Article
  • Viscosity Behavior of Dilute Solutions of PET in Mixed Solvents : 1. Solvent(1)-Solvent(2)-Polymer(3) Ternary System
  • Park TK, Lee JO
  • 혼합용매계에서 묽은 PET 용액의 점도거동: 1. 용매(1)-용매(2)-고분자(3)3성분계
  • 박태경, 이장우
Abstract
The dilute solution behavior(mainly the intrinsic viscosity, [η] of a polymer in a solvent mixture has been investigated for ternary system of hexafluoroisopropanol(1)- trifluoroacetic acid(2)-PET(3) (HFIP/TFA/PET) in terms of the composition of the mixed solvent, temperature(T), and molecular weight(MW) of PET. Four PET samples of different MW's used for the analysis have been synthesized by the direct esterification method, and intrinsic viscosities(IV's) have been obtained by means of "one point method" at low concentration. The present mixed solvent system exhibited the "synergistic effect" in the composition dependence of the Ⅳ, i. e. [η]>[η]av (where [η]av is the weight average of the [η] values for the pure liquids). From Flory's thermodynamic point of view, the system showed the viscosity behavior belonging to the χ23-χ13 <χ12 case with the maximum solvent power at the composition of HFIP/TFA (60 : 40 vol. %). In addition, the IV had the tendency to decrease with increasing T over nearly entire composition range of the mixed solvent. From the analysis of composition dependence of IV, the present system is considered to deviate a little from the "single liquid approximation".

Hexafluoroisopropanol(HFIP) (1)-trifluoroacetic acid(TEA) (2)-PET(3) (HFIP/TFA/PET)의 3성분계를 대상으로 묽은 용액에서의 점도 거동을 혼합용매의 조성, 온도, 분자량등에 따라 조사하였다. 직접 에스테르화 방법에 의해 분자량이 다르게 합성된 4종의 PET시료에 대하여 "one point method"에 의하여 고유점도를 측정하였다. 이 계에서는 혼합용매의 조성에 따라 고유점도의 "synergistic effect"가 관측되었고, Flory 상호작용 파라미터간에 χ23-χ13 <χ12의 관계가 성립하는 혼합용 매계에 속하는 점도 거동을 나타내었으며, 그리고 HFIP/TFA(60 : 40 vol. %)의 조성에서 최대의 용해능(solvent power)을 보였다. 아울러 혼합용매의 전 조성영역에서 온도가 상승함에 따라 고유점도가 저하하는 경향을 나타내었고 혼합용매의 조성변화에 따른 점도거동의 조사를 통하여 본 계는 "단일용매근사(single liquid approximation)"로부터 다소간 벗어나고 있음을 알 수 있었다.

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2023 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 1991; 15(3): 311-318

    Published online Jun 25, 1991