Macromol. React. Eng. 6/2020

Abstract

Front Cover: Polymer reaction engineering offers the theoretical background for the modeling pathway from polymerization process conditions to polymer microstructure and end‐use properties. This pathway consists of concrete steps: (i) connection of reaction conditions to polymer microstructure, (ii) connection of microstructure to first level properties, and, (iii) estimation of second level properties as a function of microstructure and/or first level properties. This is reported by Vasileios Touloupidis, Gerold Rittenschober, and Christian Paulik in article 2000028.

Single Particle Growth, Fragmentation and Morphology Modelling: A DEM Approach

“…The catalyst reactivity (in this case, described by its propagation parameter) [ 3 ] guides the particle growth rate. Nevertheless, monomer diffusion potential (via open pores and polymer) will further define the available local amount of monomer that reaches the active site.…”

Multiscale modelling of multizone gas phase propylene (co)polymerization reactors—A comprehensive review

“…In general, the ZN catalysts are multi‐sites, which leads to the production of polyolefins with broad MWD. Typically, these catalysts are said to contain between three and six sites, [ 51,58–60 ] where each site has its own set of kinetic parameters, leading to different reaction rates and properties (e.g., chain length and comonomer fraction in the polymer). [ 61,62 ]…”

“…In general, the ZN catalysts are multi-sites, which leads to the production of polyolefins with broad MWD. Typically, these catalysts are said to contain between three and six sites, [51,[58][59][60] where each site has its own set of kinetic parameters, leading to different reaction rates and properties (e.g., chain length and comonomer fraction in the polymer). [61,62] Good overviews of the possible kinetic schemes in olefin polymerizations in slurry and gas phase ZN catalysts are given by Touloupidis [11] and Thakur et al [62] The elimination of some elementary steps is typically made to simplify the development of the kinetic model while retaining the ability to accurately estimate the overall polymerization rate and polymer average molecular weight.…”

A combined experimental and molecular simulation study on stress generation phenomena during the Ziegler–Natta polyethylene catalyst fragmentation process

“…35,36 On the other hand, the macroscopic modelling approaches are focusing on the selection of the operation conditions of the reactors to perform optimization studies. 5,[17][18][19][37][38][39][40][41][42][43][44] Two examples of this class of modeling approaches: The Polymer Flow (PF) models are a typical example of modeling aimed to predict the final polymer properties like MWD, CCD and of the reaction rate; 8,45 The Morphology models (MF) based on experimental information, like porometer data, [17][18][19] are used to describe how the fragmentation takes place during the polymerization reaction. 17,40,41,45,46 However, though they can well describe the fragmentation mechanism, they are not predictive "a priori" because experimental morphology information are needed at different stages of the process.…”