• Title/Summary/Keyword: Thermally conductive polymer

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A Review on Thermal Conductivity of Polymer Composites Using Carbon-Based Fillers : Carbon Nanotubes and Carbon Fibers

  • Hong, Jin-Ho;Park, Dong-Wha;Shim, Sang-Eun
    • Carbon letters
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    • v.11 no.4
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    • pp.347-356
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    • 2010
  • Recently, the use of thermal conductive polymeric composites is growing up, where the polymers filled with the thermally conductive fillers effectively dissipate heat generated from electronic components. Therefore, the management of heat is directly related to the lifetime of electronic devices. For the purpose of the improvement of thermal conductivity of composites, fillers with excellent thermally conductive behavior are commonly used. Thermally conductive particles filled polymer composites have advantages due to their easy processibility, low cost, and durability to the corrosion. Especially, carbon-based 1-dimensional nanomaterials such as carbon nanotube (CNT) and carbon nanofiber (CNF) have gained much attention for their excellent thermal conductivity, corrosion resistance and low thermal expansion coefficient than the metals. This paper aims to review the research trends in the improvement of thermal conductivity of the carbon-based materials filled polymer composites.

Preparation of Solventless UV Curable Thermally Conductive Pressure Sensitive Adhesives and Their Adhesion Performance

  • Baek, Seung-Suk;Park, Jinhwan;Jang, Su-Hee;Hong, Seheum;Hwang, Seok-Ho
    • Elastomers and Composites
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    • v.52 no.2
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    • pp.136-142
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    • 2017
  • Using various compositions of thermally conductive inorganic fillers with boron nitride (BN) and aluminum oxide ($Al_2O_3$), solventless UV-curable thermally conductive acrylic pressure sensitive adhesives (PSAs) were prepared. The base of the PSAs consists of 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate.The compositions of the thermally conductive inorganic fillers were 10, 15, 20, and 25 phr in case of BN, and 20:0, 15:5, 10:10, 5:15, and 0:20 phr in case of $BN/Al_2O_3$. The adhesion properties like peel strength, shear strength, and probe tack, and the thermal conductivity of the prepared PSAs were investigated with different thermally conductive inorganic filler contents. There were no significant changes in photo-polymerization behavior with increasing BN or $BN/Al_2O_3$ content. Meanwhile, the conversion rate and transmittance of the PSAs decreased and their thermal stabilities increased with increasing BN content. Their adhesion properties were also independent of the BN or $BN/Al_2O_3$ content. The dispersibility of BN in the acrylic PSAs was better than that of $Al_2O_3$ and it ranked the thermal conductivity in the following order: BN > $BN/Al_2O_3$ > $Al_2O_3$.

Trends in Development of Thermally Conductive Polymer Composites (열 전도성 고분자 복합재료의 개발 동향)

  • Hong, Jinho;Shim, Sang Eun
    • Applied Chemistry for Engineering
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    • v.21 no.2
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    • pp.115-128
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    • 2010
  • Recently the use heat sink material grows where the polymer filled with thermal conductive fillers effectively dissipates heat generated from electronic components. Therefore the management of heat is directly related to the lifetime of electronic devices. For the purpose of improving thermal conductivity of composites, fillers with excellent thermaly conductive behavior are commonly used. Polymer composites filled with thermally conductive particles have advantages due to their processibility, cheap price, and durability to the corrosion. This paper aims to review the thermal interface materials and their model equations for predicting the thermal conductivity of polymer composites, and to introduce the commercial thermal conductive fillers and their applications.

Effect of CaF2 Addition on the Crystallinity of Hexagonal Boron Nitride Nanoparticles (육방정 질화붕소 나노입자의 결정성에 미치는 불화칼슘 첨가의 영향)

  • Jung, Jae-Yong;Kim, Yang-Do;Kim, Young-Kuk
    • Korean Journal of Metals and Materials
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    • v.56 no.12
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    • pp.915-920
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    • 2018
  • With the development of modern microelectronics technologies, the power density of electronic devices is rapidly increasing, due to the miniaturization or integration of device elements which operate at high frequency, high power conditions. Resulting thermal problems are known to cause power leakage, device failure and deteriorated performance. To relieve heat accumulation at the interface between chips and heat sinks, thermal interface materials (TIMs) must provide efficient heat transport in the through-plane direction. We report on the enhanced thermal conduction of $Al_2O_3-based$ polymer composites, fabricated by the surface wetting and texturing of thermally conductive hexagonal boron nitride(h-BN) nanoplatelets with large anisotropy in morphology and physical properties. The thermally conductive polymer composites were prepared with hybrid fillers of $Al_2O_3$ macro beads and surface modified h-BN nanoplatelets. Hexagonal boron nitride (h-BN) has high thermal conductivity and is one of the most suitable materials for thermally conductive polymer composites, which protect electronic devices by efficient heat dissipation. In this study, we synthesized hexagonal boron nitride nanoparticles by the pyrolysis of cost effective precursors, boric acid and melamine. Through pyrolysis at $900^{\circ}C$ and subsequent annealing at $1500^{\circ}C$, hexagonal boron nitride nanoparticles with diameters of ca. 50nm were synthesized. We demonstrate that the addition of a small amount of calcium fluoride ($CaF_2$) during the preparation of the melamine borate adduct significantly enhanced the crystallinity of the h-BN and assisted the growth of nanoplatelets up to 100nm in diameters. The addition of a small amount of h-BN enhanced the thermal conductivity of the $Al_2O_3-based$ polymer composites, from 1.45W/mK to 2.33 W/mK.

Thermal Conductivity of Thermally Conductive Ceramic Composites and Silicon Carbide/Epoxy Composites through Wetting Process (세라믹 방열 복합체의 열전도도 분석 및 Wetting Process를 이용한 SiC/에폭시 복합체)

  • Hwang, Yongseon;Kim, Jooheon;Cho, WonChul
    • Polymer(Korea)
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    • v.38 no.6
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    • pp.782-786
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    • 2014
  • Various kinds of thermal conductive ceramic/polymer composites (aluminum nitride, aluminum oxide, boron nitride, and silicon carbide/epoxy) were prepared by a casting method and their optical images were observed by FE-SEM. Among these, SiC/epoxy composite shows inhomogeneous dispersion features of SiC and air voids in the epoxy matrix layer, resulting in undesirable thermal conductive properties. To enhance the thermal conductivities of SiC/epoxy composites, the epoxy wetting method which can directly infiltrate the epoxy droplet onto filtrated SiC cake was employed to fabricate the homogeneously dispersed SiC/epoxy composite for ideal thermal conductive behavior, with maximum thermal conductivity of 3.85W/mK at 70 wt% of SiC filler contents.

A study on the design and cooling of the heat sink with hybrid structure of conductive polymer composite and metal (열전도성 고분자 복합소재/금속 소재 하이브리드 구조의 방열기구 설계 및 방열특성에 관한 연구)

  • Yoo, Yeong-Eun;Kim, Duck Jong;Yoon, Jae Sung;Park, Si-Hwan
    • Design & Manufacturing
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    • v.10 no.3
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    • pp.14-19
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    • 2016
  • Thermally or electrically conductive filler reinforced polymer composites are extensively being developed as the demand for light weight material increases rapidly in industiral applications need good conductivity such as heat sink of the electronics or light. Carbon or ceramic materials like graphite, carbon nanotube or boron nitride are typical conductive fillers with good thermal or electical conductivity. Using these conductive fillers, the polymer composites in the market show wide range of thermal conductivity from approximately 1 W/mK to 20 W/mK, which is quite enhanced considering the thermal conductivity lower than 0.5 W/mK for most polymeric materials. The practical use of these composites, however, is yet limited to specific applications because most composites are still not conductive enough or too difficult to process, too brittle, too expensive for higher conductivity. For practical use of conductive composite, the thermal conductivity required depending on the heat releasing mode are studied first for simplified unit cooling geometry to propose thermal conductivities of the composites for reasonable cooling performance comparing with the metal heat sink as a reference. Also, as a practical design for heat sink based on polymer composite, composite and metal sheet hybrid structures are investigated for LED lamp heat sink and audio amplication module housing to find that this hybrid structure can be a good solution considering all of the cooling performance, manufacturing, mechanical performance, cost and weight.

Research Trends in Thermally Conductive Composites Filled with Carbon Materials (탄소재료가 내첨된 열전도성 복합재의 연구 동향)

  • An, Donghae;Kim, Kyung Hoon;Kim, Ji-Wook;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.73-83
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    • 2020
  • As electronic devices become more advanced and smaller, one of the biggest problems to solve is the heat affecting the efficiency and lifetime of instruments. High thermal conductivity materials, in particular, metal or ceramic ones, have been used to reduce the heat generated from devices. However, due to their low mechanical properties and high weight, thermally conductive composites composed with polymers having a light-weight and good mechanical properties as a matrix and carbon materials having high thermal conductivity as a thermally conductive filler have been attracting great attention. To improve the thermal conductivity of the composites, a phonon scattering must be suppressed to move phonon effectively. In this review, we classified researches related to phonon migration and scattering inhibition of carbon/polymer composites, and discussed various methods to improve thermal conductivity.

Thermal Conductivity and Adhesion Properties of Thermally Conductive Pressure-Sensitive Adhesives

  • Kim, Jin-Kon;Kim, Jong-Won;Kim, Myung-Im;Song, Min-Seok
    • Macromolecular Research
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    • v.14 no.5
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    • pp.517-523
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    • 2006
  • The effects of particle content, size and shape on the thermal conductivity (k) and adhesion properties of thermally conductive, pressure-sensitive adhesives (PSAs) were investigated. The matrix resins were thermally crosslinkable, 2-ethylhexyl acrylic polyol and ultraviolet (UV)-curable, random copolymer consisting of acrylic oligomer and various acrylates. We found that k increased with increasing diameter and particle aspect ratio, and was further enhanced due to the reduction of the interfacial thermal barrier when the coupling agent, which increases the adhesion between particles and the matrix resin, was used. On the other hand, adhesion properties such as peel strength and tack of the thermally crosslinkable resin decreased sharply with increasing particle content. However, for UV curable resin, increased particle addition inhibited the decrease in adhesion properties.

Synthesis of Hexagonal Boron Nitride Nanocrystals and Their Application to Thermally Conductive Composites (육방정 질화붕소 나노입자 합성 및 열전도성 복합체 응용)

  • Jung, Jae-Yong;Kim, Yang-Do;Shin, Pyung-Woo;Kim, Young-Kuk
    • Journal of Powder Materials
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    • v.23 no.6
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    • pp.414-419
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    • 2016
  • Much attention has been paid to thermally conductive materials for efficient heat dissipation of electronic devices to maintain their functionality and to support lifetime span. Hexagonal boron nitride (h-BN), which has a high thermal conductivity, is one of the most suitable materials for thermally conductive composites. In this study, we synthesize h-BN nanocrystals by pyrolysis of cost-effective precursors, boric acid, and melamine. Through pyrolysis at $900^{\circ}C$ and subsequent annealing at $1500^{\circ}C$, h-BN nanoparticles with diameters of ~80 nm are synthesized. We demonstrate that the addition of small amounts of Eu-containing salts during the preparation of melamine borate precursors significantly enhanced the crystallinity of h-BN. In particular, addition of Eu assists the growth of h-BN nanoplatelets with diameters up to ~200 nm. Polymer composites containing both spherical $Al_2O_3$ (70 vol%) and Eu-doped h-BN nanoparticles (4 vol%) show an enhanced thermal conductivity (${\lambda}{\sim}1.72W/mK$), which is larger than the thermal conductivity of polymer composites containing spherical $Al_2O_3$ (70 vol%) as the sole fillers (${\lambda}{\sim}1.48W/mK$).