• 제목/요약/키워드: Physical and chemical properties

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Synthesis of Acrylic Resins for High-Solid Coatings Containing Acetoacetoxy Group (Acetoacetoxy기 함유 하이솔리드 도료용 아크릴 수지의 합성)

  • You, Hyuk-Jae;Chung, Dong-Jin;Jung, Choong-Ho;Hahm, Hyun-Sik;Park, Hong-Soo;Kim, Tae-Ok
    • Journal of the Korean Applied Science and Technology
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    • v.20 no.3
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    • pp.221-229
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    • 2003
  • A copolymer ${\sim}$550cps ; $M_n$, 2590${\sim}$2850 ; and conversion, 82${\sim}$89%, respectively. It was found from the plotting of $T_g$ versus viscosity and $T_g$ versus molecular weight that viscosity increased with $T_g$ while number averaged molecular weight decreased with increasing $T_g$.

The Effect of Crosslink Structures on the Physical Properties of Carbon Black Filled NR and SBR Vulcanizates (가황(加黃)고무의 물리적(物理的) 성질(性質)에 미치는 가교구조(架橋構造)의 영향(影響))

  • Kim, Sang-Goo
    • Elastomers and Composites
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    • v.23 no.4
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    • pp.299-307
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    • 1988
  • The mono-, di- and polysulfidic concentrations of the carbon black filled NR and SBR vucanizates which have different cure systems were determined. The n-decane was used as a swelling solvent. The propane-2-thiol and hexane thiol were used as specific chemical probes to cleavage the chemical crosslinks such as di- and polysulfide. In order to understand the effect of crosslink structure on the physical properties of vulcanizates, the tensile properties, fatigue failure, heat build up, compression set and viscoelastic properties were measured. From the results, the significant relationships between crosslink sturctures and physical properties, especially a gins resistance were obtained. Therefore, the better performances of the product can be satisfied by using the interpretations and approaches in this study.

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Physical and Chemical Properties of Silk Fiber Treated with Calcium Nitrate (질산칼슘 처리농도에 따른 수축견사의 이화학적 특성)

  • 이광길;이용우
    • Journal of Sericultural and Entomological Science
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    • v.40 no.1
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    • pp.70-77
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    • 1998
  • This study was carried out in order to find out the relationship between physical and chemical properties of silk fiber treated by concentrated calcium nitrate solution. The tensile, thermal and dynamic mechanical properties are also examined on Ca(NO3)2 treated silk fibers. The tensile properties of silk fibers treated by calcium nitrate changed with a concentration. The thermal behavior were also affected by the concentration of calcium nitrate. The degradation temperature (endotherms) and glass transition temperature shifted to lower temperature as the treated concentration increased. It is thought that the physical properties are strongly related to the structure and morphology of Ca(NO3)2 treated silk fibers. As a result, these give property changes with a concentration dependence.

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Comprehending Polymer-Clay Nanocomposites and Their Future Works (고분자-점토 나노복합체 이해와 향후 연구 방향)

  • Choi, Yeong Suk;Chung, In Jae
    • Korean Chemical Engineering Research
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    • v.46 no.1
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    • pp.23-36
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    • 2008
  • Polymer-clay nanocomposites, a novel organic-inorganic hybrid, attract much attention from both scientific fields and engineering fields due to their balanced improvements in mechanical properties as well as diffusion behaviors, including flame-retarding and barrier properties, with small amounts of clay. Preparation of polymer-clay nanocomposites, summarized as a process for uniform dispersion of hydrophilic layered clays in hydrophobic polymer matrixes, includes several technologies and scientific phenomena, such as surface-modifications of clay layers, physical properties of clays in liquids and dried states, polymer synthesis, polymer rheology, behaviors of polymer solutions/or monomers in the confined geometry, mechanical properties of polymers and clays. To comprehend complicated physical/chemical phenomena involved in the fabrication of nanocomposites, we reviewed physical properties of clays, structures of clays in nanocomposites, characterization of nanocomposites, the relation between morphology and physical property of nanocomposites, surveyed recent research trends, and then suggested a few strategies or methods for fabrication of nanocomposites reflecting future research directions.

Influence of Blending Method on the Generation of Wear Particulate Matters and Physical Properties in TBR Tire Tread Compounds

  • Sanghoon Song;Junhwan Jeong;Jin Uk Ha;Daedong Park;Gyeongchan Ryu;Donghyuk Kim;Kiwon Hwang;Sungwook Chung;Wonho Kim
    • Elastomers and Composites
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    • v.58 no.4
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    • pp.161-172
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    • 2023
  • Because particulate matter has emerged as a major contributor to air pollution, the tire industry has conducted studies to reduce particulate matters from tires by improving tire performance. In this study, we compared the conventional blending method, in which rubber, filler, and additives are mixed simultaneously, to the Y-blending method, in which masterbatches are blended. We manufactured carbon black (CB)-filled natural rubber (NR)/butadiene rubber (BR) blend and silica-filled epoxidized NR/BR blend compounds to compare the effects of the two blending methods on the physical properties of the compounds and the amount of particulate matter generated. The Y-blending method provided uniform filler distribution in the heterogeneous rubber matrix, improved processability, and exhibited low rolling resistance. This method also improved physical properties owing to the excellent filler-rubber interaction. The results obtained from measuring the generation of particulate matter indicated that, the Y-blending method reduced PM2.5 particulate matter generation from the CB-filled and silica-filled compounds by 38% and 60%, and that of PM10 by 29% and 67%, respectively. This confirmed the excellence of the Y-blending method regarding the physical properties of truck bus radial tire tread compounds and reduced particulate matter generated.

Physical and Rheological Properties of Thermoplasticized Crosslinked-Polyethylene Foam in Supercritical Methanol

  • Cho, Hang-Kyu;Hong, Soon-Man;Baek, Kyung-Yeol;Koo, Chong-Min;Lee, Hong-Shik;Lee, Youn-Woo
    • Macromolecular Research
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    • v.17 no.12
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    • pp.950-955
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    • 2009
  • The physical and rheological properties of thermoplasticized irradiation-crosslinked polyethylene foam using supercritical methanol treatment were investigated by GPC, FTIR, DSC, WAXS, DMTA and UDS. The polyethylene foam was selectively decrosslinked into thermoplasticized polyethylene in an appropriate supercritical methanol condition without any undesirable side reactions such as oxidation and disproportionation. The thermoplasticization was promoted with increasing reaction temperature to reach completion above $380^{\circ}C$. The supercritical reaction condition affected the crystallization behavior, and mechanical and rheological properties of the decrosslinked polyethylene foam, but not its crystallographic structure or crystallinity.

The Calculation of Physical Properties of Amino Acids using Molecular Modeling Techniques

  • Ui-Rak Kim;Kyung-Sub Min;Bong-Jin Jeong
    • Bulletin of the Korean Chemical Society
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    • v.15 no.2
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    • pp.106-112
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    • 1994
  • Six physical properties (molecular weight, heat capacity, side chain weight, side chain volume, standard entropy and partial molar volume) of amino acids, peptides and their derivatives were examined by molecular modeling techniques. The molecular connectivity index, Wiener distance index and ad hoc descriptor are employed as structural parameters to encode information about branching, size, cyclization, unsaturation, heteroatom content and polarizability. This paper examines the correlation of the molecular modeling techique's parameters and the physicochemical properties of amino acids and their derivatives. As a result, calculated values were in agreement with experimental data in the above six physical properties of amino acids, peptides and their derivatives and the molecular connectivity index was superior to the other indices in fitting the calculated data.

Fabrication of Nanocomposite Powders by Sonochemical Method

  • Hayashi, Yamato;Sekino, Tohru;Niihara, Koichi
    • Journal of Powder Materials
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    • v.8 no.3
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    • pp.207-209
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    • 2001
  • Nano particles have recently been a major research interest, motivated by their unusual physical and chemical properties. Such particles can be synthesized using physical and chemical methods. The physical methods need expensive installation like vacuum induction furnace, whereas in chemical methods the process in generally very simple and low cost. In this study, simple and new fabrication process by using ultrasound was investigated to prepare the nano-sized metal particles on various powders at room temperature.

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Effect of Low Temperature Heat Treatment on the Physical and Chemical Properties of Carbon Anode Materials and the Performance of Secondary Batteries (저온 열처리가 탄소 음극재의 물리·화학적 특성 및 이차전지 성능에 미치는 영향)

  • Whang, Tae Kyung;Kim, Ji Hong;Im, Ji Sun;Kang, Seok Chang
    • Applied Chemistry for Engineering
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    • v.32 no.1
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    • pp.83-90
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    • 2021
  • In this study, effects of the physical and chemical properties of low temperature heated carbon on electrochemical behavior as a secondary battery anode material were investigated. A heat treatment at 600 ℃ was performed for coking of petroleum based pitch, and the manufactured coke was heat treated with different heat temperatures at 700~1,500 ℃ to prepare low temperature heated anode materials. The physical and chemical properties of carbon anode materials were studied through nitrogen adsorption and desorption, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis. Also the anode properties of low temperature heated carbon were considered through electrochemical properties such as capacity, initial Coulomb efficiency (ICE), rate capability, and cycle performance. The crystal structure of low temperature (≤ 1500 ℃) heated carbon was improved by increasing the crystal size and true density, while the specific surface area decreased. Electrochemical properties of the anode material were changed with respect to the physical and chemical properties of low temperature heated carbon. The capacity and cycle performance were most affected by H/C atomic ratio. Also, the ICE was influenced by the specific surface area, whereas the rate performance was most affected by true density.

Evaluation of Physical and Chemical Properties of Crushed Sand for Highway Construction (고속도로 건설현장에서 사용되는 부순모래의 물리적, 화학적 특성 평가)

  • Lee, Chan-Young;Shim, Jae-Won;Kim, Jin-Cheol;Lee, Byung-Duk
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.141-144
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    • 2006
  • In this study, evaluation of physical and chemical properties of crushed sand was performed to establish optimal mix proportion standard for concrete using crushed sand afterward. Most of properties of crushed sand were satisfied with KS F 2527. Especially, chemical stabilities such as alkali-aggregate reaction were fairly good. However, considerable attention would be required in using crushed sand from lime stone judging from the result that weight loss of it was more than 23.8%. There were some differences in the properties with production region, stone type and capacity of facility, therefore it is thought that quality should be controled by optimal regulations for corresponding items.

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