• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.379-383
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• 1977

Since the organophilic bentonite disperses well in polymer matrix, a composite material of polymer and bentonite was studied for its mechanical properties. To increase the degree of dispersion and the bond in forces to the polymer matrix, bentonite, encapsulated by imidazoline, was used as a filler. Polyethylene powder of particle size of 100 mesh was used, and organophilic bentonite, so-called bentone, whose particle size was 250 mesh was also used in this experiment. V-type mixer was used for mixing and Banbury mixer was used for melt-blending. The sample specimen were made by heating the mixture in the plate press, and the specimen were formed as a sheet, exactly the same as the mold on the plate. Tensile strength, bending strength and compressive strength were studied specially. Tensile strength, elongation rate, bending strength and bending rate at constant pressure were decreased as the filler content increased. Compressive strength was increased as the filler content increased.

• Elastomers and Composites
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• v.43 no.3
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• pp.183-190
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• 2008

In this study, we have investigated mechanical properties and scratch resistance of polypropylene compounds by two types of masterbatch with different molecular weight of PP. Masterbatches were prepared with polypropylene(PP) and polydimethylsiloxane(PDMS) by melt mixing. Mechanical properties and scratch behavior were examined with UTM and polarizing microscope. The morphology surface of grain pattern was investigated Color 3D Laser Scanning Microscope. Mechanical properties of two masterbatches containing PP compounds showed a little bit difference in accordance with amount of M/B. Scratch resistance was much improved by adding masterbatches used high-molecular weight PP. Scratch resistance was excellent when grain pattern of the surface is deep, large, round and irregular.

• Journal of Welding and Joining
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• v.25 no.3
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• pp.64-71
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• 2007

The dissolution phenomenon of the solid phase powder and base metal by liquid phase insert metal during Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111(base metal) powder and the GNi3 (Ni-l4Cr-9.5Co-3.5Al-2.5B) powder was investigated. In case of the mixed powder contains modified GTD111 powder 50wt%, all of the powder was melted by liquid phase at 1423K. At the temperature between solidus and liquidus of GNi3, liquid phase penetrated into the boundary of the modified GTD111 powder and solid particle separated from powder was melted easily because area of reaction was increased. With increasing mixing ratio of the modified GTD111, it needed the higher temperature to melt all of the modified GTD111 powder. During Transient Liquid Phase bonding using the mixed powder composed of the modified GTD111 50wt% and GNi3 50wt% as insert metal, width of the bonded interlayer was increased with increasing bonding temperature by reaction of the base metal and liquid phase in insert metal. Dissolution of the base metal and modified powder by liquid phase progressed all together and after all of the powder was melted nearly, the dissolution of the base metal occurred quickly.

• Polymer(Korea)
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• v.26 no.1
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• pp.37-44
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• 2002

The polymer blends of waste polyvinyl chloride (RPVC) and waste polyethylene(RPE) were prepared by melt mixing, and their morphology and tensile properties were evaluated after the copolymers having an ethylene group in backbone and ester group in side position were added as comptatibilizers. The blend compositions were varied as follows ; RPVC/RPE 85/15 wt%, where RPVC formed a continuous phase : 50/50, mid composition : 15/85, RPE a continuous phase. The blends revealed a very low compatibility between component polymers because they showed domain sizes greater than $10\mu\textrm{m}$ over all compositions, especially the worst compatibility around mid composition. The blends showed higher compatibility when ethylene vinylacetate copolymer(EVA) and ethylene ethylacrylate-graft-methyl methacrylate copolymers(EEA-MMA) were added.

• Polymer(Korea)
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• v.28 no.6
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• pp.460-467
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• 2004

The polymer blends of waste poly(vinyl chloride) (RPVC) and waste polyethylene (RPE) were prepared by melt mixing. Their morphologies and rheological properties were investigated and torque changes were also measured. Comparing the torques calculated by the log additivity rule with measured torque changes, the polymer blends showed the large negative deviation behavior (NDB) due to their incompatibility. The shear viscosities of the blends decreased with increasing shear rates, showing shear thinning behavior. The shear viscosity of the blends with compatibilizer was larger than that of the blends without compatibilizer. SEM micrographs of the strands after measurement showed that the domain size of the blends was slightly enlarged with increasing the shear rate. Also, RPVC domain size was larger in the core-sections of the strands from capillary viscometer than in the surface region.

• Elastomers and Composites
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• v.35 no.2
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• pp.149-156
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• 2000

trans-octylene rubber(TOR) was melt-blended with an incompatible NBR/EPDM (70/30) blend. Mixing torque and temperature were reduced as TOR was added to the NBR/EPDM blend. Rheometer results indicated that TOR participated in vulcanization and became a part of network. A scanning electron micrograph demonstrated that EPDM was dispersed in NBR matrix in the blend and the addition of TOR led to a finer dispersion of EPDM particles. On the addition of TOR, the tensile strength, the tensile strain as well as the modulus of the blend vulcanizates increased. The ozone resistance of the blends determined in terms of critical stress-strain parameter was significantly enhanced in the blend as TOR was added. Improvements in the properties were believed to be associated with fine morphology and the increase in crosslink density due to the chain entanglement of the ternary blends.

• Polymer(Korea)
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• v.38 no.3
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• pp.327-332
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• 2014

Polymer/wood flour composites are recently attracting a lot of interest because they are economic and ecofriendly. In this study, the effects of wood flour size on the thermal and mechanical properties of a polypropylene/wood flour composite were investigated. Mechanical properties of the composite samples prepared by melt-mixing and compression molding were tested by UTM and an izod impact tester, and thermal properties of them were measured by TGA, DMA, DSC and TMA. The best coupling agent was selected by testing three kinds of maleic anhydride modified polypropylene coupling agents, and under the same condition, the effects of wood flour size on the physical properties of the composite were investigated. According to the test results for four different wood flour sizes of 600, 250, 180 and $150{\mu}m$, flexural strength, flexural modulus, crystallinity and water-resistivity of the composite increased with decreasing wood flour size.

• Composites Research
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• v.16 no.1
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• pp.19-25
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• 2003

In this paper, electrical properties of nanostructured carbon blacks (CB)-filled high density polyethylene (HDPE) composites were investigated as a function of temperature, which were prepared by the conventional melt-mixing method. The composites were irradiated with electron beam in a dosage of 30∼150 kGy to enhance an electronical reproducibility and to reduce a negative temperature coefficient (NTC) phenomenon. And, gel contents (%) of irradiated CB/HDPE composites were estimated by solvent extraction method. From the experimental results. the positive temperature coefficient (PTC) intensity of the composites was strongly depended on the CB content and particle size. And, the increase of gel contents (%) and disappearance of NTC behavior of the composites were identified at a dosage of 60 kGy. It was also found that the electron beam irradiation made an improvement of electrical reproducibility of the composites. This result was probably due to the reduction of the freedom of CB movement at above the melting temperature of the polymer crystalline, resulting in increasing the crosslinking structure of the composites.

• Elastomers and Composites
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• v.45 no.1
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• pp.12-16
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• 2010

In this work, the effect of hydrophobic treated silica on the water absorption, thermal stabilities, and mechanical properties of the epoxy nanocomposites were investigated as a function of the silica content. As filler, fumed silica treated by dimethyldichlorosilane was used. It was found that the silica was well dispersed in the epoxy resins by the melt-mixing method with the addition of a silane coupling agent. The water absorption of the nanocomposites decreased with an increase of the silica content due to the effect of hydrophobic treated silica. The thermal properties, such as thermal degradation temperature, glass transition temperature ($T_g$), and coefficient of thermal expansion (CTE), of the nanocomposites were improved by the addition of silica. Furthermore, the mechanical properties of the nanocomposites, that is, the tensile strength and modulus, were enhanced with increasing silica content. This was attributed to the physically strong interaction between silica and epoxy resins.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.490-494
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• 2011

Nanocomposites of blends of polyethyleneterephthalate (PET) and polyamide66 (Nylon66) containing natural and organically modified montmorillonite clays (PM, $Cloisite^{(R)}$ 25A and 15A) were prepared by melt mixing. DSC results showed that the addition of clay changed the crystallization behavior of PET/Nylon66 nanocomposites. Clay C25A was observed to most significantly change the crystallization temperature than other clays in blends of PET and Nylon66, which may be caused by the difference in interaction with matrix polymers. AFM results also showed that the lowest value of surface roughness was observed for nanocomposites containing C25A indicating the smooth and relatively homogenous surface. Mechanical properties measurement showed the similar results. Contact angle was measured to study the difference in hydrophobicity. An increase in contact angle was observed for nanocomposites with C25A or C15A due to the increased hydrophobicity.