Regarding the complexity of Ziegler-Natta catalyst kinetics in polypropylene polymerization, so far, there is no adequate model to determine the best process conditions for predicting average molecular weight and dispersity as the most crucial final product properties index. Consequently, a validated model has been developed which describes the relationship between the kinetic model and the existing gap using the polymer moment balance approach. It was concluded that increasing reaction temperature and hydrogen amount are useful and improve the final product indices to a certain limit, but afterwards they have harmful effects on the indices.

In this study, the effect of reaction temperature and hydrogen amount, as the most effective process variables on the Ziegler-Natta catalysts yield during propylene polymerization, was investigated with the aid of a validated mathematical model. The approach applied in this modelling was the <i>polymer moment balance technique</i> (<i>population balance approach</i>) derived from the statistics expected value. The model was coded in MATLAB<sup>®</sup> & Simulink<sup>®</sup>, and then validated by experimental data coming from a laboratory-scale reactor. The main target of this study was to gain considerable insight into Ziegler-Natta catalyst performance against variables change. The model might be applicable for catalyst makers to evaluate and improve their catalysts, and could also be useful for process chemical engineers to easily operate the plant, replace new catalyst, optimise process conditions, generate new formulation for a new grade, and use maximum catalytic potential. Accordingly, the model could be applied in basic and applied research in this field.

Communications of the primary particle diameter determined with LII and the CTAB number ± the specific surface without consideration of micropores ± is observable. The error bars result from the standard deviations of the average values. It should be noted that the size of the standard deviation is determined by fluctuations of the particle size, i.e. among other things by reactor fluctuations, and is not a characteristic of the measuring technique as already shown beyond doubt in laboratory tests at stationary objects. ConclusionsThe investigations proved the applicability of the laserinduced incandescence technique for the on-line characterization of carbon blacks, which holds for both the application of the measuring technique in an industrial environment in principle and the successful in-situ measurement of primary particle sizes. In particular the investigations with fine parameter variations clearly show that LII represents a very good tool for direct process control without time delay. Changes in the primary particle size and/or disturbances during the process can be detected with LII practically immediately. A correlation between the primary particle size d P measured by means of LII and the CTAB number could be found. A connection between the iodine number and LII results is not clearly given, i.e., differences in the porosity which determines the iodine number among other things, without changes in particle size (characterized by the CTAB number) are not determined with LII. These results seriously underline the thesis that with LII a measure for the enveloping specific surface area is determined. Little experimental effort makes the employment of a LII sensor particularly interesting for process control. Apart from the quantitative determination of the primary particle size the measuring technique is very helpful also to decide whether an operating condition of the reactor has already stabilized and/or behaves stationarily. Small fluctuations, in particular of periodic kind, can be detected very well by the possibility of a continuous measurement where values are taken with a frequency of up to 20 Hz. Communications which include: Interval I is finished when all micelles have disappeared, the rate of monomer addition depends only on the nature of the terminal group. During the polymerization period no variation is considered for the reaction constants. A bimodal molecular weight distribution was obtained, which is evidence of tri-functional branching and tetra-functional crosslinking. The results show an increase in the degree of conversion, which leads to a shift in the molecular weight distribution toward higher values. An increase in the emulsifier concentration increases the surface area under the second peak in the molecular weight distribution. The MC simulation as a statistical approach, gave results that are in agreement with the Smith-Ewart theory for insoluble monomers in continuous media.

Co-catalyst has several roles in propylene polymerization such as site activation, chain transfer, site transformation and Poisson deactivation (or Poisson scavenger). These functionalities strongly impact the most important of the final product properties indices namely the number and weight average. Molecular weight, polydispersity index, melt flow index and even the yield of Ziegler-Natta catalyst. Therefore, the Co-catalyst role as an independent process variable should be carefully investigated in the polymerization. In this study, investigating the co-catalyst effects on the final properties indices and the yield of the catalyst as the existing gap was defined as the aims of this study. We attempt to reply to the problems in a proper way in the absence of hydrogen and at the optimal temperature reaction by proposing a newly developed mathematical model. This model was programmed in MATLAB & Simulink software, then was validated by using experimental data. Through the model, the optimal amount of the used co-catalyst could be determined conveniently.

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