Abstract An extended mathematical model of an autoclave reactor for the high pressure polymerization of ethylene is presented. It allows one to predict not only the conversion but also the molar mass distribution, short and long chain branching, number and weight average degree of polymerization as a function of the synthesis conditions. The model includes the initiation step, chain growth, chain termination by disproportionation and combination, chain transfer to the monomer, polymer and modifier, and intramolecular chain transfer in the polymer radical. Number and weight average degrees of polymerization were computed by means of generating functions. For the calculation of the molar mass distribution recursion formulae are given. The performance of the model is shown by the good agreement of the predicted values with the experimental data.
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