Article
  • A Study on the Rheological Properties of Branched Polycarbonates by Melt Polymerization
  • Choi SJ, Yoon KH, Kim HS, Yoo SY, Kim YC
  • 용융중합에 의한 분지형 폴리카보네이트의 유변학적 특성 연구
  • 최수정, 윤경화, 김희승, 유승윤, 김연철
Abstract
The branched polycarbonates (B-PCs) with two different branching agents were synthesized from melt polymerization. The contents of branching agent were in the range of 0.001∼0.005 mol%. The chemical structure of the synthesized PC was determined by FTIR, 1H NMR, and 13C NMR, spectroscopy. The molecular weight, glass transition and degradation temperatures were determined by GPC, DSC, and TGA. The molecular weight of the phloro type B-PC had a lower value than the other one, and the glass transition temperature increased with molecular weight. Compared with linear PC, the rheological properties of the B-PC indicated an increase of complex viscosity in the low frequency region and shear thinning tendency. Power law index(n) representing shear thinning was calculated by linear regression and the values were in the range of 0.483∼0.996. The rheological properties of the B-PCs were measured by a dynamic rheometer.

폴리카보네이트(polycarbonate, PC)에 화학적 구조가 다른 두 가지의 분지제를 첨가하여 용융중합으로 분지형 폴리카보네이트(branched PC, B-PC)를 합성하였다. 분지제의 함량은 0.001∼0.005 mol% 내에서 조절하였다. 합성된 PC의 화학구조는 FTIR, 1H NMR과 13C NMR 스펙트럼을 이용하여 확인하였으며, 분자량, 유리전이온도 및 분해온도는 GPC, DSC와 TGA를 이용하여 측정하였다. Phloro type의 분지제를 가지는 B-PC의 분자량이 낮은 값을 보여주었으며, 유리전이온도는 분자량에 따라 증가하였다. 두 형태의 B-PC 모두 선형 PC와 비교하였을 때 낮은 주파수(frequency) 영역에서 복합점도(complex viscosity)가 높게 나타났고, shear thinning 현상이 크게 나타났다. Shear thinning의 정도를 표시하는 power law index(n)는 선형회귀분석에 의해 계산되었고 0.483∼0.996 범위의 값을 보여주었다. Phloro 타입의 B-PC가 높은 shear thinning 경향을 보였으며 이들 B-PC의 유변학적 특성 은 동적유변측정기를 이용하여 측정하였다.

Keywords: melt polymerization; polycarbonate; branched; rheological properties.

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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

  • 2011; 35(4): 356-362

    Published online Jul 25, 2011

  • Received on Feb 11, 2011
  • Accepted on Mar 29, 2011