• Title, Summary, Keyword: SBR

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Low Molecular Weight SBR Effect on Properties of Silica-Filled SBR Compounds (저분자량 SBR이 실리카로 보강된 SBR 배합물의 특성에 미치는 영향)

  • Park, Byung-Ho;Hong, Seong-Uk;Choi, Sung-Seen
    • Elastomers and Composites
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    • v.38 no.1
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    • pp.65-71
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    • 2003
  • Influence of low molecular weight styrene-butadiene rubber (liquid SBR) on properties of a silica-filled styrene-butadiene rubber (SBR) compounds was studied. Viscosity of the silica-filled SBR compound decreased by adding the liquid SBR. The crosslink density decreased and the cure rate became slower as the liquid SBR content increased. The modulus and tensile strength decreased while the elongation at break became longer by increasing the liquid SBR content. The abrasion losses were nearly the same irrespective of the liquid SBR content. This might be due to the improvement of silica dispersion by adding the liquid SBR. Considering the experimental results, it was believed that addition of small amount of the liquid SBR (less than 5 phr) was desirable to improve properties of silica-filled SBR compounds.

Nitrogen Removal Characteristics in Two-Sludge System of SBR Type Using Sewage Wastewater of Low C/N Ratio (낮은 C/N 비에서 운영되는 SBR 유형의 Two-Sludge 공정의 질소 제거 특성)

  • Ryu, Hong-Duck;Kim, Hak-In;Lee, Sang-Ill
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.1
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    • pp.7-14
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    • 2006
  • In this study, nitrogen removal characteristics of SBR3 process, which is two-sludge system of sequencing batch reactor(SBR) type, were investigated, with comparison of those of SBR1 process, which is conventional SBR process, and SBR2 process, which was designed to enhance denitrification efficiency through step-feeding of wastewater, using domestic wastewater. SBR3 process of two-sludge type can perform external nitrification, on which nitrification occurs in separated reactor, and enhanced denitrification using biosorbed organics. In the results with domestic wastewater, T-N removal efficiency of SBR3 process was better than those of SBR1 and SBR2 processes. It was observed that bigger difference of T-N removal efficiency between SBR3 process and SBR1 & SBR2 processes was showed at low C/N ratio than that at high C/N ratio resulting from more efficient use of organics by biosorption mechanism in denitrification of SBR3 process than those of SBR1 and SBR2 processes. In addition, T-N removal efficiency of SBR3 process according to influent T-N loading rate was better than those of SBR1 and SBR2, even though influent T-N loading rate of SBR3 process was higher than that of SBR1 and SBR2 process resulting from operation of SBR3 process in short hydraulic retention time(HRT) by external nitrification.

Influence of Microstructure and Extender Oil on Cure Characteristics of Solution SBR Compounds

  • Ko, Eunah;Choi, Sung-Seen
    • Elastomers and Composites
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    • v.50 no.2
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    • pp.87-91
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    • 2015
  • Cure characteristics of non-oil-extended solution SBR (S-SBR_NO) and oil-extended solution SBR (S-SBR_ EO) compounds reinforced with silica/carbon black were investigated. Minimum and maximum torques of S-SBR_ EO compounds were much smaller than those of S-SBR_NO ones. Delta torques of S-SBR_NO compounds were greater than those of S-SBR_EO ones, and that of S-SBR_NO compound increased with increase in the 1,2-unit content. Optimum cure time ($t_{90}$) of S-SBR compound decreased with increase in the 1,4-unit content, whereas it increased with increase in the 1,2-unit content. Cure rate index of S-SBR compound increased with increase in the 1,4-unit content, whereas it decreased with increase in the 1,2-unit content. Comparing cure characteristics of S-SBR_NO and S-SBR_EO compounds with the same 1,2-unit content, $t_{90}$s of S-SBR_EO compounds were longer than those of S-SBR_NO ones and cure rate indices of S-SBR_EO compounds were smaller than those of S-SBR_NO ones.

Process variations in SBR and BS-SBR treatment (SBR 및 BS-SBR 처리의 공정변화 연구)

  • 양형재;정윤철;신응배
    • Journal of environmental and Sanitary engineering
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    • v.12 no.1
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    • pp.59-68
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    • 1997
  • The main purpose of this study was to determine effects of BS-SBR compared with SBR on the removal of soluble organics and sludge separation. In the BS-SBR process, soluble organics were removed by suspended activated sludge as well as biological fixed films and these two processes occurred simultaneously in one tank. The removal efficiency of soluble COD in the BS-SBR, approximately 97% in both 1 and 3-cycle/d was higher than for SBR. The BS-SBR process was very efficient for SS removal. The averaged SS concentration were 4.8 mg/l over the operation period, the daily SS values were consistently below 10 mg/l in both of 1-cycle and 3-cycle a day. The sludge settling characteristics in BS-SBR were totally different from SBR's. The sludge, dark brown, was well flocculated and its floc size was visible larger than the SBR's.

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Mechanical Properties of Acrylonitrile Functionalized Emulsion SBR/silica Compounds (아크릴로니트릴이 극성기로 도입된 유화중합 SBR/실리카 컴파운드의 기계적 물성)

  • Kim, Dong-Won;Seo, Byeong-Ho;Kim, Hee-Jeong;Paik, Hyun-Jong;Kang, Jong-Won;Kim, Won-Ho
    • Elastomers and Composites
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    • v.47 no.1
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    • pp.54-64
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    • 2012
  • Acrylonitrile was introduced in the emulsion SBR to increase compatibility between silica and rubber. AN-SBR/silica compounds showed faster vulcanization time and higher delta torque values than SBR 1721/silica compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface could make hydrogen bond that prevented adsorption of the accelerator on the silica surface, which improved the vulcanization reaction efficiency and enhanced the degree of crosslinking. AN-SBR/silica compound showed higher values in minimum torque than SBR 1721/silica compound during the vulcanization because AN-SBR has higher molecular weight than SBR 1721 in the raw material. When PEG was added to the SBR 1721 and AN-SBR compounds, vulcanization time was faster than SBR 1721 and AN-SBR compounds without PEG because PEG has a large number of ether linkages which show high compatibility with silanol group on the silica surface that prevented the adsorption of the accelerator and the ingredients on the silica surface, which improved the vulcanization reaction efficiency. In the mechanical properties, AN-SBR compounds showed higher modulus values at 100%, 300% than SBR 1721 compounds because interaction between nitrile group of AN-SBR and silanol group on the silica surface enhanced the degree of crosslinking. In the dynamic properties, AN-SBR compounds showed lower tan ${\delta}$ values at $0^{\circ}C$ than SBR 1721 compounds in accordance with the $T_g$ values. AN-SBR compounds showed lower tan ${\delta}$ values at $60^{\circ}C$ than SBR 1721 compounds because interaction between acrylonitrile and silica caused strong filler-rubber interaction that induced low energy dissipation by the filler-filler interaction.

Cure characteristics, Mechanical Properties and Ozone Resistance of EPDM/SBR Blend Vulcanizates (EPDM/SBR 블렌드 가황체의 경화특성, 기계적 성질 및 내오존성)

  • Park, Chan-Young
    • Elastomers and Composites
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    • v.43 no.2
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    • pp.104-112
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    • 2008
  • The ethylene propylene diene terpolymer (EPDM) blends with styrene butadiene rubber (SBR) were prepared from an open 2-roll mill following the conventional rubber blend method, and then cure characteristics, mechanical properties and ozone resistance were subsequently examined. With incorporation of SBR the torque value of the EPDM and SBR blends showed a gradual increase in the cure curve. The maximum torque value was obtained with lowest level at 25wt% of SBR and it was increased linearly with more than 25wt%. As the SBR loading increased scorch time and optimum cure time decreased. Hardness represented a maximum at 50wt% of SBR. However upper and lower than that value it decreased. It was found that the unfavorable characteristics of ozone resistance of pure SBR was significantly improved through the blending of SBR with EPDM.

Vulcanization and Mechanical Properties of High Molecular Weight Slyrene-Butadiene Rubber/Low Molecular weight Styrene-Butadiene Rubber Mixtures (고분자량 스티렌-부타디엔 고무와 저분자량 스티렌-부타디엔 고무 혼합물의 가황과 기계적 물성)

  • Lee, Hwa-Woo;Kim, Byeong-Cheol;Hong, Suk-Pyo;Lee, Dai-Soo
    • Elastomers and Composites
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    • v.34 no.2
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    • pp.121-127
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    • 1999
  • Characteristics of high molecular weight styrene-butadiene rubber(HM-SBR)/low molecular weight styrene-butadiene rubber(LM-SBR) mixtures were studied to investigate how to modify the processability and the mechanical properties of styrene-butadiene rubber (SBR). Mooney viscosity of the HM-SBR/LM-SBR mixtures and torque increase due to the vulcanization decreased by increasing the LM-SBR content of the mixtures. Shore A hardness and rebound properties were decreased by increasing the LM-SBR content of the mixtures. It was found that the value of tan ${\delta}$ of the mixtures in rubbery state was increased, while glass transition temperatures of the vulcanized blends were constant by increasing the LM-SBR content of the mixtures. It was postulated that the decrease of Mooney viscosity by increasing the LM-SBR content of the blends was due to plasticizing effects of the LM-SBR and the increased polydispersity of the mixtures. Change of mechanical properties of the vulcanized HM-SBR/LM-SBR mixtures was attributed to the decreased crosslink densities of the mixtures by increasing the LM-SBR content of the mixtures.

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Effects of Chemical Surface Modification of Carbon Black on Vulcanization and Mechanical Properties of Styrene-Butadiene Rubber Compound (SBR 컴파운드의 가황 및 기계적 성질에 미치는 카본블랙 표면의 화학적 개질의 영향)

  • Rhee, John-M.;Kim, Wan-Doo;Kaang, Shin-Young;Chang, Young-Wook;Park, Soo-Jin;Nah, Chong-Woon
    • Elastomers and Composites
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    • v.36 no.1
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    • pp.44-51
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    • 2001
  • To see the effect of chemical surface modification, the carbon black surfaces were treated with three types of chemicals (KOH, $H_3PO_4$, and benzene). Vulcanization and mechanical properties of a styrene-butadiene rubber (SBR) were investigated depending on the chemical treatments. The surface free energy increased considerably with the treatments by both the acid (HCB) and base (KCB), but only a slight increase was observed for benzene treatment(BCB). The BCB showed the highest level of the London dispersive component. The vulcanization reaction was found to be faster in the order of KCB-SBR> BCB-SBR> VCB-SBR(virgin) > HCB-SBR. The difference in minimum and maximum torque of rheocurve, representing the degree of crosslinking, was found to be higher for the BCB-SBR compared to those of VCB-SBR, KCB-SBR, and HCB-SBR. The BCB-SBR and KCB-SBR showed the improved tensile and dynamic mechanical properties. A linear relationship was found to exist between the London dispersive component of surface free energy and mechanical properties.

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Estimation of Nutrient Removal Efficiency and Phase Conversion Rate of Single Reactor SBR and SBR with Flexible Vertical (단일 및 가변형 SBR 공법의 영양염류 처리효율 및 "상"전환속도 평가)

  • Kim, Man-Soo;Park, Jong-Woon;Park, Chul-Whi;Lee, Sang-Ill
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.11
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    • pp.1215-1221
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    • 2005
  • The purpose of this research was to compare the nutrient removal efficiency, and to estimate the net reaction time in order to calculate a "phase" transfer rate. SBR(SBR1) with flexible verticals and single reactor SBR(SBR1). Consequently, the removal efficiencies of $COD_{Cr}$, and $BOD_5$ in SBR1 and SBR2 were 91.5%, 97.5% and 90.4%, 97.3%, Respectively. Accordingly, the organic removal efficiency was not distinguished in both processes. In the T-N and T-P removal efficiencies, however, SBR1 obtained higher removal efficiency than SBR2, at 12.1% and 7.6% respectively. Also, in the experiment to estimate the "phase" transfer rate, SBR1 was higher than SBR2 Because SBR1 has two phases in the single reactor simultaneously, it has the buffer capacity to reduce the "phase" transfer time and provides a definite reaction condition.

Enhancement of SBR for Speech Signal Using Adaptive Noise Floor Level (가변 잡음 레벨을 이용한 음성신호에 대한 SBR 성능 항상 기술)

  • Lee, Se-Won;Oh, Seoung-Jun;Ahn, Chang-Beom;Lee, Tae-Jin;Kang, Kyoung-Ok;Park, Ho-Chong
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.2
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    • pp.148-154
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    • 2009
  • In audio coding, SBR technology synthesizes the high-bands using patched time-frequency information from low-bands and the correction parameters, Since SBR transmits only correction parameters for high-bands, it provides a low-rate coding of high-bands, and is used as a core module of MPEG-4 HE-AAC, SBR was originally designed for audio signal and its performance for speech signal tends to decrease, and the major reason is an excessive noise floor in high-bands which is caused by incorrect tonality computation, In this paper, a new method to determine noise floor level in an adaptive fashion according to the speech characteristics is proposed in order to solve the problem of SBR for speech signal, The proposed method maintains the compatibility with the standard SBR, and the subjective performance evaluation shows that the proposed method improves the SBR performance especially for male speech signal compared with the standard SBR.