• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.811-815
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• 2003

The effects of high-range water-reducing agent (WRA) content and polymer-cement ratio on the strength properties of autoclaved SBR-modified mortars with WRA are examined. As a result, the flexural strength of the autoclaved SBR-modified mortars with WRAs tends to increase with increasing WRA content and polymer-cement ratio, and reaches a maximum at a WRA content of 2.0%. The compressive strength of the autoclaved SBR-modified mortars with WRAs is inclined to increase with increasing WRA content and polymer-cement ratio, and reaches a maximum at a WRA content of 2.0% and a polymer-cement ratio of 10%. From the test results, the addition of the WRAs is effective for improving strength properties of the autoclaved SBR-modified mortars.

• Elastomers and Composites
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• v.54 no.1
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• pp.54-60
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• 2019

The rapid development of the automobile industry is an important factor that led to the dramatic development of synthetic rubber. The tread part of tire that comes in direct contact with the road surface is related to the service life of the tire. Rubber compounds used in tire treads are often blended with SBR (styrene-butadiene rubber) and BR (butadiene rubber) to satisfy physical property requirements. However, when two or more kinds of rubber are blended, phase separation and silica dispersion problems may occur due to non-uniform mixing of the rubber. Therefore, in this study, we synthesized an SBR copolymer with the same composition as that of a typical SBR/BR blend compound by controlling butadiene content during ESBR (emulsion styrene-butadiene rubber) synthesis. Subsequently, silica filled compounds were manufactured using the synthesized ESBR, and their mechanical properties, dynamic viscoelasticity, and crosslinking density were compared with those of the SBR/BR blended compound. When the content of butadiene was increased in the silica filled compound, the cure rate accelerated due to an increased number of allylic positions, which typically exhibit higher reactivity. However, the T-2 compound with increased butadiene content by synthesis less likely to show an increase in crosslink density due to poor silica dispersion. In addition, the T-3 compound containing high cis BR content showed high crosslink density due to its monosulfide crosslinking structure. Because of the phase separation, SBR/BR blend compounds were easily broken and showed similar $M_{100%}$ and $M_{300%}$ values as those of other compounds despite their high crosslink density. However, the developed blend showed excellent abrasion resistance due to the high cis-1,4 butadiene content and low rolling resistance due to the high crosslink density.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.539-547
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• 2007

The effects of binder and alumina content on the setting time, drying shrinkage, strength, freezing and thawing resistance and water absorption of polymer-modified pastes with alumina powder were examined. As a result the setting time of the polymer-modified pastes with alumina powder tended to delay with increasing binder content. Irrespective of the type of polymer, the drying shrinkage of the polymer-modified pastes with alumina powder tended to decrease with increasing binder content and alumina powder content. Regardless of the type of polymer, the tensile and adhesion strengths of the polymer-modified pastes with alumina powder tended to increase with increasing binder content and alumina powder content. Irrespective of the type of polymer, the durability factors of the polymer-modified pastes with alumina powder tended to increase with increasing alumina content. Irrespective of the type of polymer, the water absorptions of the polymer-modified pastes with alumina powder tended to decrease with increasing binder content and alumina content.

• Elastomers and Composites
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• v.25 no.4
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• pp.280-290
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• 1990

The effect of surface treatment of kaolinite with silane coupling agent on the reinforcement of SBR was investigated. The possibility of the practical use of kaolinite as an organic filler was also scrutinized and it was found that the reinforcement of SBR was improved by modifying surface of the cheap inactive inorganic filler with organic silane coupling agents. 3-Chloropropyltrimethoxysilane(C-series), 3-mercaptopropyltrimethoxysilane(M-series) and 3-aminopropyltriethoxysilane(A-series) were used as coupling agents. To test the material properties of vulcanized and unvulcanized SBR, Mooney viscosity, modulus, elongation and fractured surface measurements by SEM were carried out by changing the amount of silane coupling agents. Torqe of the unvulcanized SBR following the measurement of the degree of vulcanization was to be increased as the amount of silane was increasing, and Mooney viscosity of M-series and A-series was also increased.

• Elastomers and Composites
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• v.6 no.1
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• pp.53-70
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• 1971

We have studied the blending effects of cis-1,4-polybutadiene (CBR) and styrene-tutadiene rubber at various blending ratios of 100 : 0, 70 30, 50 : 50, 30 : 70, 0 : 100, and of carbon black ISAF and HAP at various compounding ratios of 45 PHR, 55 PHR, 65 PHR, for tyre tread rubber. The results obtained are summerized as follows; 1. For tyre tread rubber, it was found to increased efficiency to use SBR polymer only than to use the blending ratio CB/SBR=30/70 below. But it was observed that the latter was adapted for the bus or truck tyre and the former for the passenger tyre. 2. Excellent efficiency was obtained in case of carbon black compounding ratio of 55%, and also the compounding of ISAF made better efficiency than that of HAF. 3. Carbon black was more efficient to SBR than to CB. 4. For the aging ratio, the compounding rubber of NR was the highest, and the ratio was decreased in order of the compounding rubber of oil-extended SBR or CB polymer only, the compounding rubber of non oil-extended SBR or CB polymer only, and the blending rubber.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.888-893
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• 2003

The purpose of this study is to make clear the durability of the polymer films formed in the autoclaved polymer-modified mortars and concretes. The polymer films prepared with polymer dispersions such as a styrene-butadiene rubber (SBR) latex, a poly (ethylene-vinyl acetate)(EVA) emulsion and a polyacrylic ester (PAE) emulsion for polymeric admixtures are exposed to autoclaving at 18$0^{\circ}C$ in temperature and 1.01 MPa in vapor pressure, and subjected to tensile test and infrared spectroscopy. The durability of the polymer films is evaluated from the application of autoclaving to the polymer films under saturated Ca(OH)$_2$ solution immersion causes no degradation for SBR films and a significant degradation due to the saponification of the polymers for EVA and PAE films. Accordingly, in the application of autoclaving to polymer-modified mortars and concretes, it is suggested that SBR-modified mortars and concretes are hardly degraded but EVA- and PAE-modified mortars and concretes are markedly degraded by the saponification of the polymers.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.84-92
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• 1996

The flexural and compressive strengths of polymer-modified mortars containing FRP wastes were investigated. The specimens of polymer-modified mortars containing FRP mortat were perpared by using styrene-butadiene rubber(SBR) latex, ethylene-vinyl acetate(EVA) emulsion and polyacrylic ester(PAE) emulsion with various FRP-sand ratios(10, 20, 30, 40, 50wt%). The compressive and flexural strengths of polymer-mokified mortars containing FRP wastes were decreased with an increase of FRP-sand ratio. But the compressive and flexural strengths of PAE polymer-modified mortar were more improved than OPC, whereas those of SBR and EVA polymer-modified mortars containing FRP wastes were decreased than OPC.

• Elastomers and Composites
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• v.22 no.1
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• pp.11-19
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• 1987

A coil pyrolyzer and processor-controlled gas chromatograph were used for analysis of rubber for compounding ratio of the single and blend rubber vlucanizates. Variables such as sample size, pyrolysis temperature, time allowed for pyrolysis, the column packing material, its length and programmable temperature for gas chromatography were examined to obtain optimum condition for application to NR, BR and SBR blends. By application fixed conditions, three kinds of standard curves were finally obtained from thirty samples of blend vulcanizates which were prepared in the pilot plant, NIRI. It is possible to determine rubber composition and their ratio in NR, BR and SBR products by pyrolysis.

• Macromolecular Research
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• v.9 no.1
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• pp.45-50
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• 2001

Formation of bound rubber depends on the filler-polymer interactions including physical adsorption, chemisorption, and mechanical interaction. Bound rubbers consist of tightly and loosely bound ones. Styrene-butadiene rubber (SBR) is composed of styrene, 1,2-, cis-1,4-, and trans-1,4-units. Filler-polymer interactions of each components of SBR with fillers, carbon black and silica, were studied by analysis of microstructure of the bound rubber. Filler-polymer interaction of the 1,2-unit with the fillers was found to be stronger than those of the other components and this phenomenon was shown more clearly in the tightly bound rubber.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.190-198
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• 2002

In this research the physical properties of polymer modified mortar containing pulverized FRP(Fiber-Reinforced Plastics) wastes fine powder as a part of fine aggregate were investigated. Styrene-butadiene rubber(SBR) latex, polyacrylic ester(PAE) emulsion and ethylene-vinyl acetate(EVA) emulsion were used as Polymer modifier. Polymer modified mortars containing FRP wastes fine powder were prepared with various FRP wastes fine powder replacement(5∼30 wt％) for fine aggregate and polymer-cement ratios(5∼20 wt％). The water-cement ratio, water absorption rates and hot water immersion test, compressive and flexural strengths of polymer modified mortars were tested and the results compared to those of ordinary portland cement mortar. As the results, compressive and flexural strengths of polymer modified mortar containing FRP wastes fine powder depend on the contents of FRP wastes fine powder, type and additional amounts of polymer modifier. Some of them showed higher compressive and flexural strengths than those of ordinary portland cement mortar. Especially, SBR-modified mortar showed the highest strengths properties among three types of polymer modifier. Also water absorption rates, compressive and flexural strengths of SBR-modified mortar were more superior than those of PAE or EVA-modified mortar. The optimum mix proportions of SBR-modified mortar was 20 wt％ of polymer-cement ratio and 20 wt％ of FRP wastes fine powder replacement. Otherwise heat cured polymer modified mortar accelerated the improvement of early compressive and flexural strengths.