Analysis of the molecular weight distribution in polymerization process

In this paper different techniques for the deconvolution of experimental GPC curves obtained from batch reactors are examined with the aim of improving the modelling of the polymerization process. The deconvolution of the experimental GPC curves gives insight into the effects of diffusive phenomena on the values of the average molecular weights (Mn and Mw) and the Molecular Weight Distribution (MWD) of the polymer product. Two methods, one based on a two-peak deconvolution and the other 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. As conclusions, the first method is less accurate but allows a separation of the two contributions given by the chemical and diffusive control to the MWD; the second method has a sound theoretical background (confirms the prediction of the free volume theory) and is potentially much superior but results show it to be more sensitive to the quality of the experimental data.