Modelling of Joint Molecular Weight-Branching Distributions and Branching Index in the High-Pressure Ethylene Polymerization in Tubular Reactors

DIETRICH, MAIRA L.; SARMORIA, CLAUDIA; BRANDOLIN, ADRIANA; ASTEASUAIN, MARIANO

Mar del Plata

Congreso; XVI Simposio Latinoamericano de Polímeros y XIV Simposio Iberoamericano de Polímeros; 2018

Comité Organizador SLAP 2018

The production of low-density polyethylene (LDPE) in high-pressure tubular reactors is a very important industrial process. The molecular properties of LDPE, such as the molecular weight distribution (MWD) and the short chain branching distribution (SCBD) and longchain branching distribution (LCBD) strongly influence the polymer processing and end-use properties. For this reason, several mathematical models of the polymerization reactor have been developed. However, very few of them calculate joint distributions of molecular weight and branches. These models are based on stochastic approaches, which are known to be very time-consuming. In the present work, for the first time a deterministic model of this process is developed that is able to predict the bivariate distributions MWD-LCBD and MWD-SCBD. The model also computes average molecular properties, conversion, temperature profiles and the branching index (g). The branching index is strongly related to therheological behavior of polymer melts.