• Title/Summary/Keyword: Thermally conductive polymer

Search Result 25, Processing Time 0.018 seconds

Improvement of Thermal Conductivity of Poly(dimethyl siloxane) Composites Filled with Boron Nitride and Carbon Nanotubes (보론 나이트라이드와 탄소나노튜브로 충전된 실리콘 고무의 열전도도 향상)

  • Ha, Jin-Uk;Hong, Jinho;Kim, Minjae;Choi, Jin Kyu;Park, Dong Wha;Shim, Sang Eun
    • Polymer(Korea)
    • /
    • v.37 no.6
    • /
    • pp.722-729
    • /
    • 2013
  • In order to enhance the thermal conductivity of poly(dimethyl siloxane) (PDMS), boron nitride (BN) and carbon nanotubes (CNTs) were incorporated as the thermally conductive fillers. The amount of BN was increased from 0 to 100 phr (parts per hundred rubber) and the amount of CNTs was increased from 0 to 4 phr at a fixed amount of the boron nitride (100 phr). The thermal conductivity of the composites increased with an increasing concentration of BN, but the incorporation of CNTs had only a slight effect on the enhancement of thermal conductivity. Unexpectedly, the thermal degradation of the composites was accelerated by the addition of CNTs in 100 phr BN filled PDMS. Activation energy for thermal decomposition of the composites was calculated using the Horowitz-Metzger method. The curing behavior, electrical resistivity, and mechanical properties of PDMS filled with BN and CNTs were investigated.

A Low- Viscousity, Highly Thermally Conductive Epoxy Molding Compound (EMC)

  • Bae, Jong-Woo;Kim, Won-Ho;Hwang, Seung-Chul;Choe, Young-Sun;Lee, Sang-Hyun
    • Macromolecular Research
    • /
    • v.12 no.1
    • /
    • pp.78-84
    • /
    • 2004
  • Advanced epoxy molding compounds (EMCs) should be considered to alleviate the thermal stress problems caused by low thermal conductivity and high elastic modulus of an EMC and by the mismatch of the coefficient of thermal expansion (CTE) between an EMC and the Si-wafer. Though A1N has some advantages, such as high thermal conductivity and mechanical strength, an A1N-filled EMC could not be applied to commercial products because of its low fluidity and high modules. To solve this problem, we used 2-$\mu\textrm{m}$ fused silica, which has low porosity and spherical shape, as a small size filler in the binary mixture of fillers. When the composition of the silica in the binary filler system reached 0.3, the fluidity of EMC was improved more than twofold and the mechanical strength was improved 1.5 times, relative to the 23-$\mu\textrm{m}$ A1N-filled EMC. In addition, the values of the elastic modules and the dielectric constant were reduced to 90%, although the thermal conductivity of EMC was reduced from 4.3 to 2.5 W/m-K, when compared with the 23-$\mu\textrm{m}$ A1N-filled EMC. Thus, the A1N/silica (7/3)-filled EMC effectively meets the requirements of an advanced electronic packaging material for commercial products, such as high thermal conductivity (more than 2 W/m-K), high fluidity, low elastic modules, low dielectric constant, and low CTE.

Compositions for Photosensitive Polymer Resistor Paste Using Epoxy Acrylates (에폭시 아크릴레이트를 이용한 감광성 폴리머 저항 페이스트 조성)

  • Kim, Dong Kook;Park, Seong-Dae;Lee, Kyu-Bok;Kyoung, Jin-Bum
    • Applied Chemistry for Engineering
    • /
    • v.23 no.2
    • /
    • pp.157-163
    • /
    • 2012
  • Using six kinds of epoxy acrylates and a conductive carbon black, photosensitive resistor pastes were fabricated and then their developability in alkaline aqueous solution and the resistance values after thermal curing were evaluated. In order to impart the photocurability by UV exposure and the developability on alkaline solution, epoxy acrylate oligomers with carboxyl group, acrylate monomers, a photoinitiator and so forth were used. In addition, an organic peroxide was added into the paste to get a thermally curable composition. As a result, some of the pastes were not developed depending on the kinds of oligomers and, in the developed pastes, the measured resistance showed the different values depending on their compositions, even though they contain the same amount of carbon black. Finally, the optimum oligomer was selected and then, by adjusting the amount of carbon black, the kind of monomer and the curing temperature, the photosensitive resistor paste composition which showed the sheet resistance of about 0.5 $k{\Omega}/sq.$ could be obtained.

Crosslinked Composite Polymer Electrolyte Membranes Based On Diblock Copolymer and Phosphotungstic Acid (디블록 공중합체와 인텅스텐산을 이용한 가교형 복합 고분자 전해질막)

  • Kim, Jong-Hak;Koh, Joo-Hwan;Park, Jung-Tae;Seo, Jin-Ah;Kim, Jong-Hwa;Jho, Young-Choong
    • Membrane Journal
    • /
    • v.18 no.2
    • /
    • pp.116-123
    • /
    • 2008
  • Proton conductive hybrid nanocomposite polymer electrolyte membranes comprising polystyrene-5-poly (hydroxyethyl methacrylate) (PS-b-PHEMA), sulfosuccinic acid (SA) and phosphotungstic acid (PWA) were prepared by varying PWA concentrations. The PHEMA block was thermally crosslinked by SA via the esterification reaction between -OH of PHEMA and -COOH of SA. Upon the incorporation of PWA into the diblock copolymer, the symmetric stretching bands of the $SO_3^-$ group at $1187cm^{-1}$ shifted to a lower wavenumber at $1158cm^{-1}$, demonstrating that the PWA particles strongly interact with the sulfonic acid groups of SA. When the concentration of PWA was increased to 30wt%, the proton conductivity of the composite membrane at room temperature increased from 0.045 to 0.062 S/cm, presumably due to the intrinsic conductivity of the PWA particles and the enhanced acidity of the sulfonic acid in the membranes. The membrane containing 30wt% of PWA exhibited a proton conductivity of 0.126 S/cm at $100^{\circ}C$. Thermal stability of the composite membranes was also enhanced by introducing PWA nanoparticles.

Thermal Diffusivity of PEEK/SiC and PEEK/CF Composites (PEEK/SiC와 PEEK/CF 복합재료의 열확산도에 대한 연구)

  • Kim, Sung-Ryong;Yim, Seung-Won;Kim, Dae-Hoon;Lee, Sang-Hyup;Park, Joung-Man
    • Journal of Adhesion and Interface
    • /
    • v.9 no.3
    • /
    • pp.7-13
    • /
    • 2008
  • The particulate type silicon carbide (SiC) and fiber type carbon fiber (CF) filler, of similar thermal conductivities, were mixed with polyetheretherketone (PEEK) to investigate the filler effects on the thermal diffusivity. The SiC and CF fillers had a good and uniform dispersion in PEEK matrix. Thermal diffusivities of PEEK composites were measured from ambient temperature up to $200^{\circ}C$ by laser flash method. The diffusivities were decreased as increasing temperature due to the phonon scattering between PEEK-filler and filler-filler interfaces. Thermal diffusivity of PEEK composites was increased with increasing filler content and the thermal conductivities of two-phase system were compared to the experimental results and it gave ideas on the filler dispersion, orientation, aspect ratio, and filler-filler interactions. Nielson equation gave a good prediction to the experimental results of PEEK/SiC. The easy network formation by CF was found to be substantially more effective than SiC and it gave a higher thermal diffusivities of PEEK/CF than PEEK/SiC.

  • PDF