• Elastomers and Composites
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• v.46 no.3
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• pp.204-210
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• 2011

In this study, Jute fibers reinforced polypropylene (JFRP) composites were manufactured by injection molding technique. In order to improve the affinity and adhesion between fibers and thermoplastic matrices during manufacturing, Maleic anhydride (MA) as a coupling agent have been employed. Untreated and treated surfaces of jute fibers were characterized using SEM and Fourier transform infrared (FTIR). Physical properties like water absorption rate were studied. Tensile and flexural tests were carried out to evaluate the composite mechanical properties. Tensile test and bending test indicated that JFRP composites show higher strength and modulus than pure PP. In addition, strength and modulus were found to be influenced by the variation of MAPP content (1%, 2%, and 3%). Tensile fracture surfaces were examined using scanning electron microscope. It ensures better interfacial adhesion between fibers and matrix by increasing the percentage of MAPP.

• Elastomers and Composites
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• v.44 no.3
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• pp.290-298
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• 2009

In this paper, the Fe-activated carbon fiber (ACF)/$TiO_2$ composite catalysts were prepared by a sol-gel method. The synthesized photocatalysts were used for the photo degradation of Methylene blue solution under UV light. From Brunauer-Emmett-Teller measurements (BET) data, it was shown the blocking of the micropores on the surface of ACF by treatment of Fe and Ti compound. As shown in SEM images, the ferric compounds and titanium dioxides were fixed onto the ACF surfaces. The result of X-ray powder diffraction showed that the crystal phase contained a mixing anatase and rutile structure and the 'FeO+$TiO_2$' from the composites. The EDX spectra for the elemental analysis showed the presence of C, O, and Ti with Fe peaks. Degradation activity of MB could be attributed to +OH radicals derived from electron/hole pair's reactions due to photolysis of $TiO_2$ and photo-Fenton effect of Fe.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.347-356
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• 2023

Liquid crystal elastomer (LCE) fibers have been widely applied in various fields, such as soft robots and biomimetic actuators, in a one-dimensional form. LCEs possess the characteristics of both fluidity and solid order, as well as the elasticity of rubber, and exhibit stimulus-response based on these properties. In particular, by programming the responsiveness to various stimuli such as heat, light, electric fields, and magnetic fields in terms of shape-changing, various movements such as lifting, twisting, and rotating can be realized with high degrees of freedom. Therefore, LCE fibers have the potential for application in various fields such as artificial muscles, soft robots, wearable technologies, and sensing technologies. The research on liquid crystal elastomer fibers is evaluated to have high applicability in various fields in the Fourth Industrial Revolution as a smart material that can include various functionalities beyond simple fibers. In this review, we introduce the structure and basic characteristics of liquid crystal elastomer fibers, the latest research trends on orientation-based fabrication methods, and various applications such as artificial muscles, smart fabrics, and soft robots.

• Composites Research
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• v.20 no.4
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• pp.1-8
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• 2007

In this study, carbon fiber reinforced polymeric (CFRP) composites with different resin composition were manufactured and resin formulation in composite materials were presented through tensile tests for cryogenic use. Thermo-mechanical cyclic loading (up to 6 cycles) was applied to CFRP unidirectional laminate specimens from room temperature to $-150^{\circ}C$. Tensile tests were then performed at $-150^{\circ}C$ using an environmental test chamber. In addition, matrix-dominant properties such as the transverse and in-plane shear characteristics of each composite model were measured at $-150^{\circ}C$ to examine the effects of resin formulation on their interfacial properties. The tensile tests showed that the composite models with large amounts of bisphenol-A epoxy and CTBN modified rubber in their resin composition had good mechanical performance at cryogenic temperature (CT).

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.37-42
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• 2003

The mechanical components with high-pressure hoses are generally produced by the swaging process. The hoses are composed of the rubber materials and the reinforced braids to support tensile forces. In case they are subjected to high mechanical and thermal loads under severe operating conditions, the oil in hoses can leak at the parts of small clamping forces. In this paper, the deformation characteristics of a fiber-reinforced hose are analyzed with respect to the jaw strokes using the finite element method. The manufacturing process is modeled with a contact problem in consideration of a real situation, and the material properties based on the experimental results are used in the analysis. Examinations of the relationship between the swaging strokes and the deformation behaviors of the hose were made on the basis of the stress and strain values of the hose components. The relations between clamping forces and separating forces are also proposed, in order to estimate clamping forces corresponding to separating forces for the given model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.2
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• pp.247-254
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• 2008

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material, which has the most to do with the floor impact sound reduction. The resilient materials available in Korea include EPS(styrofoam), recycled urethane types, EVA(ethylene vinylacetate) foam rubber, foam PE(polyethylene). glass fiber & rock wool, recycled tire, foam polypropylene. compressed polyester, and other synthetic materials. In this study, we tested dynamic stiffness of resilient material and floor impact sound reduction characteristic to a lot of kinds of resilient materials. It was found that dynamic stiffness of multi-layered damping material could be estimated if know value of each layer that compose whole structure. And the test showed that the amount of the heavy-weight impact sound reduction appeared by being influenced from this dynamic stiffness of resilient material. The dynamic stiffness looked like between other resilient materials, a similar to the amount of the heavy-weight impact sound reduction was shown.

• Polymer(Korea)
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• v.24 no.5
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• pp.690-700
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• 2000

In this study, an elastomer-assistered compression molding process was investigated by experiments as well as modeling for the long-fiber reinforced thermoset composites. The consolidation pressure generated by fixed-volume and variable-volume conditions was thermodynamically derived for both elastomer and curing prepregs, and was compared with the pressure measured during curing of epoxy matrix. Exhibiting non-linear viscoelastic characteristics in the compressive stress-strain tests, the measured stress was well compared with a modifed KWW (Kohlrausch-Williame-Watts) equation, which is based on the Maxwell viscoelastic model. Using the developed model equations, the consolidation pressure generated by the elastomer was successfully predicted for the compression molding process of thermoset composite materials in tile closed mold system.

• Journal of the Korean Geosynthetics Society
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• v.4 no.3
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• pp.3-10
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• 2005

This paper aims at investigating the characteristics of discharge capacity according to lateral pressure, hydraulic gradient and deformation of drain materials. A series of experiments were conducted to achieve this objective. In experiments, fiver drain boards as well as harmonica and castle types of drain boards were installed in a rubber membrane, and clay in sully was filled around them. The test results showed that the harmonica type of drain boards have the greatest discharge capacity comparing to castle and fiber drain boards. The results also indicated that the hydraulic gradient has more effect on reduction of discharge capacity than the lateral pressure.

• Elastomers and Composites
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• v.54 no.4
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• pp.308-312
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• 2019

Polyphenylene sulfide (PPS) is a well-known super engineering plastic with a high melting temperature (above 290℃). It is generally insoluble under regular conditions. Therefore, it can be used for replacing metallic materials. Many researchers are looking at the possibility of replacing aluminum in the engine compartment of an automobile. However, studies on PPS are not common as compared to conventional engineering plastics because only a few companies produce super engineering plastics. In this research, the material properties of PPS composites containing two different kinds of glass fibers and produced under different processing temperatures were investigated. The tensile strength of the PPS composites increased as the processing temperature increased. Although glass fibers with similar aspect ratios were compounded under the same processing condition, one of them yielded a higher mechanical strength.

• Elastomers and Composites
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• v.55 no.2
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• pp.120-127
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• 2020

In this study, molding shrinkage of PPS resin was investigated. Two types of PPS resins with differing glass fiber and calcium carbonate content were used for this purpose. To observe mold shrinkage, molding conditions based on injection temperature, injection speed, and the position of the cushion were selected. Circular and rectangular specimens were used for the study model. Injection molding simulation was performed to predict the filling pattern and mold shrinkage, and the simulation results were compared with the experimental conclusions. It was observed that the mold shrinkage showed the highest shrinkage (distributed from 0.05% to 0.32%) dependence on the injection temperature, and the lowest shrinkage (distributed from 0.05% to 0.31%) dependence on the injection speed. The role of the position of the cushion in mold shrinkage was difficult to observe. The results of the simulation mostly agreed with the experimental results; however, for some molding conditions, the mold shrinkage in the simulation was overestimated as compared to that in the experiment.