• Composites Research
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• v.33 no.1
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• pp.7-12
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• 2020

Over the past decade, liquid crystalline epoxy (LCER) has attracted much attention as a promising matrix for the development of efficient heat dissipation materials. This study presents a comprehensive study including synthesis, preparation and chacterization of polymer/inorganic composites using typical 4,4-diglycidyloxybiphenyl (DP) epoxy among LECR. To confirm the thermal conductivity of composite materials, we have prepared composite samples composed of epoxy resin and single-wall carbon nanotube (SWCNT) as a filler. In particular, DP composites exhibit higher thermal conductivity than commercial epoxy composites that use the same type of filler due to the highly ordered microstructure of the LCER. In addition, the thermal conductivity of the DP composite can be controlled by controlling the amount of filler. In particular, the DP composite containing a SWCNT content of 50 wt% has the highest thermal conductivity of 2.008 W/mK.

• Polymer(Korea)
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• v.26 no.2
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• pp.260-269
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• 2002

The fire resistance of particulate polypropylene composite systems were investigated by using various reinforced particles such as zeolite, talc, $CaCO_3$ particles. In this study, The effect of particle size on the thermal properties of composite and the effect of reinforced particles on the fire resistance were studied. The inorganic reinforced particles used in this study were recycled zeolite(average particle diameter=85.34 $mu extrm{m}$), $CaCO_3$ (33.93 $mu extrm{m}$), and talc (18.51 $mu extrm{m}$). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863) and cone calorimetry (ASTM E1354, ISO 5660). Thermal stability of composite systems was thoroughly examined by measuring TGA. The flame retardants (DBDPO) and reinforced particles reduce the maximum heat release rate (M-HRR) in the order of Talc > $CaCO_3$ > recycled Zeolite. Comparing the cone calorimetry experimental results of the particle reinforced polymer composite system exhibited twice higher efficiency than DBDPO in polypropylene systems, and the LOI also showed similar trends to the cone calorimetry experiments. The optical and scanning electron microscopy techniques were used to investigate the composites ash layer and the core fracture surfaces in the burning process. The reinforcing inorganic particles seemed to accumulate at the surface of ash layer, and subsequently intercept the oxygen transport and heat transfer into the core area.

• Journal of the Korean Ceramic Society
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• v.51 no.1
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• pp.7-10
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• 2014

Abalone shell is composed of 95 wt% $CaCO_3$ platelets and 5 wt% of a protein-rich organic matrix which acts as an adhesive layer, connecting aragonite tablets, thus maintaining the structural integrity of the composite. By mimicking abalone shell, we prepared a silicate plate/polymer nanocomposite by infiltrating PMMA between silicate layers and warm-pressing them at $200^{\circ}C$ for 1 h under 15 tons to make organic-inorganic composite materials. To examine the organic-inorganic composite materials after the warm-pressing procedure, the composite sample was analyzed with FE-SEM and TG. The bending strengths and densities of the composites prepared by a silicate plate and PMMA after the warm-pressing process were ~140 MPa and 1.5, respectively.

• 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.

• Membrane Journal
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• v.29 no.1
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• pp.30-36
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• 2019

In this study, we reported a solid-state supercapacitor consisting of titanium nitride (TiN) nanofiber and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT-PSS) conducting polymer electrode and poly(vinyl alcohol) (PVA)-based polymer electrolyte membrane. The TiN nanofiber was selected as electrode materials due to high electron conductivity and 2-dimensional structure which is beneficial for scaffold effect. PEDOT-PSS is suitable for organic/inorganic composites due to good redox reaction with hydrogen ions in electrolyte and good dispersion in solution. By synergetic effect of TiN nanofiber and PEDOT-PSS, the PEDOT-PSS/TiN electrode showed higher surface area than the flat Ti foil substrate. The PVA-based polymer electrolyte membrane could prevent leakage and explosion problem of conventional liquid electrolyte and possess high specific capacitance due to the fast ion diffusion of small $H^+$ ions. The specific capacitance of PEDOT-PSS/TiN supercapacitor reached 75 F/g, which was much higher than that of conventional carbon-based supercapacitors.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.97-104
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• 2004

Double-layered polysulfone composite films, containing cerium activated yttrium silicate (CAYS) as a flour, were prepared from double casting of two polymeric solutions, and their morphology and physical strength were superior to those of single-layered composites. The prepared polymeric films consist of a dense bottom layer and a CAYS-holding top layer. The former is made of coagulating the polysulfone and methylene chloride binary solution and works as a supporter to improve the composite's physical strength, while the latter holding the inorganic fluor plays a role as an active site to detect the radioactive contamination. The prepared films revealed two distinguished, but tightly attached, double layers, their attachment being identified by morphology of the interface between two layers. As prepared by water immersion coagulation, the films have highly developed macropores, compared with a dense structure in the film prepared by evaporation. In the radionuclide detection test of the CAYS-impregnated composites, the films have reliable detection capacity at a radionuclide spotting test. The double-layered composites with the dense support layer show a better stability in holding the radionuclides spotted on the surface as well as an improvement in physical strength, compared with the single-layer composites having shortcomings such as being too porous or being brittle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.99-99
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• 2010

Polymer nanocomposite has been attracting much attention as a new insulation material, since homogeneous dispersion of nm-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy based nanocomposites were made and AC breakdown strength of Nano-TiO2 and micro-silica filler mixture of epoxy based composites were studied by sphere to sphere electrode. Moreover, nano- and micro-filler combinations were adopted as an approach toward practical application of nanocomposite insulation materials. Nano-TiO2 particle size is about 10nm and composites ratio was resin (100) : hardener (82) : accelerator (1.5). AC breakdown test was performed at room temperature (25 [$^{\circ}C$], 80 [$^{\circ}C$] and 100 [$^{\circ}C$] in the vicinity of Tg (90[$^{\circ}C$]). And thermal conductivity were measured by ASTM-D5470.

• Macromolecular Research
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• v.12 no.5
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• pp.443-450
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• 2004

We have studied the effects that inorganic zeolite powder have on structurally different copolymer [poly(propylene-co-ethylene)] and terpolymer [poly(propylene-co-ethylene-co-l-butene)] systems and the possibility of preparing suitable porous composite films. The impact strength and yield stress of the composites did not improve upon any further loading of zeolite, but the modulus increased gradually with respect to the filler loading. The experimental modulus of each of the two systems was compared with theoretical models. We performed a morphological study of the filler mixing efficiency and image analysis. The number-, weight-, and z-average air hole diameters were compared with respect to the draw ratio as well as the zeolite loading. The experimental results suggest that these two matrices can provide a new choice for preparing future multiphase polymeric porous films by stretching them unidirectionally. In particular, we suggest that a 40 wt% zeolite loading at a draw ratio of 4 is useful for porous film applications.

• Journal of Hydrogen and New Energy
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• v.25 no.1
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• pp.28-38
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• 2014

The organic-inorganic composite membrane in polymer exchange membrane fuel cells (PEMFCs) have several fascinating technological advantages such as a proton conductivity, thermal stability and mechanical properties. As the inorganic filler, silicon carbide (SiC) fiber have been used in various fields due to its unique properties such as thermal stability, conductivity, and tensile strength. In this study, composite membrane was successfully fabricated by modified-silicon carbide fiber. Modified process, as a novel process in SiC, takes reaction by phosphoric acid after oxidation process (generated homogeniusly $SiO_2$ layer on SiC fiber). The mechanical property which was conducted by tensile test of the 5wt% modified-$SiO_2@SiCf$ composite membrane was better than that of Aquivion casting membrane as well as ion cxchange capacity(IEC) and proton conductivity. In addition, the single cell performance was observed that the 5wt% modified-$SiO_2@SiCf$ composite membrane was approximately $0.2A/cm^2$ higher than that of a Aquivion casting electrolyte membrane and electrochemical impedance was improved with the charge transfer resistance and membrane resistance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.66-71
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• 2011

Biocomposites were fabricated with biodegradable polymers and natural fibers. Biocomposites have benefits of low cost, low density, and biodegradability over inorganic fiber composite, and give comparable strength properties. Hydrophobic polymer used for sizing in paper industry, AKD (Akenyl Keten Dimer), was applied to natural fibers, red algae fibers (RAF) in this study, to make fiber surfaces more compatible to hydrophobic nature of matrix polymers. Composites with RAF, kenaf, glass fibers, and carbon fibers have been fabricated by a compression molding method and their thermo-mechanical properties have been studied. Also, the thermal dimensional stability test was done from at 30 to $100^{\circ}C$. The storage moduli and the thermo-mechanical stabilities of polypropylene and poly lactic acid based biocomposites were improved by reinforcing with the RAF and much more with AKD treated fibers. Dimensional stability of biocomposite was also markedly improved by AKD pretrement on RAF.