Monomer activity measurement ideality

The nature of the active species in the anionic polymerization of non-polar monomers, e. g. styrene, has been disclosed to a high degree. The kinetic measurements showed, that the polymerization proceeds in an ideal way, without side-reactions, and that the active species exist in the form of free ions, solvent-sparated and contact ion pairs, which are in a dynamic equilibrium (l -4). For these three species the rate constants and activation parameters (including the activation volumes), as well as the rate constants and equilibrium constants of interconversion have been determined (4-7.) Moreover, it could be shown by many different methods (e. g. conductivity and spectroscopic methods) that the concept of solvent-separated ion pairs can be applied to many ionic compounds in non-aqueous polar solvents (8). 

In the case of lumped processes, hybrid model design focuses on reducing a complex set of static relationships with mat r fit parameters by overall fiizzy sub-models. These sub-models can be derived from measurements. A polymer reactor has been used as an example. In the liquid phase reactor, which is ideally stirred, monomer reacts to polymer by means of a single site metallocene catalyst. The inputs of the reactor are listed in Table 30.2 the load Fin, the hydrogen fraction of the feed xh2, the activated catalyst fraction Xc,a, the non-activated catalyst fraction Xc,na, the monomer fraction and the jacket temperature 7 adfe,. The most important outputs are the molecular weight distribution MWD (or q, the chain termination probability which is inversely proportional to MWD) and the conversion or (feed mass fraction conversion). The model is described in detail by Roffel and Betlem (2003). The requirements for the model of this reactor are ... 

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