• Elastomers and Composites
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• v.34 no.1
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• pp.11-19
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• 1999

Rebound, storage and loss modulus, and tan ${\delta}$ 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 $40{\sim}50phr$ 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 ${\delta}$ increased as the loading of carbon black and the strain were increased regardless of the cure system, and maximum tan ${\delta}$ was shown at 2% strain regardless of the loading of carbon black.

• Elastomers and Composites
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• v.39 no.2
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• pp.95-104
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• 2004

New compounds were made using various NR/BR blend ratio and oil content to improve mechanical properties of rubber isolator at low temperature. Mechanical properties were investigated as a function of NR/BR blend ratio and oil content. Hardness and tensile modulus generally increased, but tensile strength and elongation at break decreased with increasing BR content. Hardness, tensile modulus and tensile strength decreased, but elongation at break were nearly the same with increasing oil content. The glass transition temperature of NR and BR were found to be $-50^{\circ}C$ and $-90^{\circ}C$ respectively based on the abrupt drops in storage elastic modulus and peak of loss factor. Two distinct transition temperature were observed in NR/BR blend compounds and each transition point was not affected by blend level indicating incompatible nature of NR/BR blend.

• Elastomers and Composites
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• v.46 no.4
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• pp.311-317
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• 2011

The neodymium magnet inserted mold was proposed to orient magneto-responsible particles efficiently. The anisotropic magneto-rheological elastomer(MRE) was prepared using the new mold and the optimum amounts of the particles was 30 vol.%. As the orientation of particles was increased, the tensile strength of MRE was decreased, while the hardness of MRE was increased. It was found that the MRE containing 30 vol.% of magneto-responsible particles showed the maximum magneto-rheological effect. The ratio of shear modulus shift was 59% at the input current of 3 A. The transmissibility of MRE was decreased with increasing the input current and loading amounts of magneto-responsible particles. Therefore, the damping property of MRE could be improved by preparing the anisotropic MRE.

• Elastomers and Composites
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• v.36 no.2
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• pp.111-120
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• 2001

Mechanical properties and their adhesion behavior with zinc- and brass-plated steel cords of natural rubber/acrylonitrile-butadiene blend compounds were investigated as a function of blend ratio. The Mooney viscosity and stress relaxation time were found to be lowered with increasing NBR content. Tensile modulus generally increased with increasing NBR content. Tensile stress at break stayed constant up to about 40 phr and showed minimum at $50{\sim}60 phr$, and thereafter increased with increasing NBR content. Strain at break decreased linearly below 50 phr, and above the level it showed nearly constant value. Based on the abrupt drops in elastic modulus and tan ${\delta}$ peak, the glass transition temperature of NR and NBR were found to be -55 and $-10^{\circ}C$, respectively. In the case of NR/NBR blend compounds, two distinct transition points were observed and each transition position was not affected by NBR level indicating an incompatible nature of NR/NBR blend system. The pullout force and rubber coverage decreased to the level of about 40% to that of pure m compound, when the 50 phr of NR was replaced by NBR. However, the pure NBR compound showed the comparable adhesion performance with NR(${\sim}90%$). The sulfur concentration was found to become lower with the increased NBR content at the adhesion interface based on the Auger spectrometer results, representing a lack of adhesion layer formation, and this was explained for a possible cause of low adhesion performance with adding NBR.

• Elastomers and Composites
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• v.12 no.2
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• pp.157-164
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• 1977

(1) 탄성체(彈性體) MBMA를 가황제(加黃劑)로 사용한 가황체(加黃體)는 MOCA를 가황제(加黃劑)로 한 것 보다 Pot life가 긴 것이 특징(特徵)이다. 물리적(物理的) 특성(特性)에 있어서는 2가지 공(共)히 비승하였으나, 내열성(耐熱性)은 MOCA의 경우가 더 우수(優秀)하였다. 인장강도(引張强度), 신장률(伸張率), 반발탄성(反潑彈性)에 있어서는 MBMA를 사용(使用)한 가황(加黃體)와 MOCA를 사용(使用)한 가황체(加黃體)가 동일(同一)하였으나 압축(壓縮)줄음율은 전자(前者)가 높았다. 인열강도(引裂强度)에 있어서는 10부(部)의 MBMA를 가(加)했을 때 후자(後者)와 동일(同一)하였다. 또 MBIA 가황제(加黃劑)를 사용하였을 경우 인장강도(引張强度), 신장률(伸張率) 그리고 반발탄성등(反潑彈性等)이 MBMA 또는 MOCA의 경우와 거의 동일(同一)하였으나 고무가 부드러운 것이 특징이었다. 다만 100% 모듈러스의 경우 전자(前者)가 후자(後者)들보다 낮은 값이었다. NCO와 OH의 비(比)가 2 : 1인 Prepolymer를 사용한 MBIA가황체(加黃體)(MBIA를 가황제(加黃劑)로 한 가황체(加黃體))는 MBMA 가황체(加黃體) 또는 MOCA 가황체(加黃體)에 비(比)해 인열강도(引裂强度)는 낮았다. 그러므로 인열강도(引裂强度)를 향상(向上)시키기 위하여 NCO와 OH의 비(比)를 2 : 1보다 높은 비율(比率)로 취(取)하면 된다. 내열성(耐熱性)에 있어서 MBIA가황체(加黃體)가 MOCA가황체(加黃體)보다 우수(優秀)하였 고 또 배합작업(配合作業)에 있어서도 MOCA나 MBMA 가황체(加黃體)보다 작업성(作業性)이 용역(容易)하였는 바 이같은 이유(理由)는 전자(前者)의 녹는 점(點)$(70^{\circ}C)$이 후자(後者)들보다 낮기 때문이다. MBIA의 기타(其他) 특성(特性)으로서는 Pot life가 MOCA가황체(加黃體)보다 2.5배(倍) 길었다. 끝으로 MBEHA와 MBCHA가황체(加黃體)의 특징(特徵)은 가황속도(加黃速度)가 MBIA가황체(加黃體)보다 느림과 동시(同時)에 고무자체(自體)가 부드러웠을 뿐만 아니라 물리적(物理的) 특성(特性)도 좋지 않았다. (2) 미세구조용(微細構造用) 포옴라버 미세구조용((微細構造用) 포옴라버를 제조(製造)할 경우 이때까지 사용(使用)해온 MOCA가황제(加黃劑) 대신(代身) MBMA를 가황제(加黃劑)로 대체사용(代替使用)이 가능(可能)한 바, 이를 사용(使用)하였을 때의 물리적(物理的) 특성(特性)은 MOCA를 사용(使用)하였을 때 보다 인열강도(引裂强度), 신장률(伸張率) 그리고 열안정성등(熱安定性等)은 월등(越等)히 우수(優秀)하였다.

• Polymer(Korea)
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• v.37 no.1
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• pp.34-40
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• 2013

Commercially available polyamide thermoplastic elastomer (PA-TPE) was blended with hybrid filler which was prepared by means of the reaction between polyhedral oligomeric silsesquioxane (POSS) containing amine group and toluene diisocyanate (TDI)-caprolactam (CL) to explore the effect of blending the hybrid filler with the TPE. The chemical structure of the filler was identified by using FTIR and $^1H$ NMR. The composites, PA-TPE/POSS-(TDI+CL), which were the blends of TDI+CL modified POSS filler and PA-TPE up to 7 wt%, showed better elastic recovery delivered from lower tension setting compared to the PA-TPE and the PA-TPE/octaphenyl POSS blend. In addition the tensile strength and the initial modulus increased with increasing the hybrid filled content. Consequently it was assumed that the POSS-(TDI+CL) filler was a suitable material for enhancing strength and modulus without loss of elastic properties for the original PA-TPE.

• Elastomers and Composites
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• v.41 no.1
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• pp.49-56
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• 2006

The waste tire powder is modified with allylamine in the presence of ultraviolet radiation and the influence of surface modification on the thermal and rheological properties of polypropylene/waste tire powder composites was investigated. X-ray diffraction studies of PP/waste tire powder composite without compatibilizer, such as maleic anhydride-g-polypropylene (MA-PP), shows the increase in peak intensity of ${\beta}$ crystalline peaks, whereas it completely disappears in the presence of the MA-PP. Differential scanning calorimetry results further supported the above fact. The melt viscosities and storage modulus of the composites with modified waste tire powder show higher value than that of composites with unmodified powder and it is attributed to the interaction between amine group on modified powder surface and maleic anhydride of MA-PP.

• The Journal of the Convergence on Culture Technology
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• v.10 no.6
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• pp.635-640
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• 2024

The instrumented indentation test is a valuable analytical technique for analyzing the local properties of nanocomposite materials or the surface properties of thin coatings, such as films, which cannot be measured by traditional mechanical property measurement methods like tensile testing or Vickers hardness testing. This technique involves applying and removing a load on the surface of the target material using an indenter with a specific geometric shape. By continuously measuring the load and indentation depth during this process, an indentation-load curve is obtained and analyzed to determine the mechanical properties of the material. This study aims to derive the optimal measurement conditions for assessing the mechanical properties of polymer films coated on rigid substrates, such as displays, using a nanoindenter, which is the most representative instrument for the instrumented indentation test. Through the interpretation of the measurement results, the study seeks to analyze the mechanical properties of the polymer films coated on rigid substrates.

• Elastomers and Composites
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• v.46 no.1
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• pp.45-53
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• 2011

The effect of the silane coupling agent, bis(triethoxysilypropyl)tetrasulfide (TESPT), on mechanical properties of a silica-filled NBR compound for oilseal was investigated. Curing behavior and crosslinking density of the compounds were measured using ODR (oscillating disk rheometer) and swelling ratio in toluene. UTM (universal testing machine) and shore A hardness tester were used in order to study the characteristics of mechanical properties of original vulcanizates and aged ones with heated air and ASTM No. 3. oil. Recovery of elasticity which influences the performance and service life of oilseal was investigated by giving bending deformation to vulcanizates in aging condition. After bending aging test, recovery distance was measured and calculated angle of recovery from it. TR (temperature retraction) test was performed on these vulcanizates to determine the low temperature recovery behavior. Wear resistance was measured by Taber type abrasion tester. In addition, SEM was used to characterize the morphology of the worn surface of vulcanizates. The result showed that addition of TESPT into silica-filled compound improves not only compound flow-ability, interaction between NBR and silica and crosslinking density, but also hardness, 100% modulus, recovery of elasticity, wear resistance, heat resistance and ASTM No.3 oil resistance of vulcanizates.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.356-362
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• 1991

The physico-mechanical properties of NR/BR blend were measured, and the results were interpreted in terms of the crosslink density with cure system. The cure rate, maximum torque and crosslink density increase with the content and ratio of curative for cure system. Hardness, 300 % tensile modulus, rebound and wear resistance increase with crosslink density of the vulcanizate but heat build-up and tan $\delta$ at $60^{\circ}C$ decrease. It is expected that semi-EV(efficient vulcanization) cure system is appropriate for application in tire tread of truck/bus in which load bearing property is impotant.