• Geomechanics and Engineering
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• v.33 no.4
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• pp.401-414
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• 2023

Organic clays are ideal habitat for flora and fauna. From a geotechnical perspective, organic clays are soft, weak, variable, heterogeneous and flocculated. Portland cement is a universally common stabiliser. However, some organic acids in soil inhibit full hydration and expose cementation products to rapid dissolution. This paper investigates scopes for use of C₃S cement to enable durable cementation. Prospects of using PP fibre alongside with C₃S cement, scopes for partial replacement of C₃S cement with a plant-based nanosilica and evolution of binders are then investigated. Binding mixtures here mimic the natural functions of rhizoliths, amorphous phases, and calcites. Testing sample population include natural and fibre-reinforced clays, compact mixes of clay - C₃S cement, clay - nanobiosilica, and clay, C₃S cement and nanobiosilica. Benefits and constraints of C₃S cement and fibres for retaining the naturally flocculated structure of organic clays are discussed. Nanobiosilica provides an opportunity to cut the C₃S content, and to transition of highly compressive organic clays into an engineered, open-structured medium with >0.5 MPa compressive strength across the strains spanning from peak to 1.5-times peak.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.144-152
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• 2010

In this study, cement-based filler is used as an adhesive instead of organic adhesive, epoxy because there were problems under wet condition. First, the bond strength of cement-based filler was measured and the result was satisfied with KS F 4716. However, in case of wet condition, bond strength of epoxy adhesive decreased $0.73N/mm^2$ in 7 days and $0.84N/mm^2$ in 14 days from pilot test. This implies that there would be a problem on reinforced concrete structure in wet condition, such as tunnel and sewage box. In the second experiment, the flexural strength of RC beams with GFRP using different thickness of cement-based filler was investigated, and the result was indicated 113%, 66%, 75% increase in 10mm, 20mm, 30mm thickness, respectively. From the result, it was known that 10mm filler thickness produces stable bond performance.

• Korean Journal of Materials Research
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• v.22 no.11
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• pp.604-608
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• 2012

Recently, inorganic-organic hybrid materials have attracted much attention not only for their excellent thermal conductivity but also for their flame retardant properties. In this study, the properties of organic-inorganic hybrid insulating materials using inorganic fillers and polyurethane foam with different foaming conditions have been investigated. The addition of 1.5 wt% water to polyurethane as foaming agent shows the best foaming properties. The pore size was decreased in the foaming body with increasing of the $CaCO_3$ addition. The apparent density and thermal conductivity were increased by increasing the $CaCO_3$ addition. With an increasing amount of $CaCO_3$ powder, the flame retardant property is improved, but the properties of thermal conductivity and apparent density tend to decrease. When the addition of fine particles of $CaCO_3$, the apparent density and thermal conductivity were increased and, also, with the addition of coarse particles over $45{\mu}m$ in size, the apparent density and thermal conductivity were increased as well. In this study, the adding of $CaCO_3$ with average particle size of $27{\mu}m$ led to the lowest thermal conductivity and apparent density. After evaluation with different inorganic fillers, $Mg(OH)_2$ showed the highest thermal conductivity; on the other hand, $CaCO_3$ showed the lowest thermal conductivity.

• Korean Journal of Materials Research
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• v.27 no.1
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• pp.12-18
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• 2017

Transparent organic-inorganic hybrid hard coating films were prepared by the addition of $SiO_2$ or $ZrO_2$, as an inorganic filler to improve the hardness property, filler was highly dispersed in the acrylic resin. To improve the compatibility in the acrylic resin, $SiO_2$ or $ZrO_2$ is surface-modified using various silanes with variation of the modification time and silane content. Depending on the content and kind of the modified inorganic oxide, transparent modified inorganic sols were formulated in acryl resin. Then, the sols were bar coated and cured on PET films to investigate the optical and mechanical properties. The optimized film, which has a modified $ZrO_2$ content of 4 wt% markedly improved in terms of the hardness, haze, and transparency as compared to neat acrylate resin and acrylate resin containing modified $SiO_2$ content of 8 wt%. Meanwhile, the low transparency and high haze of these films slowly appeared at $SiO_2$ content above 10 wt% and $ZrO_2$ content of 5 wt%, but the hardness values were maintained at 2H and 3H, respectively, in comparison with the HB of neat acrylate resin.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.654-658
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• 2012

In this work, the properties of an organic-inorganic hybrid insulating material using an inorganic filler and polyurethane foam with different foaming conditions were investigated. At weight ratios of polyol and isocyanate of 1 to 1.2 good foaming properties were noted. In addition, an addition of 0.4 g of water, 0.1 g of surfactant, and 0.1 g of catalyst with respect to the composites of polyol at 5 g and isocyanate at 6 g showed the lowest apparent density and thermal conductivity. The pore size was smaller in the organic-inorganic hybrid foaming body with an increase in the $CaCO_3$ addition amount. Moreover, the apparent density and thermal conductivity were increased when the added amount of $CaCO_3$ increased. Increasing the amount of $CaCO_3$ powder is expected to improve the flame retardant capabilities; however, doing this tends to increase the apparent density and thermal conductivity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.4
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• pp.139-144
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• 2023

Stone papers made of inorganic filler and plastic polymer do not use pulp, which is the main raw material of existing papers, so they contribute to the preservation of nature and can be used as more eco-friendly materials when they have biodegradability. Since most stone papers are manufactured by hot extrusion, the amount of ceramic fillers and related physical properties are limited to control manufacturing workability. In this study, the stone paper composition was prepared in a liquid form using solvents, so that there was little limitation on the amount of ceramic filler added and it was also easy to add additives to control biodegradability. They were fabricated from eco-friendly raw materials using waste oyster shells as an inorganic filler and (recyclable) PVC materials as an organic binder. After making a solution using common solvents for PVC, inorganic filler and cellulose to impart biodegradability were mixed and processed into sheets to prepare solvent-based stone papers, and their paper properties were evaluated.

• Polymer(Korea)
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• v.27 no.6
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• pp.589-595
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• 2003

Unsaturated polyester (UP) nanocomposite with montmorillonite (MMT) which contains different types of organic modifiers far nano-filler have been prepared to investigate the effect of chemical structure of organic modifiers and mixing time of all components on properties of products. It was found that the morphology and various physical properties of UP/MMT nanocomposites were influenced by properties of organic modifiers of MMTs. It was also confirmed that the content of MMT does not significantly affect properties of UP/MMT nanocomposites.

• Polymer(Korea)
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• v.29 no.2
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• pp.161-165
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• 2005

$\alpha,\omega-Vinyl$ poly(dimethyl-methylphenyl) siloxane propelymer (VPMPS ) was prepared by the equilibrium polymerization of octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane $(D_3^{MePh})$, and 1,1,3,3-tetramethyl-1,3-divinylsiloxane (MVS) as end-blocker. And also, $\alpha,\omega-hydrogen$ poly(dimethyl-methyltrifluoropropyl)siloxane prepolymer (HPDMFS) was prepared from $D_4$, 1,3,5-trimethyl-1,3.5-trifluoropropylcyclotrisiloxane $(D_3^{MeF3P})$, and 1,1,3,3-tetramethyldisiloxane. Poly(organosiloxane) rubber composite containing high thermal conductive filler was prepared by compounding VPMPS, HPDMFS, spherical alumina, and catalyst in high speed dissolver. The crosslinking density of poly (organosiloxane) composite was measured by oscillation rheometer. Poly(organosiloxane) composites of TC-POXR-2 and TC-POXR-4 prepared by controlling average diameters of thermal conductive filler, spherical alumina according to Horsfield's packing model were shown to 1.13 W/mK for TC-POXR-2 and 1.19 W/mK for TC-POXR-4.

• Composites Research
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• v.31 no.6
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• pp.412-420
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• 2018

In this work, phenolic resins containing conductive carbon fillers, such as, petroleum coke, carbon black, and graphite, were used to improve the surface heating elements by impregnating a pitch-based carbon paper. The influence of conductive carbon fillers on physicochemical properties of the carbon paper was investigated through electrical resistance measurement and thermal analysis. As a result, the surface resistance and interfacial contact resistivity of the carbon paper were decreased linearly by impregnating the carbon fillers with phenol resins. The increase of carbon filler contents led to the improvement of electrical and thermal conductivity of the carbon paper. Also, the heating characteristics of the surface heating element were examined through the applied voltage of 1~5 V. With the applied voltage, it was confirmed that the surface heating element exhibited a maximum heating characteristic of about $125.01^{\circ}C$(5 V). These results were attributed to the formation of electrical networks by filled micropore between the carbon fibers, which led to the improvement of electrical and thermal properties of the carbon paper.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.1
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• pp.19-27
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• 2022

A series of QPAE/TiO₂-x (x = 1, 4, 7 and 10 wt%) organic/inorganic composite membranes were prepared as electrolyte membranes for alkaline anion exchange membrane fuel cells by controlling the content of inorganic filler with quaternized poly(arylene ether) (QPAE) random copolymer. Among the prepared QPAE/TiO₂-x organic/inorganic composite membranes, the highest ionic conductivity was 26.6 mS cm^-1 at 30℃ in QPAE/TiO₂-7 composite membrane, which was improvement over the ionic conductivity value of 6.4 mS cm^-1 (at 30℃) of the pristine QPAE membrane. Furthermore, the water uptake, swelling ratio, ionic exchange capacity, and thermal property of QPAE/TiO₂-x composite membranes were improved compared to the pristine QPAE membrane. The results of these studies suggest that the fabricated QPAE/TiO₂-x composite membranes have good prospects for alkaline anion exchange membrane fuel cell applications.