Hyo-Seong Jin

Publications (2)2.44 Total impact

• Source

  Available from: korea.ac.kr

  Article: Synthesis and characterization of colorless polyimide nanocomposite films containing pendant trifluoromethyl groups

  Hyo-Seong Jin, Jin-Hae Chang
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  ABSTRACT: A series of colorless polyimide (PI) nanocomposite films were synthesized from 2,2'-bis(3,4-dicarbox-yphenyl)hexafluoropropane dianhydride (6FDA) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) with various organoclay contents by solution intercalation polymerization to poly(amic acid)s, followed by thermal imi-dization. The variation with the organoclay content of the thermomechanical properties, morphology, and optical transparency of the hybrids was examined at organoclay loadings ranging from 0 to 1.0 wt%. The hybrid films showed high optical transparency and almost no color, with cut-off wavelengths ranging from 352 and 356 nm and very low b* values of 1.19-1.77. The hybrid PI films showed good thermal properties with a glass transition tem-perature of 280-287 o C. Most films did not show any significant thermal decomposition below 490 o C. The addition of only a small amount of organoclay was sufficient to improve the tensile properties of the PI films with maximum enhancement being observed at 0.25 wt% organoclay. Moreover, these PI hybrids also had low coefficients of ther-mal expansion (CTE).
  Macromolecular Research 01/2008; 16:503-509. · 1.15 Impact Factor
• Article: Colorless polyimide nanocomposite films: Thermomechanical properties, morphology, and optical transparency

  Hyo‐Seong Jin, Jin-Hae Chang
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  ABSTRACT: Polyimide (PI)/organoclay hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium-mica (C12PPh-Mica) as the organoclay. The variations with organoclay content of the thermomechanical properties, morphology, and optical transparency of the hybrids were examined for concentrations from 0 to 1.0 wt %. For low clay contents (≤ 0.5 wt %), the clay particles are better dispersed in the matrix polymer, without the formation of large agglomerates of particles, than they are for high clay contents. However, agglomerated structures form and become denser in the PI matrix for clay contents ≥ 0.75 wt %. This is in agreement with the observed trends in the thermomechanical properties and the optical transparency, which worsen drastically when the clay content of the C12PPh-Mica/PI hybrids reaches 0.75 wt %. However, when the amount of organoclay in the hybrid is 0.75 wt %, the initial modulus of the hybrid film is at its maximum value. The PI hybrid films were found to exhibit excellent optical transparencies and to be almost colorless. It was found, however, that the transparency decreases slightly with increases in the organoclay content because of agglomeration of the clay particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
  Journal of Applied Polymer Science 09/2007; 107(1):109 - 117. · 1.29 Impact Factor