• Elastomers and Composites
• /
• v.38 no.1
• /
• pp.65-71
• /
• 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.

• Elastomers and Composites
• /
• v.41 no.1
• /
• pp.10-18
• /
• 2006

Influence of low molecular weight polybutadiene (liquid PB) treated with maleic anhydride on properties of a silica-filled SBR compounds was studied. Silica dispersion was improved by adding liquid PB. The liquid PB treated with maleic anhydride (liquid MAPB) was found to be more effective for the improvement of silica dispersion than the liquid PB without maleic anhydride (liquid NPB). Viscosity of the SBR compound decreased by adding the liquid PB. The crosslink density decreased with increase of the liquid PB content and the cure rate became slower with increasing the liquid PB content. Considering the experimental results, it was believed that addition of small amount of the liquid PB (less than 5 phr) was desirable to improve properties of silica-filled SBR compounds.

• Journal of Korean Society on Water Environment
• /
• v.24 no.3
• /
• pp.340-344
• /
• 2008

Electro-flotation (EF) was applied to a sequencing batch reactor process (SBR) in order to enhance solids-liquid separation. Solids-liquid separation was good enough in the SBR coupled with EF (EF-SBR) and it was possible to maintain the concentration of mixed liquor suspended solids (MLSS) high in the EF-SBR. Under moderate organic loading condition (COD loading rate: 6 g/day), control SBR (C-SBR) showed similar treatment efficiencies with the EF-SBR. Under high organic loading condition (COD loading rate: 9.6 g/day), the solids-liquid separation in the C-SBR was deteriorated due to proliferation of filamentous bulking organisms at high F/M ratio. However, the EF-SBR was operated stably and with the high MLSS concentration (above 4,000 mg/L) regardless of the organic loading conditions during overall operating period leading to the satisfactory effluent quality. Gas production rate of the electrodes was gradually decreased because of anodic corrosion and scale build-up at the surface of cathode. However it could be partially overcome by use of corrosion-proof electrode material (SUS-316 L) and by periodic current switching between the electrodes.

• Environmental Engineering Research
• /
• v.19 no.4
• /
• pp.395-399
• /
• 2014

Operation characteristics of the sequencing batch reactor (SBR) process with electro-flotation (EF) as a solid liquid separation method (EF-SBR) were investigated. EF-SBR process showed excellent solid-liquid separation performance which enabled to separate biosolids from liquid phase within 30 min and to extend cyclic reaction time. Although influent organic loading rate was increased stepwise from 5 to 15 g COD/day, food to microorganisms (F/M) ratio could be maintained about 0.3 g COD/g VSS/day in EF-SBR because biomass concentration could be easily controlled at desired level by EF. However, it was impossible to increase biomass concentration at the same level in control SBR (C-SBR) process because solid-liquid separation by gravity settling showed a limitation at higher mixed liquor suspended solids (MLSS) concentration with 60 min of settling time. Total chemical oxygen demand (TCOD) removal efficiency of EF-SBR process was not decreased although influent organic loading rate became 3 times higher than initial value. However, it was seriously deteriorated in C-SBR process after increasing the rate over 10 g COD/day, which was accounted for insufficient organic removal by relatively higher food to microorganisms (F/M) ratio as well as biosolids wash-out by a limitation of gravity sedimentation.

• Elastomers and Composites
• /
• v.36 no.3
• /
• pp.162-168
• /
• 2001

Low molecular weight polybutadiene (liquid BR) improves the filler dispersion in a silica-filled styrene-butadiene rubber (SBR) compound. In the present work, influence of molecular weight or the liquid BR on properties of a silica-filled SBR compound was studied. Minimum and maximum torques in the rheocurve for the compound containing the liquid BR with higher molecular weight (HLBR) are lower than those for the compound containing the liquid BR with lower one (LLBR) while the delta torques are nearly the same. Mooney scorch time of the compound containing HLBR is faster than that of the compound containing LLBR. Modulus or the compound containing HLBR is lower than that of the compound containing LLBR while tensile strength of the former is higher than that of the latter. The elongation at break of the former is also longer than that of the latter. Stability for the thermal aging at $90^{\circ}C$ for 3 days is less favorable for the former than for the latter.

• Journal of Animal Environmental Science
• /
• v.14 no.2
• /
• pp.113-118
• /
• 2008

Sequencing batch operation consists of fill, react, settle and decant phases in the same reactor. Operation consists of anaerobic, anoxic and oxic (aerobic) phases when nutrient removal from the wastewater is desired. Since the same reactor is used for biological oxidation (or mixing) and sedimentation in aerobic and anaerobic SBR operations, capital and operating costs are lower than conventional activated sludge process and conventional anaerobic digestion process, respectively. Therefore, Aerobic SBR and Anaerobic SBR operations may be more advantageous far treatment of small volume animal wastewater in rural areas.

• Polymer(Korea)
• /
• v.25 no.5
• /
• pp.625-634
• /
• 2001

New polymeric photostabilizers containing hindered amine light stabilizer (HALS) were prepared by the reaction of liquid polyisoprene rubber grafted maleic anhydride (MAH) and 2,2,5,6-tetramethyl-4-piperidinol (TMPO). Their chemical composition and physical properties were characterized by titration, GPC and TGA analysis. The effects of polymeric HALS on the photooxidation of the styrene-butadiene rubber were studied from the UV, IR spectral changes, and photo-crosslinking was examined by the measurement of the insoluble fraction. The photooxidation of SBR upon irradiation was inhibited by addition of the new polymeric HALS. The extraction resistance of new polymeric photostabilizer was much better than that of the low molecular weight compound which is prepared by the reaction of MAH and TMPO. The new polymeric HALS ate fairly compatible with the SBR.

• Elastomers and Composites
• /
• v.55 no.1
• /
• pp.26-39
• /
• 2020

The physical properties of silica-filled SBR compounds (WSBR) prepared using silica-SBR wet masterbatches (WMB) were systematically investigated to understand the effect of the surface treatment of silica on the reinforcement performance of SBR. Treatment of silica with bis(triethoxysilylpropyl)tetrasulfide (TESPT) in the liquid phase, followed by mixing with an SBR solution and recovery by water stripping, easily produced silica-SBR WMB. However, insufficient surface treatment in terms of the amount and stability of the incorporated TESPT led to considerable silica loss and inevitable TESPT elution. Pretreatment of silica in the gas phase with TESPT and another organic material that enabled the formation of organic networks among the silica particles on the surface provided hydrophobated silica, which could be used to produce silica-SBR WMB, in high yields of above 99%. The amount and type of organic material incorporated into silica greatly influenced the cure characteristics, processability, and tensile and dynamic properties of the WSBR compounds. The TESPT and organic material stably incorporated into silica increased their viscosity, while the organic networks dispersed on the silica surface were highly beneficial for reducing their rolling resistance. Excessive dosing of TESTP induced low viscosity and a high modulus. The presence of connection bonds formed by the reaction of glycidyloxy groups with amine groups on the silica surface resulted in physical entanglement of the rubber chains with the bonds in the WSBR compounds, leading to low rolling resistance without sacrificing the mechanical properties. Mixing of the hydrophobated silica with a rubber solution in the liquid phase improved the silica dispersion of WSBR compounds, as confirmed by their low Payne effect, and preservation of the low modulus enhanced the degree of entanglement.

• Journal of the Korean Chemical Society
• /
• v.7 no.2
• /
• pp.115-121
• /
• 1963

Aliphatic hydrocarbon gases from rubber pyrolysis have been identified by gas chromatography with tetraethyleneglycol dimethylether column. Rubbers used in this work are polyisoprene, SBR, NBR, polybutadiene, buthyl rubber, polychloroprene and polyurethane rubber. The chromatogram is characteristic for each polymer. Author proposes a method of identification of synthetic rubbers by gas chromatograph of pyrolyzed gas. Sample is pyrolyzed at $450^{\circ}C$ under nitrogen or more effectively helium and gaseous portion, which eliminated liquid condensate, is passed to the column. The appearance of exclusively large peak of isoprene, isobutylene and carbon dioxide shows the presence of polyisoprene, polyisobutylene and polyurethane, respectively. Large peak of butadiene will appear in case of polybutadiene, SBR and NBR, but SBR can be identified through the styrene peak in gas chromatogram of liquid pyrolyzate and NBR can be identified by the evolution of hydrogen cyanide during pyrolysis. Polychloroprene is identified by the evolution of hydrogen chloride. This method could be applied to the identification of copolymer or polymer blend.

• Elastomers and Composites
• /
• v.34 no.5
• /
• pp.414-422
• /
• 1999

SBR, polyurethane and epoxy latex were separately blended with ethylene-vinyl acetate(EVA) emulsion In $0{\sim}50%$. EVA emulsion was not reacted with latexes in liquid phase and mixtures had good stroage stability. The viscosity of cement mixtures was elevated to 20,000cps in $0.5{\sim}2.0$ hours by mixing. The mixtures mixed with pigment represented high viscosity and showed higher viscosity as time goes by. Mixtures had higher hardness with mixing SBR than mixing epoxy or urethane. The hardness was suddenly increased over cement content 30%. showed pencil hardness $H{\sim}2H$ in $50{\sim}60%$. The increase of hardness in high solids was depended upon not only the condensation of latexs but also the coagulation and adhesion of cement particle.