• Elastomers and Composites
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• 제53권3호
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• pp.168-174
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• 2018

Natural rubber (NR) and bromo-isobutylene-isoprene rubber (BIIR) were compounded with other formulation chemicals through polymer blending via a mechanical mixing method. After rubber vulcanization by hot-press compression molding, the cure characteristics, mechanical properties, and ozone resistance of the NR/BIIR blends were measured. As the BIIR content increased, the maximum torque of the blends decreased, while the optimum cure time and scorch time tended to increase. Furthermore, the hardness of the blends increased with increasing BIIR content, reaching the maximum value at 75 wt% BIIR, and decreased with a further increase in the BIIR loading. The tensile strength and elongation at break decreased with an increase in the BIIR content, reaching the minimum value at 75 wt% BIIR, and increased with a further increase in the BIIR content. In the ozone resistance test, cracks were not generated when the BIIR content was more than 75 wt%.

• Bulletin of the Korean Chemical Society
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• 제15권12호
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• pp.1064-1069
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• 1994

Chlorobis(isoprene)rhodium(Ⅰ) (3), prepared by olefin-exchange reaction of chlorobis(cyclooctene)rhodium dimer (2) with isoprene, reacted with benzaldimine 4 to give iminoacylrhodium(Ⅲ) ${\eta}^3$-1,2-dimethylallyl complex 6. Ligand-promoted reductive elimination of 6 by pyridine and P(OMe)$_3$ produced ${\beta},{\gamma}$-unsaturated ketimine 8, which was readily hydrolyzed to give ${\beta},{\gamma}$-unsaturated ketone 9. Other methyl branched dienes such as 2,3-dimethylbutadiene, 3-methyl-1,3-pentadiene, 2-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3-methyl-1,4-pentadiene and 2-methyl-1,4-pentadiene, were applied the synthesis of ${\beta},{\gamma}$-unsaturated ketones. In case of 2,4-dimethyl-1,3-pentadiene, only ${\gamma},{\delta}$ -unsaturated ketone 25, 1,2-addition product, was obtained, may be due to the mono-olefin coordination.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2009년도 추계학술대회 논문집
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• pp.277-279
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• 2009

• 한국환경과학회지
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• 제24권2호
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• pp.207-219
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• 2015

The purpose of this study is to show the geographical distribution and the temporal variation of the emission amount of biogenic volatile organic compounds(BVOCs) emanated from forests at Jeju Island. The total emission amount of BVOCs calculated by using the CORINAIR Methodology is $3612ton\;yr^{-1}$ at Jeju Island. More than half of BVOCs emissions is come from coniferous forest, and 45 per cent from broad leaved forest. The others is attributed to grassland. Of total emission of BVOCs, isoprene accounts for 28 per cent, monoterpene for 32 per cent, and other VOCs for about 40 percent, respectively. It can be shown that $3000{\sim}10000kg\;yr^{-1}$ of BVOCs is emitted at the zone with dense forest from an altitude of 500 m to the top of Mt. Halla, and less than $1500kg\;yr^{-1}$ at the zone an altitude of below 500 meters. The monoterpene emission is more than $1500kg\;yr^{-1}$ due to the existence of a colony of Abies koreana at the place with more than 1500 meters and a community of Pinus thunbergii and Cryptomeria japonica at the elevation of 500~700 m. In the case of isoprene emission, there is $1500{\sim}3000kg\;yr^{-1}$ at the zone of an elevation from 700 m to 1500 m due to dense broad leaved forest and very little of its emission at an elevation of more than 1500 meters because there is hardly broad leaved trees grown. In this study, emission of BVOCs according to the altitude above sea level is estimated under the situation of lack of the data for broad leaved tree. More detailed data and information for the distribution of broad leaved trees are needed in order to calculate more realistic BVOC emission.

• Elastomers and Composites
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• 제38권4호
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• pp.326-333
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• 2003

Dynamic DSC 방법을 이용하여 isoprene(IR) 및 chloroprene(CR) 고무로 개질된 NR/CB 고무 복합체의 가황반응을 연구하였다. 각각의 샘플에 대하여 승온속도를 달리한 열분석 곡선을 얻었고 이로부터 Kissinger의 해석 방법에 따라 가교반응 기구를 연구하였다. 실험에 사용된 고무 복합재료는 대개 $120{\sim}180^{\circ}C$ 사이의 온도영역에서 가교 반응이 일어나는 것이 확인되었으며, 승온속도가 $3^{\circ}C/min$에서 $30^{\circ}C/min$로 빨라질수록 최대반응 속도점의 온도($T_p$)는 점점 높은 쪽으로 이동하였고, 반응 발열량도 상대적으로 커지는 것으로 관찰되었다. Kissinger의 해석방법을 이용하여 실험 데이터를 분석한 결과, 실험에 사용된 샘플의 가교반응은 1차반응에 의해 진행되는 것으로 밝혀졌으며 개질제로서 사용된 고무 중에서 IR을 사용한 경우보다는 CR을 개질제로 사용한 경우에 반응온도에 상대적으로 더 민감한 것으로 판명되었다. 그러나 충전제로 사용된 카본블랙의 경우에는 종류와는 무관하게 반응기구에는 거의 영향을 미치지 않는 것으로 밝혀졌다.

• Elastomers and Composites
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• 제53권3호
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• pp.158-167
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• 2018

In this study, in-situ trans-selective polymerization of isoprene was carried out using titanium-based Ziegler-Natta catalysts. The catalysts were prepared by high-energy ball milling. Individually Large-inner-diameter carbon nanotubes (CNTL), and hydroxylated carbon nanotubes (CNTOH), along with magnesium chloride ($MgCl_2$) were used as the carriers for the catalysts. The optimum ball-milling time for preparing the $CNT/MgCl_2/TiCl_4$ Ziegler-Natta catalysts was 4 h. The $CNTOH/MgCl_2/TiCl_4$ catalyst showed a higher efficiency than that of the $CNTL/MgCl_2/TiCl_4$ catalyst, based on the rate of polymerization. The effects of the CNT-filler type on the isoprene polymerization behaviors and polymer properties were investigated. The morphologies of the trans-1,4-polyisoprene (TPI)/CNT and TPI/CNTOH nanocomposites exhibited a tube-like shape, and the CNTL and CNTOH fillers were well dispersed in the TPI matrix. In addition, the thermal stability of TPI significantly increased upon the introduction of a small amount of both CNTL/CNTOH fillers (0.15 wt%), owing to the satisfactory dispersion of the CNTL/CNTOH in the TPI matrix.

• 한국환경과학회지
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• 제16권3호
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• pp.269-275
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• 2007

The standard emission rate(ERs) of isoprene was quantitatively measured in situ from Quercus mongolica Fischer that dominates more than about 85% of domestic oak trees. The ERs values in spring and summer were similar to 64.4 and 58.1 (${\mu}gC/gdw/hr$), respectively. The ERs in autumn, 7.06(${\mu}gC/gdw/hr$), was about $8{\sim}9$ times lower than those in spring and summer. The coefficient of determination ($r^2$) between ERs and $C_L\;C_T$ ranged from 0.593 to 0.836. The correlation coefficients between the ERs and PAR. the ER and temperature suggested that ERs have strong correlation with PAR(photosynthetically active radiation) and temperature. In addition, the high values of PAR, temperature, and ERs were found in the time zone of $15:00{\sim}17:00$(spring), $15:00{\sim}16:00$(summer), and $14:00{\sim}15:00$(autumn).

• 한국산학기술학회논문지
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• 제9권6호
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• pp.1787-1794
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• 2008

Coenzyme $Q_{10}$과 그 유도체 coenzyme $Q_n$ 6종을 합성하고, 이들 유도체에 대하여 상피세포(LLC-PK1 cell)를 이용한 항산화 효과와 NIH/3T3 세포를 이용한 세포독성 실험을 실시하였다. 그 결과, 합성한 coenzyme $Q_n$ 유도체들이 coenzyme $Q_{10}$에 비해 우수한 항산화 효과를 나타내었으며, 그 중 coenzyme $Q_3$-C가 모든 농도에서 $107.7{\sim}135.9%$로 가장 우수한 효과를 나타내었다. 또한, 모든 coenzyme $Q_n$ 유도체들이 Coenzyme $Q_{10}$과 유사한 세포독성을 나타내었다. Coenzyme $Q_n$의 n수에 따른 항산화 효과 및 세포독성 실험에서 isoprene unit의 수가 적은 유도체들에서 우수한 효과를 나타내었다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2000년도 정기총회 및 봄 학술발표회
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• pp.239-240
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• 2000

열건조식 음식물쓰레기 처리기에서 발생하는 VOC의 분해효율을 향상시키기 위하여 생물여과기를 이용하여 실험하였다. 현장 생물여과기에서 배출되는 휘발성 물질은 총 50여 가지 물질이 검출되었다. 주요 악취 유발물질은 isoprene, dimethyl sulfide (DMS), dimethyl disulfide (DMDS), limonene 등으로 파악되었다. 칼럼 반응기를 이용한 휘발성 물질 분해는 20일 정도의 적응기 후 제거되었으며, 제거 효율은 90% 이상으로 나타났다.

• 한국연초학회지
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• 제26권2호
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• pp.179-185
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• 2004

This study was conducted to investigate the delivery pattern of volatile organic compounds(VOCs) in mainstream smoke generated by the combustion of a different ventilated cigarette. To compare the delivery pattern and the concentration of VOCs in mainstream smoke, the six different ventilated cigarette was manufactured and analyzed VOCs using the GC/MS. As a result of this experiments, cambridge filter used to trap the particulate matter in mainstream smoke did not affect on the trapping of VOCs components, and two impinger method among the trapping methods was the best condition to trap VOCs from mainstream smoke. As the slope of the delivery of VOCs such as isoprene, acrylonitrile and toluene were higher than 1, but that of benzene was lower than other VOCs.