• Elastomers and Composites
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• v.54 no.2
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• pp.91-96
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• 2019

The purpose of this study was to examine the effect of different yarn twisting methods on physical properties. Plain single jersey structured fabrics were knitted from Kevlar yarn, and from Kevlar/HPPE, and from Kevlar/Basalt fiber, and from Kevlar/Glass fiber and Kevlar/Stainless steel fiber blended and core-spun yarns. and then, The fabrics were coated NBR Latex. The physical properties, including tear strength, modulus, degree of penetration, heat resistance, and cut resistance of the knitted fabrics were investigated and compared. Kevlar/HPPE blended yarn fabrics recorded the highest heat resistance (13 Sec.). and Kevlar/HPPE blended yarn fabrics had good cut resistance (Cut Level 4).

• Journal of Adhesion and Interface
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• v.9 no.2
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• pp.24-31
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• 2008

In this work, calcium hydroxide and magnesium carbonate as metal ionic crosslinking agents were used to introduce ionic crosslinking points to the ethylene vinylacetate (EVA) emulsions for the enhancement of water resistance and mechanical properties of emulsion films. The properties of EVA emulsion film were investigated in crosslinking density, thermal features, surface energy, and mechanical properties, such as tensile strength, elongation at break and tear strength. With the increasing content of metal ionic crosslinking agent, the crosslinking density of the EVA emulsion film increases, resulting into the improvement of water resistance. The surface energy and mechanical properties of the EVA emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.4% for calcium hydroxide and 0.5% for magnesium carbonate was added respectively, because the EVA emulsion containing carboxylic acid forms strong carboxylate-metal bond of ionically-crosslinked system. Therefore, it can be concluded that metal ionic crosslinking agents, such as magnesium carbonate and calcium hydroxide are considered to improve water resistance and mechanical properties of the EVA emulsion.

• Polymer(Korea)
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• v.28 no.2
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• pp.185-193
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• 2004

Elastomeric nanocomposites were prepared by employing zinc dimethacrylate into an acrylonitrile-butadiene rubber, and their network structures, mechanical properties, and fracture morphologies were investigated according to the adding methods and contents of zinc dimethacrylate. The total crosslink density increased with increasing the zinc dimethacrylate level, due to increased ionic bonds. Both the tensile strength and tear strength increased with increasing zinc dimethacrylate loadings, and then decreased after reaching a maximum value. It was found that the tear strength and crack resistance were greatly affected by the mixing method of zinc dimethacrylate. The in-situ nanocomposites, where zinc dimethacrylate particles were formed by the reaction of zinc oxide and methacrylic acid, showed much improved tear strength and crack resistance compared to those of the nanocomposites based on the direct mixing of zinc dimetacrylate powders. This was because of the finer zinc dimethacrylate particles and improved dispersion of the in-situ nanocomposites.

• Journal of Industrial Technology
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• v.36
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• pp.39-43
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• 2016

The purpose of this study is to determine and compare the mechanical and flow properties of polyvinylsiloxane impression pastes. Twelve polyvinylsiloxane impression materials were used. As mechanical properties, tensile strength and tear resistance were measured. Impression materials are subjected to tensile stresses when they are removed from the oral cavity and from stone models and tear resistance is the ability of the material to resist tearing under a tensile stress. Flow is dependent on the ability of the material to resist shear forces. Flow tests were performed to determine the handling characteristics and was measured using a shark fin testing device. An impression material must be able to penetrate the narrow subgingival sulcus and tight interproximal areas. Therefore, it must be able to resist the shear forces as it is pushed between tooth and gingival walls. It is necessary to understand the properties of interocclusal recording materials and is considered that the results obtained in this study will provide guideline information for the manufacturing of impression materials and for selecting appropriate impression materials.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.2
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• pp.14-22
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• 2007

In this paper, the acoustic emission(AE) behaviors were investigated with single-and 2-spot resistance spot welded SPCC specimens. Test specimens were welded horizontally and/or vertically according to the rolling direction of base netal in 2-spot welding. In the case of 2-spot welding, when tensile-shear test has below amplitudes: crack initiation $50{\sim}60dB;$ tear fracture $40{\sim}50dB$. And when cross tensile test has below amplitudes: early stage $75{\sim}85dB;$ yielding point $65{\sim}75dB;$ post yielding $40{\sim}60dB;$ plug fracture $70{\sim}80dB\;or\;90{\sim}100dB$. Also, from the b-value that is slope of AE amplitude, we knew that there are lots of low amplitudes if b-value is big(i.e., tensile-shear $specimen{\rightarrow}tear$ fracture or shear fracture), and there are lots of high amplitudes if b-value is small(i.e.. cross tensile $specimen{\rightarrow}plug$ fracture). As the results of fiacture mechanism analyses through AE amplitude distributions, change of the b-value represented fracture patterns of materials. Correspondingly, low amplitude signals appeared in crack initiation, and high amplitude signals appeared in base metal fracture. We confirmed that these amplitude distributions represented the change or degradation of materials.

• Elastomers and Composites
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• v.7 no.2
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• pp.175-182
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• 1972

As a series of the studies of EPDM-Polymer blonds, the experiments are concentrated to the investigation of the physical properties of the EPDM-CR blends. The results are shown as follows: 1. In blending, tensile strength decreased with increase in EPDM contents and decreasing value was good results than various EPDM blending. 2. As EPDM Addition ratio is increased physical properties such as elongation have also improved, on the other hand, hardness and abrasion resistance decreased. 3. Aging resistance is less influenced by blending. 4. Tear strength is less influenced by blending and character after aging exhibited the same result. 5. Ozone resistance was much improved after blending. It was effective more than the ratio of EPDM/CR is 25/75.

• Elastomers and Composites
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• v.7 no.2
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• pp.183-192
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• 1972

As a series of tile studies of EPDM-Polymer blends, tile experiment are concentrated to the investigation of the physical properties of tile EPDM-NR-SBR blends. The results are shown as follows: 1. In blending, tensile strength decreased with increase in EPDM contents, especially the ratio of EPDM/NR-SBR is 75/25. 2. Elongation and tear strength were much influenced by blending, especially the ratio of EPDM/NR-SBR is 50/50. 3. Ozone resistance is much improved after blending. It was effective more than tile ratio of EPDM/NR-SBR is 25/75. 4. Aging resistance is much improved after blending. It was effective more than the ratio of EPDM/NR-SBR is 50/50. 5. Hardness increased with increase in EPDM contents and on the other hand, abrasion resistance decreased.

• Rubber Technology
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• v.5 no.2
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• pp.94-103
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• 2004

The present work describes modification of dual phase filler by electron beam irradiation in presence of multifunctional acrylates like trimethylol propane triacrylate (TMPTA) or silane coupling agent like bis (3-triethoxysilylpropyltetrasulphide) and in-fluence of the modified fillers on the physical properties of styrene-butadiene rubber (SBR) vulcanizates. Modulus at 300 % elongation increases whereas the tensile strength decreases with increase in radiation dose for the dual phase filler loaded styrene-butadiene rubber vulcanizates (SBR). However, modulus and tensile strength significantly increase, which is more, pronounced at higher filler loadings for TMPTA modified dual phase filler loaded SBR. These changes in properties are explained by the equilibrium swelling data and Kraus plot interpreting the polymer-filler interaction. Electron beam modification of the filler results in a reduction of tan ${\delta}$ at $70^{\circ}C$, a parameter for rolling resistance and increase in tan ${\delta}$ at $0^{\circ}C$, a parameter for wet skid resistance of the SBR vulcanizates. Finally, the influence of modified fillers on the properties like abrasion resistance, tear strength and fatigue failure and the improvement in the properties have been explained in terms of polymer-filler interaction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.69-71
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• 2003

Mechanical Properties, such as tensile strength, elongation, and tear strength, decreased according to increasing the load of ATH, volume resistivity, AC break down strength, and tracking resistance for HVI SC contained ATH treated by vinyl Silane were better than those for HVI SC were contained ATH treated by other surface treatment agent, such as stearic acid and acryl silane.

• Journal of the Korean Wood Science and Technology
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• v.27 no.1
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• pp.88-104
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• 1999

This study was carried out to classify the Hanjis into three groups that were indigenous Hanji, traditional Hanji, and improved Hanji handmade by paper making method according to the physical properties of each paper sheet such as tensile, bursting and tearing strength, folding endurance and fiber orientation in each layer. The results obtained were summarized as follows: 1. The multi-layered Hanjis made by "Oebal" Hanji making method in different direction of fiber orientation have good properties in tearing resistance. 2. The multi-layered Hanji in different direction of fiber orientation has good properties in the tearing resistance, but the burst index and the breaking length results were lower than the single layered Hanjis. 3. The different fiber orientation and multi-layered method didn't increase, the three indexes(burst index, tear index, breaking length). Only, the different direction of fiber orientation decreased the difference of width and length strength (tensile, tear) of the Hanji. 4. "Dochim"(Korean finishing touch process for indigenous Hanji by fulling round sticks) greatly increase folding endurance(double folds, not $log_{10}$) and good effect to tensile strength and burst strength. 5. The today's Oebal Hanji were the maximum of 2 layers and the indigenous Oebal Hanji were 16 layers the maximum. In addition, average of the indigenous Oebal Hanji was 4 layers(all 4-layer Hanji were the different fiber orientation of each layer). 6, The indigenous Hanji(multi-layered, and different fiber orientation) was good condition with "Dochim". Dochim increased tensile strength and burst strength of the indigenous Hanji. So the three-strength indexes were similar level("--"). 7. When the number of layer which were same fiber orientation increase, the increased Hanji became similar strength pattern("V", breaking length and burst index was higher than tear index) with "Ssangbal" Hanji. 8. The single layered papers that made by "Oebal" Hanji making method were similar strength pattern with Ssangbal Hanji. 9. There was no way to find the width and length direction of multi-layered Hanji by comparison between the difference of tensile strength and the difference of tearing resistance. 10. The compared pattern of tensile strength and tearing resistance of indigenous Oebal Hanji was different from today's Oebal Hanji. Especially, the tearing resistance of all indigenous Oebal Hanji(16 samples) was stronger on width of tearing resistance. And in the half of indigenous Oebal Hanji samples, the width of tensile strength and tearing resistance was stronger than length strength (Indigenous Oebal: '$\ulcorner\lrcorner$' 50%, '$\bigcup$' 50% $\leftrightarrow$ Today's Oebal: '$\ulcorner\lrcorner$' 12%, '$\bigcup$'6%, '$\llcorner\urcorner$'17%, '$\bigcap$'65%). In 65% today's Oebal, the length direction of tensile strength and tearing resistance was stronger than the width direction.