In this paper different techniques for the deconvolution of experimental gel permeation chromatography (GPC) curves of polymers obtained from batch reactors are examined with the aim of improving the modelling of the polymerization process. The deconvolution of the GPC curves gives insight into the effects of diffusive phenomena on the values of the average molecular weights (M̄n and M̄w) and the molecular weight distribution (MWD) of the polymer. Two methods, one based on a two-peak deconvolution and the other one based on a multi-peak deconvolution, are compared. The different characteristics and relative merits of the two methods are illustrated using several sets of experimental data. In conclusion, the first method is less accurate but allows a separation of the two contributions given by the chemical and diffusive control of the MWD; the second method has a sound theoretical background (confirms the prediction of the free volume theory) and is potentially much superior but the results prove to be more sensitive to the quality of the experimental part
Analysis of Molecular Weight Distribution in Free Radical Polymerization: Modeling of MWD from the Analysis of Experimental GPC Curves
SCALI, CLAUDIO
1999-01-01
Abstract
In this paper different techniques for the deconvolution of experimental gel permeation chromatography (GPC) curves of polymers obtained from batch reactors are examined with the aim of improving the modelling of the polymerization process. The deconvolution of the GPC curves gives insight into the effects of diffusive phenomena on the values of the average molecular weights (M̄n and M̄w) and the molecular weight distribution (MWD) of the polymer. Two methods, one based on a two-peak deconvolution and the other one based on a multi-peak deconvolution, are compared. The different characteristics and relative merits of the two methods are illustrated using several sets of experimental data. In conclusion, the first method is less accurate but allows a separation of the two contributions given by the chemical and diffusive control of the MWD; the second method has a sound theoretical background (confirms the prediction of the free volume theory) and is potentially much superior but the results prove to be more sensitive to the quality of the experimental partI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
