가황시스템 변화가 배합고무의 가황반응속도 및 물리적 특성에 미치는 영향

이석,박남국,Lee, Seag,Park, Nam Cook 한국공업화학회 1999 공업화학 Vol.10 No.3

가황고무의 가황반응에 대하여 가황시스템 및 온도, 보강성충전제 첨가량 변화에 의한 반응속도상수 및 활성화에너지, 가교밀도 및 탄성상수, 가황특성 ($t_5,\;t_{90}$), 고무보강성 및 내마모성을 고찰하였다. 반응속도상수는 보강성충전제 첨가량, 가황시스템 및 가황반응온도에 대한 의존성이 크게 나타났으며, 반응온도에 따라 지수적으로 증가하였다. 활성화에너지는 가황시스템중 촉진제에 대한 황 비율이 높은 가황시스템에서 가장 작게 나타났으며, 보강성충전제 첨가량이 적을수록 작게 나타났다. 카본블랙 첨가량 변화는 고무보강성 및 내마모성에 직접적으로 영향을 미치고 있으나, 가황시스템 변화는 각기 다른 영향이 나타났다. 카본블랙 첨가량이 증가하면 모듈러스가 증가하고, 내마모성이 향상되며, 스코치시간이 짧아졌으나, 가교밀도 및 탄생상수는 감소하였다. 높은 가교밀도 및 탄성상수는 카본블랙 첨가량에 관계없이 촉진제에 대한 황 비율 0.73 (${\fallingdotseq}1$)에서 나타났으며, 스코치시간 ($t_5$)은 촉진제에 대한 황 비율 변화에 거의 영향을 받지 않는 것으로 나타났다. 빠른 최적가황시간 ($t_{90}$) 역시 촉진재에 대한 황 비율이 1에 가까운 조건 (=0.73)에서 나타났다. 가황조건별 배합고무의 등가 가황곡선계수는 카본블랙 첨가량에 관계없이 CC 시스템에 대해서는 0.96, SEC 및 EC 시스템에 대해서는 0.74로 나타났다. 한편 가황고무의 마모된 부피는 부과된 하중이 증가함에 따라 지수적으로 증가하였다. In this study, the reaction rate constant, activation energy, total crosslinking density, elastic constant, cure properties ($t_5,\;t_{90}$), modulus, and abrasion resistance of rubber compounds were investigated as a function of cure temperatures, cure systems and reinforcing filler loadings. Reaction rate constants showed strong dependence on thc carbon black loading, cure temperature and cure system, and increased sharply with increasing the reaction temperatures. The lowest activation energy was obtained in the efficient cure (EC) system which corresponds to the high level of sulfur to accelerator ratio, and the activation energy was decreased with decreasing the carbon black loadings. The change of carbon black loadings directly affects the modulus and abrasion resistance, but the change of cure system showed various effects on the rubber compounds. Increased carbon black loadings showed the high modulus, improved abrasion resistance and short scorch time but decrease in crosslinking density and elastic constant. Higher crosslinking density and elastic constant were shown in the EC cure system regardless of carbon black loadings, but scorch timc ($t_5$) was not affected by the change of the ratio of sulfur to accelerator. Rapid optimum cure time ($t_{90}$) were showen in the EC cure system. Also, the equivalent cure curve coefficient of rubber compound was 0.96 for conventional cure (CC) system, and 0.94 for semi-efficient cure (SEC) and EC system regardless carbon black loadings. As regarding the abrasion resistance, wear volume showed the logarithmic increase for the loaded weight.

가황시스템 변화가 배합고무의 가황반응속도 및 물리적 특성에 미치는 영향

이석(Seag Lee),박남국(Nam Cook Park) 한국공업화학회 1999 공업화학 Vol.10 No.3

N/A N/A

가황시스템 변화가 가황고무의 점탄성적 특성에 미치는 효과

이석(Seag Lee),박남국(Nam Cook Park) 한국고무학회 1999 엘라스토머 및 콤포지트 Vol.34 No.1

N/A Rebound, storage and loss modulus, and tan δ were investigated on cured rubbers with various ratios of sulfur to accelerator and the volume fraction of carbon black in the cured rubbers. The rebound was increased as the sulfur to accelerator ratio and the volume fraction of carbon black decreased. The storage modulus decreased as the loading of carbon black and the strain increased regardless of the cure systems. The network structure formed by filler-filler interaction was destroyed above 6% strain regardless of the loading of carbon black, because constant storage modulus was shown at the higher strain than 3% for 40∼50 phr loading of carbon black and at the higher strain than 6% for 60 phr and above loading of carbon black. Little effect on loss modulus was found at the low loading of carbon black, but the peak of loss modulus was shown at 1% strain as the loading of carbon black was increased. Tan δ increased as the loading of carbon black and the strain were increased regardless of the cure system, and maximum tan δ was shown at 2% strain regardless of the loading of carbon black.

이중상 구조를 가진 보강성 충전제의 물리적 특성 연구

이석,박남국 ( Seag Lee,Nam Cook Park ) 한국공업화학회 1998 공업화학 Vol.9 No.4

가황조건별 배합고무의 가교밀도와 고무보강성에 관한 연구

이석(Seag Lee),박남국(Nam Cook Park) 한국고무학회 1998 엘라스토머 및 콤포지트 Vol.33 No.5

N/A The purpose of this study was to investigate the crosslinking density and reinforcement of rubber compounds with various carbon black loadings, cure systems and cure temperatures. Bound rubber content increased with volume fraction of carbon black in rubber compounds, but total crosslinking density decreased with increasing the bound rubber content. Rate constant of cure reaction was changed significantly by cure system and cure temperature, especially it showed strong dependence on the cure temperature. High activation energys of cure reaction were shown in the rubber compound with high loading of carbon black under EC system and in the rubber compound with low loading of carbon black under CC system. High total crosslinking density of vulcanized compounds appeared in the rubber compound with low loading of carbon black and CC system among cure systems. Typical change of total crosslinking density by EC system was not shown. The highest elastic constant by Mooney-Rivlin equation was shown in the rubber compound with low loading of carbon black and SEC system. Modulus increased as increasing the loading of carbon black in the rubber compounds and showed the order of SEC, CC, and EC system for cure system.

실리카가 도핑된 카본블랙을 함유한 고무조성물의 물성에 관한 연구

박남국,이석 한국고무학회 1998 엘라스토머 및 콤포지트 Vol.33 No.1

The purpose of this experiments were investigated on the physical properties of rubber compounds containing two types carbon black. Bound rubber and interaction coefficient for compounds with pure carbon black were higher than those for the compounds with dual phase carbon black. Slightly higher values in 300% modulus and tensile strength indicated that the ratio of rubber-filler bound to rubber-rubber bound of pure carbon black were higher than those of compounds with dual phase carbon black. It was founded that dynamic properties, that is rebound, heat build-up, 0 & 60℃ tan δ, and cut and chip loss of compounds with dual phase carbon black were better than those of compounds with pure carbon black, but abrasion property of dual phase carbon black was lower than those of pure carbon black because of low reinforcing ability.

고무조성물의 물리적 성질에 영향을 미치는 주요인자에 대한 통계학적 해석

박남국,이석 한국고무학회 1997 엘라스토머 및 콤포지트 Vol.32 No.1

This study have investigated the effect of various factors related to the physical properties of vulcanizated rubber compounds. rubber type, carbon black type and carbon black loading were selected as main factors and evaluation were tested by tables of orthogonal arrays with 3 factors and 3 levels. rubber types have affected cure time, tensile strength, and T_g as main factor and carbon black loading have affected viscosity, scorch time, maximum torque, hardness, 300% modulus, rebound, heat build-up, 0 & 60℃ tangent delta, PICO and CUT/CHIP loss as main factor but the effects of carbon black type have affected only bound rubber content.

고무조성물의 접착특성에 영향을 미치는 주요인자에 대한 통계학적 해석

오인석,박남국,이석 한국고무학회 1997 엘라스토머 및 콤포지트 Vol.32 No.2

The effect of type of elastomar, the type and loading of carbon black in rubber compounds on the adhesion properties with brass plated steel cord was investigated. The orthogonal arrays with 3 factors mentioned above and 3 levels as used. In the unaged adhesion samples, the elastomer type was a main factor on adhesion force and rubber coverage and the loading of carbon black was a subfactor. In the aged adhesion samples such as thermally or humidly, elastomer type was a main factor but the loading of carbon black was a main factor in the case of prolonged aging occasionally.

카본블랙 표면특성과 폴리머블랜드 물성에 관한 연구

오세철,고진환,박남국,이석 한국고무학회 1995 엘라스토머 및 콤포지트 Vol.30 No.5

After mixing different grades of carbon black in NR/BR blends and in NR/SBR blends, we found if the ratio of N2SA to I2NO which indicates the degree of surface active carbon black increased, the amount of bound rubber proportionally increased too. However, the amount of bound rubber per unit specific surface area decreased. Exceptionally NCB-1 black which is the same particle size as the other carbon black increased. This phenomenon can be seen in the NR/BR blends rather than in the NR/SBR blends. In vulcanizing properties, the surface active carbon blacks such as NCB-1, NCB-2 were a short scortch time than ordinary carbon blacks, althogh there were almost no effect to the optimum cure time. Finally, the surface active blacks were superiour to the ordinary blacks in connection with loss of abrasion and loss of cut & chip, especially in the NR/BR blends.

고무물성 향상을 위한 실리카 및 실란 커플링제의 최적배합에 관한 연구

오세철,고진환,박남국,이석 한국고무학회 1995 엘라스토머 및 콤포지트 Vol.30 No.2

The physical properties of rubber compounds containing silica and siliane coupling agent in order to replace the carbon black and prepare for environmental regulation showed improved dynamic properties(rebound, heat build-up, 60℃ tan δ), but the abrasion resistance did not improve compared with the compounds containing carbon black. Also, curing retardation because of coherent structure of silica improved by the addition of DEG, but the mixing step change of activators did not so much improve the static and dynamic properties of the compounds containing high synthetic rubber, the status of mixing and dispersion showed that the compounds containing carbon black was much better than the compounds containing silica by TEM investigation.