase the crosslinking density and have a positive effect on oil resistance reinforcement.

• 대한치과보철학회지
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• 제38권2호
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• pp.191-199
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• 2000

Wettability of addition silicone impression material is very important property for making an accurate restoration. This study examined the impression quality in clinical condition and the wettability of impression and die material. Four commercially available addition silicone impression material (Express, Examix, Contrast, Perfect) and three die materials (Die-Keen, Vel-Mix, Fuji-Rock) were studied. A total of 50 putty/wash and heavy body/wash impressions of wet intact permanent molar teeth were examined for definition of the gingival sulcus reproduction and then classified in quality ranking. The percentage of the sulcus reproduction ability of each material was calculated from the sulcus depths of cross-sectioned epoxy resin casts from the impressions and clinically measured sulcus depths, The same impression materials were used to produce 3 groups of die stone casts form void entrapment die had been exposed to milk. Voids in the impression body and stone casts ere counted under a stereoscopic microscope. From the experiment, the following results were obtained : 1. Sulcus reproduction ability of additional silicone impression material were diminished in order of Express, Examix, Perfect, Contrast. The significant difference was found between Perfect and other material. Heavy body/wash combination was superior In putty/wash method n Perfect impression material. 2. In direct observation, Contrast showed least void in impression body but correlations ere not found between sulcus reproduction and void production. 3. In void entrapment laboratory test, wettability were diminished in order of Examix, Contrast, Express, Perfect. Clinical impression recording seems not to correlate with laboratory test. 4. The wettability of die material to impression material was not different in Express, Examix, Contrast. But, in Perfect, Die-Keen had superior wettability to others.

• Elastomers and Composites
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• 제51권2호
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• pp.113-121
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• 2016

Magneto-rheological elastomer (MRE) is a material which shows reversible and various modulus under magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, silicone rubber was used as a matrix of MREs. Carbonyl iron particle (CIP) was used to give magnetic field reactive modulus of MRE. The surface of the CIP was modified with chemical reactants such as silane coupling agent and poly(glycidyl methacrylate), to improve interfacial adhesion between matrix and CIP. The mechanical properties of MREs were measured without the application of magnetic field. The results showed that the tensile strength was decreased while the hardness was increased with the addition of CIP. Also, surface modification of CIP resulted in the improvement of physical properties of MRE, but the degree of orientation of CIP became decreased. The analysis of MR effect was carried out using electromagnetic equipment with various magnetic flux. As the addition of CIP and magnetic flux increased, increment of MR effect was observed. Even though the surface modification of CIP gave positive effect on the mechanical properties of MRE, MR effect was decreased with the surface modification of CIP due to decrease of CIP orientation. Throughout this study, it was found that the loading amounts of CIP affected the mechanical properties of MRE, and surface property of CIP was an important factor on MR effect of MRE.

• Bulletin of the Korean Chemical Society
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• 제27권8호
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• pp.1175-1180
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• 2006

Si-C composites were prepared by the carbonization of polyaniline (PAn) coated on silicone powder. The physical and electrochemical properties of the Si-C composites were characterized by particle-size analysis, X-ray diffraction, scanning electron microscopy, and battery electrochemical tests. The average particle size of Si was increased by the coating of Pan but somewhat reduced by the carbonization to give silicone-carbon composites. The co-existence of crystalline silicone and amorphous-like carbon was confirmed by XRD analyses. SEM photos showed that the silicone particles were well covered with carbonaceous materials, depending on the PAn content. Si-C$\mid$Li cells were fabricated using the Si-C composites and tested using galvanostatic charge-discharge. Si-C$\mid$Li cells gave better electrochemical properties than Si|Li cells. Si-C$\mid$Li cells using Si-C from HCl-undoped precursor PAn showed better electrochemical properties than precursor PAn doped in HCl. The addition of an electrolyte containing 4-fluoroethylene carbonate (FEC) increased the initial discharge capacity. Also, another electrochemical test, the galvanostatic charge-discharge test with GISOC (gradual increasing of the state of charge) was carried out. Si-C(Si:PAn = 50:50 wt. ratio)|Li cell showed 414 mAh/g of reversible specific capacity, 75.7% of IIE (initial intercalation efficiency), 35.4 mAh/g of IICs (surface irreversible specific capacity).

• Elastomers and Composites
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• 제45권2호
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• pp.87-93
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• 2010

내화재료는 건축물에서 화재사고로부터 화염을 차단하기 위해 사용된다. 본 연구에서는 실리콘 고무에 무기계 난연제인 aluminium trihydroxide(ATH, $Al(OH)_3$)와 magnesium dihydroxide(MDH, $Mg(OH)_2$)를 첨가한 복합체를 기계적 교반으로 제조한 후 내화성능향상에 관한 연구를 진행하였다. 내화재료의 열 특성분석을 위해 TGA를 사용하였고, rheometer를 이용해 유변학적 분석을 하였다. 내화특성을 분석하기 위해 gas torch를 이용하였다. 본 연구를 통하여 ATH와 MDH가 첨가되면 실리콘 고무의 내화성능이 향상됨을 알 수 있었다.