Linear Viscoelasticity of Polystyrene Solution Having a Wide Molar Mass Distribution around the Coil Overlap Concentration (故 升田利史郎先生追悼号) Linear Viscoelasticity of Polystyrene Solution Having a Wide Molar Mass Distribution around the Coil Overlap Concentration

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Abstract

Linear viscoelastic behavior for solutions of polystyrene (PS) having broad molar mass distribution (MMD) in tricresyl phosphate (TCP), which is a good solvent, was investigated at concentrations, <i>c</i>, around the coil-overlapping-concentration, <i>c</i><sup><font size="-1">*</font></sup>. GPC measurement indicated that molar mass distribution of sample was close to most probable distribution. Below <i>c</i><sup><font size="-1">*</font></sup>, the viscoelastic behavior was described well with the Rouse-Zimm (RZ) theory if considered molar mass distribution. On the other hand, at concentrations around the <i>c</i><sup><font size="-1">*</font></sup>, the viscoelastic behavior was not described by the RZ mode alone and the additional long-time (LT) modes were needed, similarly to the case of monodispersed molar mass distribution system. This implies that the LT modes are originated by the inter-molecular interaction. Compared with the monodispersed system, magnitude of the LT modes showed the same <i>c</i> dependence, being proportional to <i>c</i><sup><font size="-1">2</font></sup> while the relaxation time of the LT mode showed a different <i>c</i> dependence. Owing to the broad MMD and the LT term, the viscoelastic spectra have the broad terminal flow relaxation time distribution but still can be apparently fit with the Rouse-Zimm (RZ) theory, resulting that the apparent molar mass, <i>M</i><sub><font size="-1">w</font></sub><sup><font size="-1">app</font></sup>, is higher molar mass than the real molar mass depending at concentrations of <i>c</i> > <i>c</i><sup><font size="-1">*</font></sup>. At <i>c</i> / <i>c</i><sup><font size="-1">*</font></sup> = 2.9, <i>M</i><sub><font size="-1">w</font></sub><sup><font size="-1">app</font></sup> was estimated at 4.1 times larger than the true molar mass. By considering the LT terms, the molar mass can be estimated by fitting with the Rouse-Zimm (RZ) term.

Journal

  • Nihon Reoroji Gakkaishi

    Nihon Reoroji Gakkaishi 41(3), 151-156, 2013

    The Society of Rheology, Japan

Codes

  • NII Article ID (NAID)
    130004926492
  • NII NACSIS-CAT ID (NCID)
    AN00198812
  • Text Lang
    ENG
  • ISSN
    0387-1533
  • NDL Article ID
    024766674
  • NDL Call No.
    Z14-725
  • Data Source
    NDL  J-STAGE 
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