Influence of Polymerization Parameters

Little data is available concerning the effect polymerization parameters such as monomer concentration, type and concentration of aluminum alkyl, hydrogen, and temperature have on Cp and kp values. The polymerization rate is generally considered proportional to the monomer concentration 32,38, The widest range of pro- 

However, this has been demonstrated experimentally only within rather narrow monomer concentration intervals. Kashiwa 38), for example, found that Cp and kp values were practically constant at propylene concentrations comprised between 0.2 and 0.7 mol/1 at 10 °C (see Table 9). According to Zakharov126) the Cp and kp values for the TiCl4/MgCl2(P)—AlEt3 catalyst system do not appreciably vary at 80 °C for ethylene concentrations ranging from 0.15 to 0.6 mol/1 The influence of the aluminum alkyl concentration has recently been studied by Kashiwa 38) in short time polymerization of propylene at 10 °C, with a catalyst system consisting of 

The availability of such data would be very useful for a direct experimental verification of those reaction models which provide for competitive adsorption of the monomer, the aluminum alkyl and the hydrogen on the catalyst surface86 87. The studies carried out to-date on the effect of temperature do not even permit to establish clearly, whether the decline in catalytic activity, observed in propylene polymerization above 60-70 °C with TiCl4. EB/MgCl2—AlEt3 type catalysts 45,69,98), is due to an irreversible deactivation of active centers or to some other phenomena. 

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This review covering the influence of polymerization parameters on MWD clearly shows how impossible it is to elaborate laws valid for all catalytic systems. Furthermore, numerous discrepancies among the experimental data prevent any attempt at their rationalization based on a general kinetic model, even for similar catalytic systems. However, at least qualitatively, the following conclusions can be reasonsably drawn ... 

Desilvestro J, Scheifele W (1993) Morphology of electrochemicaUy prepared polyaniline. Influence of polymerization parameters. J Mater Chem 3(3) 263-272... 

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