Documents disponibles écrits par cet auteur

Enhancement of gas selectivities of hexafluoroisopropylidene-based polyimides with poly(methylmethacrylate) blending / Hyungu Im in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8663–8669 Titre : Enhancement of gas selectivities of hexafluoroisopropylidene-based polyimides with poly(methylmethacrylate) blending Type de document : texte imprimé Auteurs : Hyungu Im, Auteur ; Hyomi Kim, Auteur ; Chang Keun Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 8663–8669 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Poor  gas  selectivity  Polyimides  Hexafluoroisopropylidene  diphthalic  anhydride  Hexafluoroisopropylidene  diamine  Diaminobenzoic  acid Résumé : To enhance poor gas selectivity of polyimides based on hexafluoroisopropylidene diphthalic anhydride (6FDA), such as 6FDA−4,4′-hexafluoroisopropylidene diamine (6FDA−6FpDA) and 6FDA−6FpDA:diaminobenzoic acid (6FDA−6FpDA:DABA), membranes were fabricated from their blends with poly(methylmethacrylate) (PMMA). The resulting polyimides formed homogeneous mixtures with PMMA, regardless of the blend compositions. The miscible blends underwent phase separation upon heating due to the lower critical solution temperature phase behavior. The phase separation temperature of the 6FDA−6FpDA/PMMA blend was greater than that of the 6FDA−6FpDA:DABA/PMMA when the composition was fixed. Adding a small amount of PMMA dramatically increased the gas selectivity of the membrane. In addition, the gas selectivity of most blends was better than that of pure PMMA. The membranes showed performance advantages for the trade-off trend between gas permeability coefficient and selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900643p [article] Enhancement of gas selectivities of hexafluoroisopropylidene-based polyimides with poly(methylmethacrylate) blending [texte imprimé] / Hyungu Im, Auteur ; Hyomi Kim, Auteur ; Chang Keun Kim, Auteur . - 2010 . - pp. 8663–8669. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8663–8669 Mots-clés : Poor  gas  selectivity  Polyimides  Hexafluoroisopropylidene  diphthalic  anhydride  Hexafluoroisopropylidene  diamine  Diaminobenzoic  acid Résumé : To enhance poor gas selectivity of polyimides based on hexafluoroisopropylidene diphthalic anhydride (6FDA), such as 6FDA−4,4′-hexafluoroisopropylidene diamine (6FDA−6FpDA) and 6FDA−6FpDA:diaminobenzoic acid (6FDA−6FpDA:DABA), membranes were fabricated from their blends with poly(methylmethacrylate) (PMMA). The resulting polyimides formed homogeneous mixtures with PMMA, regardless of the blend compositions. The miscible blends underwent phase separation upon heating due to the lower critical solution temperature phase behavior. The phase separation temperature of the 6FDA−6FpDA/PMMA blend was greater than that of the 6FDA−6FpDA:DABA/PMMA when the composition was fixed. Adding a small amount of PMMA dramatically increased the gas selectivity of the membrane. In addition, the gas selectivity of most blends was better than that of pure PMMA. The membranes showed performance advantages for the trade-off trend between gas permeability coefficient and selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900643p

Fabrication of novel polyurethane elastomer composites containing hollow glass microspheres and their underwater applications / Hyungu Im in Industrial & engineering chemistry research, Vol. 50 N° 12 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 12 (Juin 2011) . - pp. 7305-7312 Titre : Fabrication of novel polyurethane elastomer composites containing hollow glass microspheres and their underwater applications Type de document : texte imprimé Auteurs : Hyungu Im, Auteur ; Sang Chul Roh, Auteur ; Chang Keun Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 7305-7312 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microsphere  Hollow  glass  Composite  material Résumé : Thermoplastic polyurethane (TPU) elastomers are frequently used in underwater applications. Desirable polymeric materials have lower densities and lower swelling ratios for seawater and paraffin oil, along with better mechanical strength than TPU after impregnation. To fabricate desirable composites for underwater applications, hollow glass microspheres (HGMs), TPU prepared from poly(tetramethylene glycol) (PTMG), and methyl diphenyl diisocyanate (MDI) were used. TPU-grafted hollow glass microspheres (TPU-g-HGM) were prepared to fabricate a composite that has better interfacial adhesion between the TPU matrix and the HGMs. The tensile strength of the composite increased with increasing HGM content, whereas the swelling ratio and density of the composite decreased with increasing HGM content. At fixed HGM content in the composite, the TPU/TPU-g-HGM composite exhibited a lower swelling ratio and better tensile strength than the TPU/HGM composite. In addition, the TPU/TPU-g-HGM composite exhibited enhanced mechanical strength as compared to TPU after being impregnated with seawater and paraffin oil. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24239044 [article] Fabrication of novel polyurethane elastomer composites containing hollow glass microspheres and their underwater applications [texte imprimé] / Hyungu Im, Auteur ; Sang Chul Roh, Auteur ; Chang Keun Kim, Auteur . - 2011 . - pp. 7305-7312. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 12 (Juin 2011) . - pp. 7305-7312 Mots-clés : Microsphere  Hollow  glass  Composite  material Résumé : Thermoplastic polyurethane (TPU) elastomers are frequently used in underwater applications. Desirable polymeric materials have lower densities and lower swelling ratios for seawater and paraffin oil, along with better mechanical strength than TPU after impregnation. To fabricate desirable composites for underwater applications, hollow glass microspheres (HGMs), TPU prepared from poly(tetramethylene glycol) (PTMG), and methyl diphenyl diisocyanate (MDI) were used. TPU-grafted hollow glass microspheres (TPU-g-HGM) were prepared to fabricate a composite that has better interfacial adhesion between the TPU matrix and the HGMs. The tensile strength of the composite increased with increasing HGM content, whereas the swelling ratio and density of the composite decreased with increasing HGM content. At fixed HGM content in the composite, the TPU/TPU-g-HGM composite exhibited a lower swelling ratio and better tensile strength than the TPU/HGM composite. In addition, the TPU/TPU-g-HGM composite exhibited enhanced mechanical strength as compared to TPU after being impregnated with seawater and paraffin oil. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24239044