In this paper the high‐temperature thermal field flow fractionation method is exploited for the analysis of polyethylene (PE). The experimental apparatus set‐up, obtained by simply modifying a commercial instrument, is presented. The numerical procedure for deriving retention calibration plot versus molecular weight is discussed with reference to the specific polymer‐solvent pair, PE‐o‐dichlorobenzene (ODCB), here employed. Different methods for computing the physicochemical data set of the solvent, necessary for calibration, are compared. The selectivity of the checked PE‐ODCB system proves comparable with respect to the values currently found in thermal field‐flow fractionation (ThFFF) analysis. Differences are found between PE and polystyrene (PS) analysis in the same solvent. The conditions for high temperature ThFFF operation in PE analysis and their advantages are discussed with respect to the standard SEC technique for PE, PS, and PE‐PS copolymer analysis. Molecular weight distributions obtained by ThFFF of two PE commercial samples agree with those obtained by SEC. © 1995 John Wiley & Sons, Inc. Copyright © 1995 John Wiley & Sons, Inc.
High temperature thermal field‐flow fractionation of polyethylene and polystyrene
PASTI, Luisa;DONDI, Francesco;
1995
Abstract
In this paper the high‐temperature thermal field flow fractionation method is exploited for the analysis of polyethylene (PE). The experimental apparatus set‐up, obtained by simply modifying a commercial instrument, is presented. The numerical procedure for deriving retention calibration plot versus molecular weight is discussed with reference to the specific polymer‐solvent pair, PE‐o‐dichlorobenzene (ODCB), here employed. Different methods for computing the physicochemical data set of the solvent, necessary for calibration, are compared. The selectivity of the checked PE‐ODCB system proves comparable with respect to the values currently found in thermal field‐flow fractionation (ThFFF) analysis. Differences are found between PE and polystyrene (PS) analysis in the same solvent. The conditions for high temperature ThFFF operation in PE analysis and their advantages are discussed with respect to the standard SEC technique for PE, PS, and PE‐PS copolymer analysis. Molecular weight distributions obtained by ThFFF of two PE commercial samples agree with those obtained by SEC. © 1995 John Wiley & Sons, Inc. Copyright © 1995 John Wiley & Sons, Inc.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
