• Title/Summary/Keyword: Polyolefin

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Polymerizations of Propylene with Unsymmetrical ($\alpha$-Diimine)nickel(II) Catalysts

  • Jeon Man-Seong;Han Chul-Jong;Kim Sang-Youl
    • Macromolecular Research
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    • v.14 no.3
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    • pp.306-311
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    • 2006
  • New unsymmetrical ($\alpha$-Diimine)nickel(II) catalysts having different pendent groups at the ortho positions on aromatic rings were synthesized and subjected to propylene polymerizations with MAO (methylaluminoxane). Structural analyses of the resulting polypropylenes by $^1H\;and\;^{13}C\;NMR$ showed that the ortho substituents on aromatic rings of ($\alpha$-diimine)nickel(II) catalyst affected significantly the polypropylene microstructure. While $C_s$ symmetric catalyst afforded a syndiotactic polypropylene (rr triad content=66%) due to the syndiospecific chain end control, $C_1$ symmetric catalysts produced much less stereoregular polypropylenes (rr triads content <50%), presumably because of collision of the isospecific site control with the syndiospecific chain end control.

A New Sample Preparation Technique for SEM Observation of Polyolefin Microstructure (주사전자현미경상에서의 고분자 미세구조 관찰)

  • Park, Je-Myung
    • Applied Microscopy
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    • v.29 no.4
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    • pp.405-415
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    • 1999
  • In general, transmission electron microscopy (TEM) is usually used in the investigation of polymer microstructure. Microtoming, solution casting, staining and carbon replica method are frequently introduced to the study of the polymer morphology with TEM, however the sample preparation procedure of those techniques is very difficult, and it takes a long time. The purpose of this study is to develop a new sample preparation technique which is suitable for the investigation of the various shapes and species of polyolefin microstructure by scanning electron microscopy (SEM). By modifying the conventional chemical etching method, we developed a new chemical etching technique and sample preparation procedure that are suitable for SEM study of polymer microstructure. In this study the permanganate etching method is introduced and the optimum etching condition are determined by simply adjusting the etchant formulation, concentration and etching time. This technique has shown good reproducibility and it's morphological results agree well with other works on various types of microstructures such as spherulite characterization of isotatic polypropylene $(\alpha/\beta)$, polyethylene and poly-propylene copolymer characterization, and the study of lamellar growth pattern of unsheared or oriented materials. This technique has also been applied to the industrial fields for characterization of the polyolefin film, automobile products and the others.

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Preparation and Characterization of Sulfonated Poly (Arylene Ether Sulfone) Random Copolymer-Polyolefin Pore-filling Separators with Metal Ion Trap Capability for Li-ion Secondary Battery (리튬이온 이차전지용 금속이온 선택성 술폰화 폴리아릴렌에테르술폰 공중합체-폴리올레핀 함침격리막 제조 및 특성)

  • Jeong, Yeon Tae;Ahn, Juhee;Lee, Chang Hyun
    • Membrane Journal
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    • v.26 no.4
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    • pp.310-317
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    • 2016
  • Lithium ion secondary battery (LISB) is an energy conversion system operated via charging-discharging cycle based on Lithium ion migration. LISB has a lot of advantages such as high energy density, low self-discharge rate, and a relatively high lifetime. Recently, increasing demands of electric vehicles have been encouraging the development of LISB with high capacity. Unfortunately, it causes some critical safety issues. It includes dendrite formation on negative electrode, resulting in electric shortage problems and battery explosion. Also, the elevated temperatures occurred during the LISB operation induces thermal shrinkage of polyolefin (e.g., polyethylene and polypropylene) separators. Consequently, the low thermal stability leads to decay of LISB performances and the reduction of lifetime. In this study, sulfonated poly (arylene ether sulfone) (SPAES) random copolymers were used as key materials to prepare polyolefin pore-filling separator. The resulting separators were evaluated in the term of metal ion chelation capability associated with dendrite formation, $Li^+$ ion conductivity and thermal durability.

Adhesion Properties of Hot-Melt Pressure Sensitive Adhesives Based on Metallocene Polyolefin (메탈로센 폴리올레핀을 이용한 핫멜트 점착제의 제조 및 특성)

  • Shim, Jaeho;Sung, Ickkyeung;Lee, Jungjoon
    • Journal of Adhesion and Interface
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    • v.14 no.2
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    • pp.95-100
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    • 2013
  • In this study, a series of hot-melt pressure sensitive adhesives (HMPSAs) based on metallocene polyolefin (me-PO) were prepared to investigate their possibility of replacing the HMPSAs based on styrenic block copolymers (SBCs). In addition, to optimize the performance of HMPSAs based on me-PO, several tackifiers having different softening point and molecular weight were evaluated. To achieve the HMPSAs which can satisfy the Dahlquist Criterion, hot melts required over 10% of process oil. To obtain the HMPSAs having low viscosity which can be applied by a spraying type applicator, secondary polymer having relatively low crystallinity was required. And, tackifier having high molecular weight attributed to increasing the cohesive strength of me-PO based HMPSAs.

A Study on the Dielectric Characteristics of Non-Cross Linked Polyolefin for Distribution Power Cables (배전용 전력 케이블을 위한 비-가교 폴리올레핀 재질의 절연특성 연구)

  • Kim, Junil;Lee, Onyou;Bang, Seungmin;Kang, Jong O;Lee, Hongseok;Jeong, Yeong-Ho;Kang, Hyoungku
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.4
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    • pp.373-377
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    • 2014
  • A cross linked polyethylene (XLPE) material has been widely used to develop a distribution power cable due to its excellent electrical characteristics and mechanical strength. However, several problems such as environmental disruption, electrical aging, thermosetting property, and impurities which cause degradation also arise. Therefore, a novel dielectric material should be developed to substitute for the XLPE. Several kinds of polyolefin materials to substitute for the conventional dielectric material, XLPE are developed and A cylindrical rod to cylindrical rod electrode system made with stainless steel is used to perform the experiments according to the ASTM D-149 protocol under an AC and Impulse input voltage condition. The experimental results are calculated by the Weibull distribution method and analyzed by an Finite Element Method(FEM). Finally, the dielectric characteristics of the conventional XLPE and novel polyolefin are experimented compared with each other in this study.

Toughening Mechanism and Mechanical Property in Thermoplastic Polyolefin-Based Composite Systems (폴리올레핀 복합재료의 파괴인성 메커니즘 및 기계적 특성)

  • Weon, Jong-Il
    • Polymer(Korea)
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    • v.31 no.2
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    • pp.123-129
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    • 2007
  • Toughening mechanisms and mechanical properties of three different polyolefin-based composite systems we studied using the tensile, Izod impact and double-notch lout-point-bending (DN-4PB) test, which is well known be an effective tool for probing the failure mechanism (s) around the subcritically propagated crack tip. Microscopy observations such as optical microscopy and transmission electron microscopy were carried out lot the test samples. A detailed investigation clearly shows that a variety of toughening mechanisms, i.e., shear yielding, craze, particle-matrix debonding, rubber particle cavitation, crack deflection and bifurcation, are observed around crack tip damage zone. These toughening mechanisms are responsible for the observed, improved fracture toughness. Based on this study, DN-4PB technique is sufficient to obtain the information needed to describe the fracture behavior of polyolefin-based composites as well as their corresponding toughening mechanisms.

Study on the Properties of Polyolefin Elastomer(POE)/Ethylene Vinylacetate(EVA) Film with the Conent of Compatibilizer (POE-g-MAH) (상용화제(POE-g-MAH) 함량에 따른 Polyolefin elastomer/Ethylene vinylacetate 필름의 물성 변화에 대한 연구)

  • Na Young Jang;Eun Hye Kang;Jeong Jin Park;Gyeong Cheol Yu;Jong Hee Kim;Seung Goo Lee
    • Textile Coloration and Finishing
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    • v.35 no.3
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    • pp.159-168
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    • 2023
  • Polyolefin elastomer (POE) is widely used in a variety of applications, particularly in the manufacture of composites, due to its excellent mechanical properties, chemical resistance, and flexibility. However, POE has a high processing temperature, which causes damage to the fiber during the manufacturing process when impregnating the fiber. Therefore, ethylene vinylacetate (EVA), which has a low melting point and excellent adhesion properties, is blended with POE to reduce the processing temperature, and POE-g-MAH (Polyolefin elastomer-grafted-maleic anhydride) is used as a compatibilizer to further improve the POE/EVA blend properties. The compatibility of POE/EVA blends is observed by SEM, and the interaction between each polymer is confirmed by DSC and FT-IR. In addition, the effect of adding the compatibilizer is analyzed through mechanical properties such as tensile strength and elongation. The optimal content of compatibilizer for POE/EVA blends considering physical properties and moldability is sought, and 20 phr is determined to be the most appropriate.

Synthesis of Super Hydrophobic Disazo Red Dyes using Alkylanilines as Diazo Components (알킬아닐린을 디아조성분으로 활용한 디스아조계 초소수성 적색염료의 합성)

  • Kim, Taekyeong;Ryu, Myeonghwa;Jang, Youngjae
    • Textile Coloration and Finishing
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    • v.27 no.1
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    • pp.27-34
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    • 2015
  • Novel super hydrophobic disazo red dyes were synthesized to improve light fastness of the primary monoazo red dye of previous study on polyolefin fibers such as polypropylene and ultra high molecular weight polyethylene fibers. 4-Alkylanilines were diazotized and then coupled to 2,5-dimethylaniline to produce dye intermediates which were then further used to synthesize final disazo red dyes by diazoization and coupling to ${\beta}$-naphthol. Considering both affinity of the dyes toward both polyolefin fibers and color fastnesses, the decyl-substituted dye was determined as the optimum dye. The decyl-substituted disazo red dye exhibited good dyeability on both polyolefin fibes and almost the same color values as the previous primary monoazo red dye. Light fastness on ultra high molecular weight polyethylene fibers was improved up to rating 3~4 compared to rating 2~3 of the previous primary monoazo red dye.

Coordination Polymerization of Carbon Double Bond Catalyzed by Organometallic Compounds (유기금속화합물 촉매에 의한 탄소이중결합의 배위중합)

  • Lee Dong-ho
    • Polymer(Korea)
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    • v.29 no.4
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    • pp.321-330
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    • 2005
  • In 1990's the Korean polyolefin industry boomed up through the development of magnificient polymerization catalysts. To understand the general situation of polymerization catalyst R & D, the various experimental results had been summarized for the investigation of not only the supported Ziegler-Natta catalyst used presently in polyolefin industry but also the metallocene catalysts applied for the preparation of special grade of polyolefin. In addition, it had been shown that the new polymeric materials were prepared by new developed catalyst, and the polymer in-situ nanocomposites could be obtained with the application of catalyst heterogenization procedures.

Study on the Safety of Playground Flooring Made of Polyolefin Foam Waste and Rubber Paving (폐폴리올레핀 폼과 탄성 포장재로 구성된 어린이 놀이터 바닥의 안전성에 관한 실험적 연구)

  • Choi, Soo-Kyung;Jun, Myoung-Hoon;Lee, Do-Heun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.3
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    • pp.246-254
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    • 2013
  • This study is purposed to verify the safety of the floor of the children's playground using polyolefin foam waste and rubber paving. The critical fall height, walking suitability, long term physical fatigue expectation and slipperiness were tested. Polyolefin foam wastes in thickness of 30mm, 50mm and 70mm were prepared with paving the rubber paving materials in 12mm and 15mm thickness respectively. The test on the critical fall height was carried out according to KS G 5758:2009. The floor hardness test equipment (O-Y HMA) was used for the test on hardness of the floor from a viewpoint of walking suitability and fatigue. A portable slipperiness tester (ONO PPSM) was used for slipperiness test. It was revealed from the test that the floor made of the polyolefin foam waste and rubber paving were considerably safe from a viewpoint of impact absorption. With regards to the hardness of the floor, it was shown the excellent performance in the aspects of walking and fatigue for male. But it was not suitable with walking on the shoes(middle heels) for female. And they will be very fatigue if they were in a long time walking or standing. As far as the slipperiness is concerned, it was shown that it was comparatively safe for the ordinary motions even though the surface was wet.