• Elastomers and Composites
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• 제44권3호
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• pp.260-268
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• 2009

Clay의 표면을 bis[(3-triethoxysilylpropyl)tetra sulfide (TSS)으로 처리하면 clay 표면의 소수성이 증가 될 뿐만 아니라 high temperature vulcanization 형 silicone rubber(HTV)와 화학적 반응이 가능하기 때문에 clay와 silicone rubber 사이의 상용성이 향상될 수 있을 것으로 예상되어 TSS를 이용하여 Na-MMT와 Fe-MMT의 silicate 층 표면에 tetra sulfide 그룹을 도입시킨 Na-$MMTS_4$와 Fe-$MMTS_4$를 각각 제작하였다. 이들 clay를 HTV silicone rubber와 compounding하여 silicone rubber/clay composites를 제작하였으며, clay의 종류 및 표면개질에 따른 silicone rubber 복합체의 열적안정성 및 기계적 물성을 평가하였다.

• 대한기계학회논문집A
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• 제35권10호
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• pp.1199-1203
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• 2011

실리게이트의 층간에 나노충진제를 삽입하여 합성한 고무-점토 나노복합체에 대해 $70-100^{\circ}C$의 고온상태에서 정적 및 동적시험을 수행하여 기존 고무소재보다 기계적 물성이 우수함을 확인하였다. 또한, 본 연구에서는 부품의 취약부위에서 발생하는 최대 그린-라그랑지 변형률을 피로손상변수로 하여 설계 초기단계에서도 짧은 기간에 고무부품의 피로수명을 예측할 수 있는 방법을 개발하여 피로내구성을 평가한 결과, 실제 엔진마운트에 대한 피로시험을 통해 얻어진 피로수명과 예측수명이 비교적 정확하게 예측됨을 확인하였다.

• 폴리머
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• 제27권4호
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• pp.377-384
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• 2003

직접 중합법으로 내충격성 폴리스티렌과 유기화 층상 실리케이트의 나노복합체를 합성하여 점토 첨가에 의한 고무 입자 크기 및 물성의 영향을 조사하였다. 사용한 유기화 점토 중에서는 벤젠기를 지닌 몬모릴로나이트가 폴리스티렌에 우수한 분산 효과를 나타내었다 유기화 점토를 첨가한 경우 X선 회절 분석에서 층간삽입된 피이크를 관찰할 수 있었으나, 고무의 농도가 증가할수록 낮은 각도쪽으로 이동하는 것으로 보아 유기화 점토는 고무에 더 좋은 분산성을 보이는 것으로 파악된다. 분산상인 고무 입자는 점토를 첨가할수록 평균 입자경이 커지며 넓은 입도 분포를 나타내었는데, 이는 점토 첨가에 의해 폴리스티렌 상에 대한 고무 상의 점도비가 더욱 증가하여 평균 입자가 커졌으며 분산계가 불안정해져 넓은 입도 분포를 갖는 것으로 추정된다. 열중량 분석의 결과 나노복합체는 향상된 열적 물성을 보여주었고, 유변 물성을 측정한 결과 점토가 첨가됨에 따라 재료의 복소 점도 및 저장 탄성률은 향상되었다.

• Elastomers and Composites
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• 제24권4호
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• pp.276-289
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• 1989

This study deals with both effects of inorganic fillers to vulcanized rubbers such as NR, CR, EPDM, NBR & SBR and inorganic characteristics of domestic fillers in comparision with hard clay produced in the USA. The results were as follows. 1. Main ingredient of domestic clay "Ha-dong clay" was Halloysite, "No-ha Island" was Pyrophyllite with $\alpha$-Quartz, and both of "Hard clay" & "Hwa-soon clay" were proved to be Kaolinite by XRD, DT-TGA and chemical analysis by XRF. 2. Tensile strength value of SBR compounded with these fillers, was Hard clay $146kg\;f/cm^2$, Kaolinite $123kg\;f/cm^2$, Pyrophyllite $82kg\;f/cm^2$, Halloysite $80kg\;f/cm^2$, precipitated $CaCO_3\;27kg\;f/cm^2$, and ground $CaCO_3$ was $21kg\;f/cm^2$. These results showed the increase of seven times according to filler species. 3. The physical properties of non-crystalline rubbers, such as SBR, NBR & EPDM, compared with NR & CR, have been considerably changed according to crystalline phase, particle size, shape and surface structure of fillers. Especially, tensile strength value in case of SBR & EPDM, was differentiated about 1.5 times by the particle size of fillers. 4. In SBR, physical properties of rubber compounded with Kaolinite which was surface treated with fatty acid and silane, almost approach to the value of hard clay. 5. Delayed cure time of Kaolinite and decrease of rubber properties by $CaCO_3$ can be improved by blending kaolinite & $CaCO_3$ in the ratio of 2:1.

• Elastomers and Composites
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• 제41권4호
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• pp.252-259
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• 2006

천연고무(NR) 라텍스의 원심분리 농축과정의 부산물인 고농도 단백질 함유 스킴 천연고무라텍스(SNRL)를 이용한 고무/점토 나노복합체의 새로운 제조방법을 제시하였다. SNRL과 26% 아크릴로니트릴 함량의 NBR 라텍스의 혼합물에 수분산 유기화 점토(OC)를 첨가하여 혼합하고, 건조 후에 밀혼합과 가황공정을 거쳐 NR/아크릴로니트릴 부타디엔 고무(NBR) 나노복합체를 제조하였다. X-선 회절(XRD) 연구를 통하여 제조된 NR/NBR 블렌드 나노복합체는 층간 삽입이 높은 삽입형과 일부 박리형을 나타내는 것으로 밝혀졌고, 특히 NBR 상이 많은 블렌드에서 그 효과는 더 크게 나타났다. 동적기계적 거동 분석결과 NBR 상이 높은 블렌드가 상용성이 더 높은 것으로 나타났다. NR/NBR 25/75 블렌드가 가장 우수한 기계적 강도를 나타내었다.

• 폴리머
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• 제34권3호
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• pp.215-219
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• 2010

충전제로서 Cloisite$^{(R)}$ 10A와 carbon black을 사용하여 NBR 복합체를 제조하였다. 충전제로서 Cloisite$^{(R)}$ 10A를 사용했을 경우 복합재료의 기계적 물성, 내유성, 그리고 산소 투과성 등이 carbon black을 사용했을 경우 보다 우수하였다. 특히, 복합재료의 경화에 있어서 Cloisite$^{(R)}$ 10A를 사용하였을 경우 scorch 시간과 경화시간이 단축됨을 확인할 수 있었다. 이러한 결과로부터 Cloisite$^{(R)}$ 10A에 삽입되어 있는 알킬 암모늄 이온이 복합재료에 있어 가황 촉진제의 역할을 하고 있음을 알았다.

• Elastomers and Composites
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• 제32권5호
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• pp.295-301
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• 1997

The effects of filler types and compositions on the final properties such as tensile strength, % elongation, hardness, and specific gravity of chloroprene rubber were investigated. The fillers involved in this investigation were HAF-type carbon black, Mistron, and white clay, For each filler, the variation of filler compositions gave almost the linear effects on the all properties investigated. For a fixed filler composition, different filler types gave different influential strength on rubber properties. After linearlization of experimental data with respect to each filler composition, the simple linear addition of each property with respect to filler compositions was applied to predict the final properties of the filler included rubber systems. For the chloroprene rubber system including the fillers composed of Mistron(25phr)/HAF(20phr)/clay(35phr), the predicted properties were well in accordance with the experimental results. Similar results were obtained for other additives such as processing oil and accelerator.

• 한국환경보건학회지
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• 제44권3호
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• pp.238-243
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• 2018

Objectives: The purpose of this study was to determine skin adhesion rate of children's modeling clay for exposure assessment. Methods: Children's modeling clays were classified into 10 categories as PVA clay, PVA soft clay, starch-based clay, foam clay, rubber clay, oil clay, muddy clay, terra clay, paper clay and slime. A total of 26 children's clay goods was selected. Moisture content (%) and hardness of clays were measured. Five adults aged 20 to 25were recruited for experiment. Gravimetric difference of modeling clay was determined after 3 minutes playing time. Skin adhesion rate ($g/min/cm^2$) was estimated bythe amount of skin adhesion per minute (g/min) and each individual's palm surface area ($cm^2$). Results: Twenty four of the 26 children's modeling clay products were adhesive to skins. Two products of foam and rubber clay were not adhered to skin. For the 24 products, the average skin adhesion rate was $5.5{\times}10^{-4}{\pm}4.0{\times}10^{-4}g/min/cm^2$. The highest skin adhesion rate was $1.3{\times}10^{-3}{\pm}4.4{\times}10^{-4}g/min/cm^2$ for paper clay. The lowest skin adhesion rate was $4.6{\times}10^{-5}{\pm}1.1{\times}10^{-4}g/min/cm^2$ for oil clay. The skin adhesion rate was increased with increase of moisture content. Adhesion rates of some clays were varied by person and testing trials. Conclusion: The study determined skin adhesion rate of children's modeling clay. The adhesion rate is useful for exposure and risk assessments and setting safety guideline to protect children's health.

• Carbon letters
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• 제10권3호
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• pp.190-197
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• 2009

Various silanes, amino silane, vinyl silane, sulfur silane (TESPD), and ZS (TESPD/zinc soap complex), are added into chlorinated isobutylene-isoprene copolymer (CIIR)/soft clay/carbon black (CB) and CIIR/hard clay/CB compounds and they are investigated with respect to the vulcanization characteristics, the processability, and the mechanical properties. Comparing hard clay and soft clay filled compounds, hard clay (Suprex) filled system shows a higher die C tear than the soft clay (GK) filled one. The other properties (Mooney, extrusion torque/pressure, torque rise ($M_H-M_L$), modulus at 300%) are close to each other. Among various silanes, the ZS treated hard clay (Suprex) compound shows the highest mechanical property following hard clay(S)/vinyl silane(V) and soft clay(GK)/vinyl silane(V) compounds. The TESPD and the ZS effectively helps a formation of a strong 3-dimensional network structure between silica and CIIR via coupling reaction due to bifunctional nature of TESPD. In addition to that, the ZS added compounds show both a better processability and mechanical properties compared to the S2 ones at low concentration due to improved compatibility between zinc soap and CIIR matrix. Only the ZS added compound shows both improved processabilities (Mooney, Extrusion torque-& pressure) and improved mechanical properties (degree of crosslinking, elongation modulus, tear, and fatigue to failure counts) on both CIIR/hard clay/CB and CIIR/soft clay/CB compounds.

• Carbon letters
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• 제10권2호
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• pp.101-108
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• 2009

Various silanes, amino silane, vinyl silane, TESPD, and ZS (TESPD/zinc soap complex), are added into chlorinated isobutylene-isoprene copolymer (CIIR)/hard clay/carbon black (CB) compound and they are investigated with respect to the vulcanization characteristics, the processability, and the mechanical properties. In hard clay/CB filled system, only ZS silane added compound shows both lower Mooney viscosity and extrusion torque while vinyl silane added compound showed only a lower extrusion torque. All the ZS added compounds showed the lowest viscosity among them. The silane added compounds showed an increased modulus. In 'fatigue to failure' count test, the ZS added compound showed superior counts compared to other silane (amino, vinyl, TESPD) added compounds. The mechanical properties were significantly increased when the S2 and ZS were added into CIIR/hard clay/CB compound. The ZS added compounds showed a significant improvement on elongation modulus.