• Elastomers and Composites
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• 제34권2호
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• pp.147-155
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• 1999

고무와 혼합된 왁스는 고무 표면으로 이동하여 방어막을 형성한다. 일반적으로 고무의 오존화를 방지하기 위해 오존노화방지제를 왁스와 함께 사용하고 있다. 다양한 종류의 왁스가 첨가된 천연고무 가류물을 이용하여 왁스막이 오존노화방지제의 이동에 미치는 영향을 연구하였다 오존노화방지제로 IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), HPPD (N-l,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), SBPPD (N,N'-di(sec-butyl)-p-phenylenediamine), 그리고 DMPPD (N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine)를 사용하였다. 노화방지제 이동 실험은 $60^{\circ}C$ 와 $80^{\circ}C$에서 10, 20, 30일간 실시하였다. 노화방지제의 이동속도는 고무가류물에 왁스가 없을 때가 있을 때보다 빨랐으며 분자량이 큰 왁스가 혼합되었을 때가 분자량이 작은 왁스가 혼합되었을 때보다 느렸다. DMPPD와 SBPPD의 이동속도가 HPPD와 IPPD의 이동속도보다 빨랐다.

• Elastomers and Composites
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• 제33권1호
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• pp.17-26
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• 1998

Natural rubber was filled with 8 commercial carbon blacks covering range of rubber-grade products at different levels of filler loadings in order to investigate physical compound and vulcanizate properties. It was found that the curves of rubber property vs filler loading of both uncured compounds and vulcanizates can be superposed to one single master curve by introducing an effective volume fraction which is based on CDBP. The effective volume fraction, $V_{EFF}$ was utilized to explain the variation of the stiffness of all rubber compounds. The surface area-corrected effective volume fraction, V', was utilized to explain the formation of bound rubber, rebound and lambourn wear.

• Elastomers and Composites
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• 제36권1호
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• pp.30-36
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• 2001

이 연구의 목적은 카본블랙이 충전된 천연고무에서 비 등방성 발생에 영향을 주는 인자를 조사하기 위함이다. 고분자 사슬의 방향성은 인장특성에 영향을 준다. Pre-strained 방향의 parallel 시편은 등방성 혹은 perpendicular 시편에 비하여 낮은 인장영역에서 낮은 강도를 보이지만 높은 신장영역에서 높은 강도를 보인다. 고 인장 영역에서 parallel한 천연고무 시편은 비결정성인 SBR에 비하여 높은 강도를 보여주고 있다. 이것은 parallel 시편의 방향성에 영향을 받는 것으로, 시편의 방향성은 2차 인장시 결정화를 위한 핵으로 작용하여 결정화도를 증가시키는 것으로 보인다.

• Elastomers and Composites
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• 제51권3호
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• pp.218-225
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• 2016

In order to examine correlation between silane coupling agent and activator which affects the physical properties of silica filled natural rubber compound, such as heat buildup, rebound property, dynamic mechanical and morphological properties were measured. With incorporation of silane coupling agent, $tan{\delta}$ at $0^{\circ}C$ was increased and at $60^{\circ}C$ was decreased, which resulted in improving of wet grip and rolling resistance. When silane coupling agent which is corresponding to 8~10% of silica was used, most favorable heat build up and $tan{\delta}$ was obtained. And also when activator was used, dispersibility of silica was improved as a result of reduction of reaggregation of silica.

• Macromolecular Research
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• 제14권2호
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• pp.187-193
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• 2006

Organoclay, was applied as a filler, in place of carbon black and silica, to a natural rubber (NR)/butadiene rubber (BR) blend. A compounding method was used to disperse and separate the layered silicates. The effect of a coupling agent on the vulcanizates was evaluated using both the silica and organoclay filled compounds. After the compounding processes were completed, the XRD diffraction peaks disappeared, but then reappeared after vulcanization. The scorch times for the organoclay-filled compounds were very short compared to those for carbon black and silica-filled compounds. The organoclay-filled compounds showed high values of tensile strength, modulus, tear energy, and elongation at the break. When ranked by viscosity, the compounds appeared in the following order: silica > silica (Si-69) > organoclay > organoclay (Si-69) > carbon black. Fractional hysteresis, tensile set, and wear rates were very consistent with the viscosity of the vulcanizates. The Si 69 coupling agent increased reversion resistance, the maximum torque values in the ODR, modulus, and wear resistance, but decreased elongation at the break, fractional hysteresis, and tension set of the vulcanizates.

• Advances in materials Research
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• 제3권3호
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• pp.175-183
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• 2014

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide ($MePPh_3I$) by Wittig reaction ($0^{\circ}C$ for 2 hrs, $N_2$ atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer ($180^{\circ}C$ for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

• Macromolecular Research
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• 제9권1호
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• pp.37-44
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• 2001

A premixing effect for the properties of carbon black-filled rubber compounds was investigated using biblends of natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). Degree of mixing of the biblends was controlled by preblending time of 0.0, 2.5, and 5.0 min. Mooney viscosities of the compounds decreased by increasing the preblending time. Of three carbon black-filled compounds of NR/SBR, NR/BR, and SBR/BR compounds, only the SBR/BR blends showed a specific cure characteristics depending on the preblending time. For the bound rubber composition, the NR content was higher than SBR and BR. The difference in the rubber composition ratio of the bound rubber became smaller with increasing the preblending time. Physical properties of the vulcanizates such as hardness, modulus, tensile property, abrasion loss, and tans were also compared. Differences in properties of the compounds were discussed with miscibility of the dissimilar rubbers and degree of mixing.

• Elastomers and Composites
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• 제37권2호
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• pp.86-98
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• 2002

본 연구에서는 실리카/카본블랙 혼합사용과 카본블랙 단독 사용의 경우 상온 또는 고온에서의 인장강도(modulus) 및 인열저항성, 내cutting성, 내crack성을 비교 평가하였다. 실리카와 카본블랙의 함량비 및 단계배합 방법을 통해 NR 가황물을 제조하였으며, 충전제의 함량은 60phr로 고정하였고, semi-EV 가황시스템을 적용하여 실험을 실시하였다. 실리카의 분산은 25phr이하일 때 양호하였으며, 실리카/카본블랙의 함량비가 25/35인 경우 인열에너지, 내crack특성, 내cutting특성이 가장 우수하였다. 충전제로써 카본블랙 단독사용과 실리카/카본블랙(25/35) 혼합사용의 경우를 비교해 보면, 열화에 따른 modulus 및 인장강도, 인열에너지는 실리카/카본블랙(25/35)을 사용한 시편이 더 낮은 감소율을 나타내었다. Cutting특성에서는 카본블랙 단독 사용보다는 실리카/카본블랙(25/35) 혼합사용의 경우가 더 높은 cutting 저항성을 나타내었다. 내crack 특성 또한 실리카/카본블랙(25/35)을 혼합사용한 경우가 온도에 따른 더 높은 변형에너지 완화율(Gp)에도 불구하고 더 낮은 크랙성장속도를 나타내었다.

• Elastomers and Composites
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• 제59권1호
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• pp.8-16
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• 2024

As regulations on greenhouse gas emission have strengthened globally, the demand for improved fuel efficiency in automobiles continues to rise. In response, the tire industry is actively conducting research to improve fuel efficiency by enhancing tire performance. In this study, silica-filled epoxidized natural rubber (ENR)/butadiene rubber (BR) blend compounds were manufactured according to ENR types and silica contents, and their physical properties and vulcanizate structure were evaluated. ENR-50, which has a higher epoxide content than ENR-25, exhibited stronger filler-rubber interaction, resulting in superior abrasion resistance. In addition, because of its high glass transition temperature (T_g), the wet grip performance of ENR-50 improved, even though the rolling resistance increased. Increasing the amount of silica had little effect on the abrasion resistance due to the increase in filler-rubber interaction and decrease in toughness. In addition, ENR-50 exhibited better wet grip performance; however, the rolling resistance increased. The results indicated that truck bus radial (TBR) tire tread compounds can be designed by applying ENR-50 to improve wear resistance and wet grip performance. In addition, by applying ENR-25 and reducing the silica contents improve fuel efficiency.

• Elastomers and Composites
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• 제20권1호
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• pp.25-39
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• 1985

Elastomer-filler interaction in terms of characterization of filler effects was studied using natural rubber(NR) loaded with kaolin fillers modified with sodium polyphosphate and poly(maleic anhydride), respectively. Kaolins modified with sodium polyphosphate or poly(maleic anhydride) show adhering characteristics by Kraus plot. Reinforcement activity according to Cunneen-Russell method is given by those fillers, in which sodium polyphosphate-treated kaolin presents more favorable results than that treated with poly(maleic anhydride) with respect to adhesion constant, reinforcement extent, elastic constant, and crosslink density. When applied to Blanchard's linkage reinforcement theory, NR vulcanizates loaded with kaolin modified with sodium polyphosphate meet the requirements for both approximate linkage reinforcement(${\psi}'$) of 1.02 to 4.94 and accurate linkage reinforcement($\psi$) of 1.00 to 1.18, representing the values of effective wetting($C_{\psi}$) for 0.001 to 0.029 and intrinsic linkage reinforcement(${\psi}_0$) for 1.015 to 1.124, respectively, whille negligible linkage reinforcement is shown by NR vulcanizates loaded with kaolin treated with poly(maleic anhydride). Dynamic storage modulus(G') given by surface modified kaolins presents more favorable crosslink density rates of $2.260{\times}10^{-5}\;mole/cm^3-min$. for sodium polyphosphate treated kaolin and $1.305{\times}10^{-5}\;mole/cm^3-min$. for poly(maleic anhydride) treated kaolin, respectively, compared to untreated kaolin showing the rate of $1.033{\times}10^{-5}\;mole/cm^3-min$.