화학공학소재연구정보센터
Polymer(Korea), Vol.14, No.2, 130-137, April, 1990
Gel Permeation Chromatography에 의한 범용 Poly(Vinyl Chloride)의 특성 결정
Characterization of Commercial Poly(Vinyl Chloride) by Gel Permeation Chromatography
초록
한 낮은 농도의 점도 data를 이용하여 고유점도를 결정하는, Solomon 등이 제안한, "single-point"법의 적용가능성이 25℃, PVC-THF계에서 종래의 외삽법에 의한 값들과 비교 시험되었다. GPC로 3종의 다른 PVC 시료들의 정화한 분자량과 분자량 분포를 구하기 위하여 "hydrodynamic volume average molecular weight 개념"에 근거한 Mahabadi의 방법에 따라 단지 고유점도와 GPC data만으로 25℃, PVC-THF 계의 Mark-Houwink 상수를 평가 하였는데 얻어진 값은 K=1.16×10-3dl/gr이고 a=0.60이었다. 이들 K, a값을 이용하여 수평균(Mn), 중량평균(Mw) 분자량 및 이들의 비(Mw/Mn)인 분자량 분포 (MWD)를 계산하였고, 고유점도의 실험치와 Mark-Houwink 상수를 이용하여 계산한 값의 비교를 통해 Mahabadi 이론의 타당성도 함께 조사되었다 또한 "universal calibration법"에 의해 분자량과 분자량 분포를 평가할때 범하기 쉬운 오류도 지적하였다.
The applicability of "single-point" methods as represented by Solomon''sequation for determining intrinsic viscosity using viscosity data at one low concentration has been tested to the PVC-THF system at 25℃, in comparison with the values obtained by conventional extrapolation methods. In order to determine correct MW''s and MWD''s of three different PVC samples by GPC, Mark-Houwink constants of the PVC - THF system at 25℃ have been evaluated following Mahabadi''s procedure, based on the "hydrodynamic volume-average molecular weight concept", using only intrinsic viscosity(Ⅳ) and GPC data, yielding K=1.16×10-3 dl/gr and a=0.60. The number(Mn) and weight(Mw) average MW''s, and hence MWD expressed in terms of Mw/Mn, have been calculated using these K and a values, together with the validity test of Mahabadi''s theory through comparison of calculated and experimental values of intrinsic viscosity. In addition, a fallacy liable to occur in the evaluation of MW and MWD by "universal calibration technique" was pointed out to prevent erroneous results.
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