• Title/Summary/Keyword: bio materials

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Performance Evaluation of Bio-Composites Composed of Acetylated Kenaf Fibers and Poly(lactic acid) (PLA) (아세틸화 케나프 섬유와 폴리락트산으로 구성된 바이오복합재료의 물성 평가)

  • Chung, T.J.;Lee, B.H.;Lee, H.J.;Kwon, H.J.;Jang, W.B.;Kim, H.J.;Eom, Y.G.
    • Elastomers and Composites
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    • v.46 no.3
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    • pp.195-203
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    • 2011
  • Eco-friendly materials or bio-composites were made with poly(lactic acid) (PLA) as matrix polymer and kenaf fibers as filler. Also, acetylated kenaf fibers and compatibilizer were adopted in order to improve the interfacial adhesion between fiber and polymer. In this study, the effect of chemical modification and compatibilizer on the mechanical-viscoelastic and morphology properties of the bio-composites was discussed. The hydrophobic fibers by acetylation were known to show better interfacial bonding with the matrix polymer and resulted in improved performance and morphology. Viscoelastic property and glass transition temperature, however, were not nearly enhanced.

Effects of Oxidation on the Order-disorder Transition in NiPt Alloy Nano Crystals

  • Seo, Ok-Gyun;Hwang, Jae-Seong;Song, Da-Hyeon;Lee, Ji-Yeon;Choe, Jeong-Won;Lee, Su-Ung;Gang, Hyeon-Cheol;No, Do-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.253-253
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    • 2012
  • The effects of oxidation on the order-disorder transition in NiPt bimetallic alloy crystal have been investigated using in-situ synchrotron x-ray scattering technique. The temperature dependence of the crystal structure and the order parameter were measured during in-situ heating and cooling under vacuum and oxygen environments. The order-disorder transition temperature of NiPt alloy crystals in vacuum was between $615^{\circ}C$ and $627^{\circ}C$. On the other hand under oxygen environment, the transition temperature decreases by about $31^{\circ}C$ after the oxidation. The change of the transition temperature can be explained by the formation of NiO crust on the surface of NiPt crystal, which alters the composition of the Ni and Pt atoms. Since the transition temperature depends sensitively on the Ni-Pt composition, the transition temperature changes as Ni atoms diffuse out to form NiO.

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Thermal behavior of Flame Retardant Filled PLA-WF Bio-Composites

  • Choi, Seung-Woo;Lee, Byoung-Ho;Kim, Hyun-Joong;Kim, Hee-Soo
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.2
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    • pp.155-163
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    • 2009
  • This study examined the thermal stability of PLA-WF bio-composites. Wood flour (WF)-filled PLA bio-composites were reinforced with the flame retardants, Melamine pyrophosphate (MPP), resorcinol bis (diphenyl phosphate) (RDP) and zinc borate (ZB). The flame retardant was compounded with PLA and natural biodegradable filler. The thermal properties of the biodegradable polymer and bio-composites reinforced with the flame retardant were measured and analyzed by DSC, DMA and TGA. The results showed that the flame retardant-reinforced biodegradable bio-composite exhibited improved thermal properties.