The Relevance of Multi‐Injection and Temperature Profiles to Design Multi‐Phase Reactive Processing of Polyolefins

Abstract

For industrial‐scale continuous free radical induced grafting of polyethylene, which involves the contact of a monomer‐ and polymer‐rich phase, it is demonstrated that the functionalization selectivity and grafting density can be significantly improved (e.g., 100%) by considering multiple injection of monomer and/or a temperature profile. With parameters taken from literature, it is highlighted through simulations that step‐wise addition of monomer allows to reduce the homopolymerization rate, and an increased temperature at the start of the reactive processing allows to increase the hydrogen abstraction rate, so that more potential grafting points can be generated. As this increased grafting density goes along with a lower reaction extent, a better process efficiency is obtained albeit at a lowering of the average chain length of the grafts and an increase of the crosslinking density. In any case, a broader span of polymer characteristics (e.g., ranges of grafting/crosslinking densities and functionalization yields) can be achieved by including variations in reactant addition and temperature profiles.

Gillespie-Driven kinetic Monte Carlo Algorithms to Model Events for Bulk or Solution (Bio)Chemical Systems Containing Elemental and Distributed Species

“…One of the most versatile advanced data structures for storing and fast recovery of information is the binary tree, which is taken from the mathematical graph theory as a subdiscipline of discrete mathematics. , This univariate data structure has been used in database applications, physics, and information network systems . For polymerization systems, it has been successfully used to represent distributed characteristics, e.g., the chain length, copolymer composition, functional group, or branch distribution, ,,,, and to facilitate the selection of reaction channels in SSA ,− and reactant microspecies. ,, …”

“…207 For polymerization systems, it has been successfully used to represent distributed characteristics, e.g., the chain length, copolymer composition, functional group, or branch distribution, 66,82,124,198,208 and to facilitate the selection of reaction channels in SSA 66,208−210 and reactant microspecies. 82,117,211 The so-called complete or perfect binary tree is a graph in which each parent node except the bottom ones (the leaves) has two children, and every leaf is equally distant from the root node, implying that the leaves are at the same height. 67 This is conceptually depicted in Figure 6, focusing at the leaf level on the representation of a number population on a chain length (i) basis.…”

Extending Multilevel Statistical Entropy Analysis towards Plastic Recyclability Prediction

“…Reactive extrusion and multiphase blending with extrusion technology is currently being developed to combine the recycling of polymers or plastic waste and synthesize new polymers or plastic products [52][53][54]. Similarly, reactive extrusion typically keeps the system at a high relative statistical entropy state but offers benefits from an energetic point of view compared with other technologies (that aim at reducing the entropy) for the same waste stream.…”

Exploiting (Multicomponent) Semibatch and Jacket Temperature Procedures to Safely Tune Molecular Properties for Solution Free Radical Polymerization of n‐Butyl Acrylate

“…[ 49,67 ] A more novel implementation pathway is the formal consideration of a pseudo‐zeroth‐order chemical reaction, which is being sampled in the k MC algorithm along with all chemical reaction types. [ 39 ] Such approach ensures the irrelevance of spikes in species’ concentrations even if the initial loads are small (e.g., 10% of total amount) [ 39,68 ] and allows to speed‐up the calculations as smaller numbers of molecules are required for high accuracy simulation results. In the present study, we however use the traditional approach of updating the number of molecules at predetermined time steps at which addition is assumed to instantaneously take place.…”