• Elastomers and Composites
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• v.22 no.1
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• pp.11-19
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• 1987

A coil pyrolyzer and processor-controlled gas chromatograph were used for analysis of rubber for compounding ratio of the single and blend rubber vlucanizates. Variables such as sample size, pyrolysis temperature, time allowed for pyrolysis, the column packing material, its length and programmable temperature for gas chromatography were examined to obtain optimum condition for application to NR, BR and SBR blends. By application fixed conditions, three kinds of standard curves were finally obtained from thirty samples of blend vulcanizates which were prepared in the pilot plant, NIRI. It is possible to determine rubber composition and their ratio in NR, BR and SBR products by pyrolysis.

• Elastomers and Composites
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• v.47 no.3
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• pp.246-253
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• 2012

This study was carried out to prepare a type of warm mix asphalt. Through urethane foam and emulsion asphalt preparation techniques a protocol of asphalt foam was made. Then three kinds of flame retardant agents were added in there to alleviate the inherent susceptability of asphalt and foam material to flame and thus flame retardant asphalt foam was made. The internal structure of form asphalt was composed of open cell. The higher the NCO% brought the larger the cell and the stronger also. Asphalt increased the strength of the foam. Among the flame retardant agents employed tritorylphosphate was the most effective.

• Elastomers and Composites
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• v.33 no.1
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• pp.37-43
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• 1998

The permeation of gas through polymer membrane at temperatures above its glass transition, generally occurs by a solution-diffusion mechanism. This mechanism is performed by the affinity difference between polymeric materials and gas molecules, and various technologies, such as copolymerization, impregnation and so on, have been researched to improve the affinity of polymeric material for the gases. In this study, permeability and selectivity for some gases were obtained from steady-state rates of gas permeation through silicone rubber membrane which is prepared by supercritical fluid extraction method. The permeability was measured by the volumetric method proposed by Barrer. Permeability was increased generally with temperature and permeation pressure. Silicone rubber membrane shows a higher permeability to $CO_2$ than to $O_2$, $N_2$. This results probably reflect the relatively high solubility of CO_2 in silicone rubber membrane, which is due to the affinity of $CO_2$ molecules. Since separation powers of $CO_2/N_2$, $CO_2/O_2$ were more than 200, and 100, respectively, it is able to separate $CO_2$ from the air, and the optimum temperature and pres-sure was 328.15 K, 60 cmHg respectively. In future, it is possible that the silicone rubber membrane can be used for separation or concentration of $CO_2$ through experiment for mixed gas separation.

• Composites Research
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• v.28 no.6
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• pp.402-407
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• 2015

It is well known that the polymer matrix composite materials have good specific strength, making them appropriate for use in transport vehicle. Since the property of composite materials can be obtained only after manufacturing parts, the property depends on greatly on the fabrication process, which is different from metallic system. Therefore, in order to use composite materials for aircraft, the certifying agency requires a robust database with extensive tests and proof of the process unlike metals. Recently developed material qualification methodology by NCAMP (National Center for Advanced Materials Performance) has been accepted by FAA and EASA and can be applied to type certificate reducing time and cost of developing a composite materials database for aircraft application. This paper summarizes a study to establish the composite materials database to apply the NCAMP methodology to composite materials characterization for composite aircraft and to provide the effective materials database through Aerospace Composite Materials Data Center to be approved by Korea Civil Aviation Certification Agency.

• Advanced Composite Materials
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• v.16 no.2
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• pp.181-194
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• 2007

This paper presents the mechanical properties of a composite consisting of acrylonitrile-butadiene-styrene (ABS) resin mixed with carbon fiber reinforced plastics (CFRP) pieces (CFRP/ABS). CFRP pieces made by crushing CFRP wastes were utilized in this material. Nine kinds of CFRP/ABS compounds with different weight fraction and size of CFRP pieces were prepared. Firstly, tensile and flexural tests were performed for the specimens with various CFRP content. Next, fracture surfaces of the specimens were microscopically observed to investigate fracture behavior and fiber/resin interface. Finally, the tensile modulus and strength were discussed based on the macromechanical model. It is found that the elastic modulus increases linearly with increasing CFRP content while the strength changes nonlinearly. Microscopic observation revealed that most carbon fibers are separated individually and dispersed homogeneously in ABS resin. Epoxy resin particles originally from CFRP are dispersed in ABS resin and seem to be in good contact with surrounding resin. The modulus and strength can be expressed using a macromechanical model taking account of fiber orientation, length and interfacial bonding in short fiber composites.

• Particle and aerosol research
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• v.13 no.4
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• pp.183-189
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• 2017

Potassium hexatitanate ($K_2Ti_6O_{13}$) with high thermal insulating capacity, good mechanical properties, and excellent chemical stability are promising functional materials in the field of reinforcing material, heat insulating paints and automotive brake linings. In this study, we successfully synthesized rod-shaped potassium hexatitanate ($K_2Ti_6O_{13}$) by aerosol spray drying and post heat treatment as an eco-friendly process. The $KHCO_3-TiO_2$ porous particles were firstly synthesized from a colloidal mixture of $K_2CO_3$ and $TiO_2$ via aerosol spray drying. Size of $KHCO_3-TiO_2$ porous particles was ranged from $1{\mu}m$ to $5{\mu}m$. The porous particles were then heated to fabricate rod-type $K_2Ti_6O_{13}$. The length and width of rod-type composites were affected by temperature and heating time. The length and width of $K_2Ti_6O_{13}$ were increased by 830 nm and 500 nm, respectively, as the reaction temperature and time increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.164-165
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• 2015

Recently, the reason of using foamed concrete is for core of panel, filler of construction material to give lightness. However, cement causes environmental problem. The cement generates CO₂ but we normally use cement during manufacturing foamed concrete. Accordingly, this study focuses on dynamic properties of matrix according to the addition ratio of paper ash to make lightweight matrix with blast furnace slag and paper ash which are industrial by-product. The experiment progessed in order to select th optimum mixing ratio of the blast furnace slag and paper ash. There are totally 7 levels such as B100:P0, B95:P5, B90:P10, B85:P15, B80:P20, B75:P25, B70:P30 in this study. As a result of the test, B95:P5 matrix has the best density and compressive strength.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.67-70
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• 2004

An investigation was performed to study the impact damage of the laminated composite plates caused by a low- velocity foreign object with multi-scale modeling based on the concepts of Direct Numerical Simulation (DNS)[4]. In the micro-scale part, we discretize the composite plates through separate modeling of fiber and matrix for the local microscopic analysis. A micro-scalemodel was developed for predicting the initiation of the damage and the extent of the final damage as a function of material properties, laminate configuration and the impactor's mass, etc. Anda macro-scale model was developed for description of global dynamic behavior. The connection betweenmicroscopic and macroscopic is implemented by the tied interface constraints of LS-DYNA contact card. A transient dynamic finite element analysis was adopted for calculating the contact force history and the stresses and strains inside the composites during impact resulting from a point-nose impactor. The low-velocity impact events such as contact force, deformation, etc. are simulated in the macroscopic sense and the impact damages, fiber-breakage, matrix cracking and delamination etc. are examined in the microscopic sense.

• Composites Research
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• v.12 no.2
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• pp.26-35
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• 1999

This paper presents the vibration damping characteristic of a single lap joint beam with partial dampers analyzed using the model strain energy method and the harmonic response analysis which were based on a finite element model. The two finite element analysis methods exhibited very similar results of the resonant frequency and system loss factor which were comparable to those by the theoretical analysis. Effects of the location of partial dampers and elastic moduli and thickness of their layers on the system loss factor were studied. The damping effects due to changes of modules and loss factor of the viscoelastic layer in lap joint and partial dampers were also studied. Consequently, the geometrical and material conditions at maximizing the system loss factor were suggested.

• Composites Research
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• v.12 no.2
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• pp.46-52
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• 1999

In this paper result of an analytical investigation pertaining to the elastic buckling behavior of orthotropic plate under combined in-plane shear and bending forces is presented. The existing analytical solution developed for the isotropic plates is extended so that the orthotropic material properties can be taken into account in the buckling analysis of web plate. For the solution of the problems Rayleigh-Ritz method is employed. Graphical form of results for finding the elastic buckling strength of orthotropic plate under combined in-plane shear and bending forces is presented. Brief discussion on the design criteria for the shear and bending interaction is also presented.