• Journal of the Korean Wood Science and Technology
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• 제4권1호
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• pp.28-32
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• 1976

This study was carried out to know the adaptability of barley flour, potato flour and white ash as extender and filler of urea-formaldehyde resin for plywood as a substitute material of wheat flour. The extenders and filler used at this study were extended by several groups of percentages. Shear strength, moisture contents, and specific gravities were compared among tested groups. The results obtained are summarized as follows. 1) Wet and dry shear strength of plywoods extended by 10% barley flour, 30% potato flour, and wheat flours were shown better results than non extended plywoods. 2) There was no significant difference between plywoods extended until 50% barley flours and non extended plywoods. 3) Shear strength of plywoods extended by 50% potato and 100% barley flours were shown worse result than non extended. 4) Dry and wet shear strength of plywoods extended by white ash were shown worst result. 5) The plywoods extended by potato flours were shown not only better shear strength, but also considered more profitable cost for extending.

• Elastomers and Composites
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• 제35권4호
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• pp.303-310
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• 2000

가황천연고무를 제조할 때 가교제와 여러 첨가제의 배합비를 조절하여 그 배합비가 제품의 저온 회복력에 미치는 영향을 검토하였다. 가황천연고무를 200% 신장시킨 후 $-40^{\circ}C$에서 24시간 유지시켜 복원력을 관찰하였다. 일정한 범위에서 황의 함량이 높아질수록, 또한 충전제의 함량은 적을수록 저온회복율은 향상되었다. 가황촉진제, 가소제와 가황촉진조제 등은 일정함량에서 최고치를 나타내었다. 과산화물을 약간 침가하였을 때 저온회복율은 보다 향상되었으나 가황시간은 보다 길어졌다. 최대의 복원력은 85%를 얻을 수 있었다.

• 접착 및 계면
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• 제2권1호
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• pp.1-8
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• 2001

본 연구에서는 슬러지 및 폐타이어 칩(WTC)으로부터 얻은 폐석분을 충전제로 하고 불포화 폴리에스테르 수지(UPE)를 결합재로 하여 고분자 혼성복합재를 제조하였다. 또한 무기 충전제와 매트릭스 사이의 계면 결합뿐만 아니라 매트릭스 내의 충전제의 분산을 향상시키기 위하여 실란[${\gamma}$-methacryloxy propyl trimethoxy silane(${\gamma}$-MPS)]을 이용하여 표면처리를 하였다. 혼성복합재의 구조적 특성과 기계적 물성에 대한 이 무기 재활용 충전제의 함량과 농도의 영향은 Mercury Porosimeter 및 주사전자현미경을 이용하여 관찰하였다.

• 한국재료학회지
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• 제19권8호
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• pp.407-411
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• 2009

Reflection properties, such as specular reflection and diffuse reflection, are very important optical properties for the reflector, which has high reflectance in the display and architecture industry. Calcite is lowcost, nontoxic, and stable over a wide temperature range. Therefore, it is one of the most widely using fillers in many industries and has some advantages over titania as a filler to improve reflectance. However, optical properties, especially those of ceramic-filled composites, have not been analyzed. We studied the reflectance of calcite composites with their surface roughness. The reflectance of the composites was determined using a UV-visible spectrometer. The surface morphology and the micro-structure of the composites were investigated by atomic force microscope. The reflectance of the composites was improved by increasing the content of calcite in the calcite-frit composite. The reflectance is related with the surface roughness in the composites. However, the reflectance depends on the calcite contents in materials with similar surface roughness.

• 한국세라믹학회지
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• 제49권6호
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• pp.625-630
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• 2012

Highly porous silicon carbide (SiC) ceramics were fabricated from polysiloxane, SiC and carbon black fillers, AlN-$Y_2O_3$ additives, and poly (ether-co-octene) (PEOc) and expandable microsphere templates. Powder mixtures with a fixed PEOc content (30 wt%) and varying SiC filler contents from 0-21 wt% were compression-molded. During the pyrolysis process, the polysiloxane was converted to SiOC, the PEOc generated a considerable degree of interconnected porosity, and the expandable microspheres generated fine cells. The polysiloxane-derived SiOC and carbon black reacted and synthesized nano-sized SiC with a carbothermal reduction during a heat-treatment. Subsequent sintering of the compacts in a nitrogen atmosphere produced highly porous SiC ceramics with porosities ranging from 78 % to 82 % and a flexura lstrength of up to ~7 MPa.

• 한국주조공학회지
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• 제19권5호
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• pp.419-426
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• 1999

Hardening behavior and metal-mold reaction of phosphate bonded investments for titanium and titanium alloys were investigated. Alumina and $Y_2O_3-stabilized$ zirconia, which are thermodynamically more stable than Titania, were used as major filler materials. $NH_4H_2PO_4$ was used as binder, and MgO was used as hardening acceleration material. A different composition ratio of binder and hardening acceleration material had effected on general hardening behavior and castings. And adding $YO_3-stabilized$ zirconia to alumina, metal-mold reaction characteristics for castings was evaluated. Considering working conditions and effects on castings, the best composition ratio conditions were both 10:10 and 12:8($NH_4H_2PO_4vs.\;MgO$). On the other hand, increasing the contents of $Y_2O_3-stabilized$ zirconia for filler material, metal-mold reaction layer of titanium castings was greatly decreased.

• 전기학회논문지
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• 제67권9호
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• pp.1181-1188
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• 2018

In order to develop new insulating materials for GIS Spacer using environmentally friendly insulating gas, three kinds of dispersed liquid nano composites of solid epoxy /nano layered silicate filled material were prepared. And the epoxy/nano/micro silica composite was prepared by mixing epoxy/nano 3 phr dispersion/4 kinds of filler contents(40,50,60, 70wt%). The electrical insulation breakdown strengths of the nano and nano/micro mixed composites were evaluated by using 8 kinds of samples including the original epoxy. The mechanical tensile strength of the epoxy / nano / micro silica composite were evaluated, also. The TEM was measured to evaluate the internal structure of nano/micro composites. As a result, it was confirmed that the layered silicate nano particles was exfoliated through the process of inserting epoxy resin between silicate layers and the layers. In addition, dispersion of nano / micro silica resulted in improvement of electrical insulation breakdown strength with increase of filling amount of dense tissue with nanoparticles inserted between microparticles. In addition, the tensile strength showed a similar tendency, and as the content of microsilica filler increased, the mechanical improvement was further increased.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.930-935
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• 2005

In order to synthesis of the materials and modulus for floor impact sound reduction, we investigated effect on dynamic elastic modulus of floor impact sound reduction materials and module made by inorganic porous materials, EVA chips and so on. We find correlation property between dynamic elastic modulus and light-weight impact noise. And we measured the dynamic elastic modulus of materials and module for floor impact sound reduction. And we predicted reduction efficiency on floor Impact Noise of those. The dynamic elastic modulus is reduced by increase of filler contents and filler species. When the materials for floor impact sound reduction is consisted of l5wt% EVA Chip and l5wt% inorganic porous materials, its dynamic elastic material is the lowest. And when the module is consisted of PE (upper side), PS embossing board(lower side) and the materials for floor impact sound reduction(middle), its dynamic elastic material is the lowest.

• 한국레이저가공학회지
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• 제14권4호
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• pp.1-8
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• 2011

This study is about laser welded joints in order to replace the traditional screw connection of a differential gear and its case in the differential gear assembly. Screws are usually used to join these parts. But the screws take up weight and space. So we needed to improve the joining method. In the welding of a differential gear and its case, the quality is much harder to control, because the high carbon contents of the two components results in cold cracks. But a new method that adds wire allows these materials to be joined. Additionally, more distortions generally occurs in the welded joints than in screws. We tried to prove that laser welding is an available method for joining these parts through the measurement and various tests.

• 접착 및 계면
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• 제15권1호
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• pp.9-13
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• 2014

본 연구는 폴리프로필렌/마이카 복합재료의 고상압출에 의한 배향에 따른 기계적 물성의 변화에 관한 연구이다. 마이카 함량이 증가할수록 복합재료의 비중이 증가하였다. 하지만 고상압출에 따른 배향에 의해 복합재료의 비중은 미세공극의 발생으로 말미암아 비중은 배향 전에 비해 현저히 감소하는 것으로 나타났다. 이러한 미세공극의 존재는 복합재료의 인장 및 굴곡물성에 큰 영향을 미치는 것으로 나타났다. 고상압출 여부에 관계없이 마이카 함량이 10 wt%일 때 최대 굴곡 물성이 관찰되었다.