Browsing by Author "Huh, M"

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    Effect of carbon nanotube functionalization on the structure and properties of poly(3-hydroxybutyrate)/MWCNTs biocomposites
    (Springer Link, 2014-07) Huh, M; Jung, MH; Park, YS; Kim, BJ; Kang, M; Holden, PJ; Yun, SI
    Multi walled carbon nanotubes (MWCNTs) covalently functionalized with an alkyl chain exhibited a better dispersion in poly(3-hydroxybutyrate) (PHB) solutions and cast films as compared with acid-treated MWCNTs (MWCNT-COOH) due to the much improved solubility in chloroform. The alkylated MWCNTs more effectively strengthened PHB composites than non-alkylated MWCNTs due to their uniform dispersion as well as stronger interaction of alkylated MWCNTs with the PHB matrix. Both acid-treated and alkylated MWCNTs added to PHB matrix facilitated crystallization kinetics. However the crystallization kinetics were found to be slower for the alkylated MWCNTs/PHB composites than acid-treated MWCNTs composites. The results may be ascribed to the inhibitory effect on PHB crystallization caused by the steric hindrance of the long alkyl chains attached to MWCNTs. © The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht 2014.
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    Fabrication of honeycomb-structured porous films from poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) via the breath figures method
    (Wiley, 2011-12-27) Huh, M; Jung, MH; Park, YS; Kang, TB; Nah, C; Russell, RA; Holden, PJ; Yun, SI
    Formation of porous films from poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) using the breath figures (BF) method was investigated by evaporating solutions in chloroform in humid air and examining film structure using optical and scanning electron microscopy (SEM). BF films were successfully fabricated from PHB (Mw = 486,000 g/mol) and displayed hexagonal arrays of pores, which varied in diameter (D = 7–2 μm) with solution concentrations (0.5–2.00%). SEM of fractured films also showed subsurface closed nano-pores (D = 500–700 nm). BF films cast from PHBV (5% HV) formed arrays with smaller pores and apparent surface defects. Differential scanning calorimetry showed that porous PHB and PHBV films produced using the BF method were more crystalline than nonporous solvent cast films of PHB and PHBV. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers