• Macromolecular Research
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• 제8권6호
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• pp.285-291
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• 2000

Influence of silane coupling agent, bis-(3-(triethoxisilyl)-propyl)-tetrassulfide, on cure characteristics and bound rubber content of filled styrene-butadiene rubber (SBR) compounds and on physical properties of the vulcanizates was studied. Carbon black-filled and silica-filled compounds were compared. Content of the bound rubber increased with increased content of the silane coupling agent and this trend was shown more clearly in the silica-filled compounds. Optimum cure time of the carbon black-filled compound increased with increase of the silane content, while that of the silica-filled one decreased. Cure rate of the carbon black-filled compound became slower as the silane content increased while that of the silica-filled one became faster. By increasing the silane content, the minimum torque decreased and the delta torque increased. Physical properties of the silica-filled vulcanizate were found to be improved by adding the silane coupling agent. However, for the carbon black-filled vulcanizates, the tensile strength and tear resistance decreased with increase of the silane content. The differences between the carbon black-filled and silica-filled compounds were explained by difference in the reactivities of the fillers with the silane.

• Elastomers and Composites
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• 제37권3호
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• pp.170-176
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• 2002

공정조제의 성분 및 함량이 styrene-butadiene rubber (SBR) 배합고무의 유변학적 특성과 기계적 물성에 미치는 영향을 조사하였다. 공정조제로 지방산, 지방산 유도 금속염, 에스테르 알코올, 아미드 성분을 단독 혹은 혼합한 5종의 상용제품을 선택하였다. 공정조제 첨가에 따른 무니점도와 전단점도의 감소는 금속염이 주성분인 공정조제가 가장 컸고, 고분자량의 지방산 알콜이나 에스터의 함량이 높은 공정조제가 낮았다. 공정조제의 함량증가에 따라 인장 모듈러스는 감소하고, 발열은 증가하는 경향을 나타내었지만, 극한물성인 인장강도와 파단신장율에는 그다지 큰 영향을 미치지 않았다.

• Elastomers and Composites
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• 제48권2호
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• pp.103-113
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• 2013

실리카와 실란을 포함하는 고무 복합체의 최적 배합조건을 찾기 위하여 배합온도와 시간을 달리한 고무복합체의 특성을 평가하였다. 고무복합체의 제조를 위한 배합온도는 $120^{\circ}C$, $140^{\circ}C$, $160^{\circ}C$의 다양한 배합시간으로 배합한 후 고무복합체의 특성을 평가하였다. 배합시간이 증가할수록 점도의 감소와 결합고무가 증가하였으나, 배합시간의 증가에 따른 점도의 변화는 배합온도가 낮을수록 크고, 결합고무의 증가속도는 온도가 높을수록 크게 나타났다. 낮은 온도인 $120^{\circ}C$인 경우 배합 시간이 바뀌어도 가교 속도는 거의 일정한 반면 10분 이하의 배합 시간에서는 분산이나 반응이 충분치 않음을 동적 점탄성과 분산 평가 등을 통하여 알 수 있었다. 반대로 높은 온도에서는 충분한 반응에 의하여 동적 점탄성 특성 등이 우수한 것으로 나타나지만 가교 속도나 물성의 변화 등이 매우 민감하고 과도한 결합고무의 형성 때문에 적합한 온도 조건이 아님을 확인하였고, 변성 S-SBR 실리카 배합에서는 $140^{\circ}C$에서 10분 정도의 배합이 분산과 실리카-실란 결합의 최적 조건임을 확인하였다.

• Elastomers and Composites
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• 제48권3호
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• pp.201-208
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• 2013

본 연구는 황과 가교 촉진제의 함량이 달리 적용된 acrylonitrile styrene-butadiene rubber (AN-SBR)/silica 컴파운드가 타이어 트레드 컴파운드의 특성에 미치는 영향에 대해 연구하였다. 실험 결과, 가교제 및 가교촉진제의 함량이 증가할수록 가교 반응성이 증대되어 가교속도 및 컴파운드의 가교도가 상승하였다. 또한 내마모 특성 뿐만 아니라 경도, 모듈러스와 같은 컴파운드의 기계적 특성은 높은 가교도에 기인하여 향상되었다. 동적 점탄 특성에서는 가교도의 증가와 함께 유리전이온도 ($T_g$)가 상승하여 $0^{\circ}C$ 영역에서의 tan ${\delta}$ 값이 향상되었고, $60^{\circ}C$ 영역에서의 tan ${\delta}$ 값이 감소되었다. 초기 가교 속도 ($t_1$)는 $60^{\circ}C$의 tan ${\delta}$ 값과 선형적인 관계를 나타내었다. 이는 가교제의 증량으로 초기 가교 속도 ($t_1$)가 빨라져 조기에 가교가 시작됨으로써 filler network 의 발달을 억제시킨 결과에 따른 것으로 판단된다. 이러한 결과는 AFM (atomic force microscopy)을 통하여 열처리된 컴파운드의 표면 관찰에서도 확인할 수 있었다. 따라서, 빠른 초기 가황 반응에 기인한 실리카의 re-agglomeration 감소는 $60^{\circ}C$에서의 tan ${\delta}$를 결정하는 매우 중요한 변수임을 알 수 있다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권3호
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• pp.169-175
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• 1999

2,4-Dinitrophenol(DNP) is a metabolic uncoupler that prevents cells from creating energy for growth and it has been suggested that the availability of sodium ions may be important in mitigating the effects of uncouplers. Accordingly, the degradation of DNP was investigated using activated sludge which had been adapted to mineralize DNP. After the acclimation of the activated sludge, the effect of sodium ions on the toxicity of high concentrations(80 to 100mg/L) of DNP was investigated over a sodium ion concentration range of 9.3$\times$10-5 to 94mM. The concentration of sodium ions in the activated sludge mixed liquor seemed to have little effect on the DNP toxicity. However, a lack of sodium in the grwoth media resulted in a reduction of the DNP degradation rate by a bacterial isolate from the activated sludge culture identified as Nocardia asteroides.

• Elastomers and Composites
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• 제38권2호
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• pp.167-174
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• 2003

Thermoplastic vulcanizates (TPV) or dynamic vulcanizates are thermoplastic elastomers produced by simultaneous mixing and crosslinking of a rubber and a thermoplastic. The objective of the present work is to investigate the effects of different types of peroxides as curing agents on the properties of PP/EPDM TPVs. The mechanical properties change significantly with the chemical nature of the peroxides and the extent of crosslinking at a fixed PP/EPDM blend ratio. The tensile strength of the TPVs obtained with the various peroxides can be related to the solubility parameters of the polymers and of the peroxides. The Young's modulus of the peroxide-cured TPVs can be correlated with the delta torque values of equivalent thermoset EPDM vulcanizates, corresponding to the crosslinking efficiencies of the peroxides.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.627-634
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• 1997

This is the Study on Application and Manufacture Technique of Cold-Mix, Cold-Laid type Asphalt Concrete using of Polymer modified asphalt the could be constructed easily and economically on damaged road repaireless for seasons. The modified materials for this study are SBS(Styrene-Butadiene-Styrene). SBR (Styrene-Butadiene-Rubber) and PUR(Polyurethane). The Marshall stability and the value of flow and resistance in water stability degree according to the alternation types and weight percent of modified materials were compared and evaluated on this study. The results of the study show that PUR modified asphalt have improvement of over 150% Marshall stability in AI MS-14 standard and they are evaluated to have the easiness of storage and better working efficiency compared with other types of modified asphalt compound.

• 한국환경과학회지
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• 제16권7호
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• pp.779-784
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• 2007

Dinitrophenol is preventing cells from making energy for growth and it has been suggested that pH may be important in mitigating effects of uncouplers. The effect of pH on toxicity of dinitrophenol at high concentration was investigated, over a pH range of 5.7 to 8.7. DNP inhibition was found to be strongly dependent on mixed liquor pH. The DNP degradation rate was highest in the pH range of 7.0 to 7.8; at pH 6.0 degradation of 0.41 mM dinitrophenol was significantly inhibited; at pH <5.7, dinitrophenol degradation was completely inhibited after approximately 25% of the dinitrophenol was degraded. However no significant effect of pH variation was seen on glucose uptake by the activated sludge mixed culture.

• Elastomers and Composites
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• 제58권2호
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• pp.87-94
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• 2023

Abrasion tests of an SBR compound were conducted using four different types of abrasion testers (cut and chip, Lambourn, DIN, and LAT100). The abrasion test results were analyzed in terms of size distributions and morphologies of the wear particles. Most wear particles were larger than 1000 ㎛. The wear particle size distributions tended to decrease as the particle size decreased. Except for the Lambourn abrasion test, the wear particles smaller than 212 ㎛ were rarely generated by the other three abrasion tests, implying that small wear particles were produced through friction by introducing talc powder. Shapes of the wear particles varied depending on the abrasion testers. The wear particles generated from the Lambourn abrasion tester had stick-like shapes. The cut and chip abrasion test showed a clear abrasion pattern, but the DIN abrasion test did not show any specific abrasion pattern. The Lambourn and LAT100 abrasion tests showed irregular abrasion patterns.

• Elastomers and Composites
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• 제50권3호
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• pp.196-204
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• 2015

Crosslink density of a rubber vulcanizate determines the chemical and physical properties, while bound rubber is an important factor to estimate reinforcement of a filled rubber compound. Extender oil is added to a raw rubber with very high molecular weight for improving processability of a rubber composite. Influence of extender oil on crosslink density, bound rubber formation, and physical properties of solution styrene-butadiene rubber (SSBR) composites with differing microstructures was investigated. Crosslink densities of non-oil-extended SSBR (NO-SSBR) vulcanizates were higher than those of oil-extended SSBR (OE-SSBR) ones. Bound rubber contents of NO-SSBR compounds were also greater than those of OE-SSBR ones. The experimental results could be explained by interfering of extender oil. The OE-SSBR vulcanizates had low modulus but long elongation at break, whereas the NO-SSBR ones had high modulus but short elongation at break. It was found that the crosslink densities affected the physical properties more than the bound rubber contents. The moduli increased with increase in the crosslink density irrespective of extender oil, while the elongation at break decreased. Each variation of the tensile strengths of NO-SSBR and OE-SSBR vulcanizates with the crosslink density showed a decreasing trend. Tear strength of the OE-SSBR vulcanizate increased with increase in the crosslink density, whereas variation of the tear strength of NO-SSBR vulcanizate with the crosslink density showed a weak decreasing trend.