Modeling of High‐Pressure Ethene Homo‐ and Copolymerization

Abstract

While reaction engineering of low‐molecular weight compounds mainly focuses on equilibria and selectivities, polymer properties are tremendously influenced by molecular weight distribution as well as branching structure. In order to determine the branching structure of low‐density polyethylene (LDPE) copolymers in dependence on chosen process conditions, a Monte‐Carlo approach was developed. By modeling the topology as well as the comonomer distribution in the polymer chains a deeper insight in the process‐microstructure‐properties relationship is gained.

Modeling of the Free Radical Copolymerization Kinetics of n-Butyl Acrylate, Methyl Methacrylate and 2-Ethylhexyl Acrylate Using PREDICI®

“…The adjustments carried out to eliminate induction times from experimental data may be an issue here. However, on a closer look, it is inferred from Table 9, that although the reactivity ratios at zero conversion coincide with the available ones, the fact that different free volume parameters (β values) for the cross-propagation terms were used, that causes the ratios to change (according to Equation (29); ratios of kpi 0 remain unchanged, but since the βs are different, the actual ratios do not remain constant). However, as observed in Figures 15-17, the same does not hold entirely true for the terpolymerization cases.…”

“…conditions for the bulk terpolymerization of BA, EHA and MMA at 60 °C. Tables 5-7 show the reaction steps used in PREDICI ® (version 11.Hilbert.4, Computing in Technology, CiT, Rastede, Lower Saxony, Germany), a software commonly used in polymer science and engineering [27][28][29]. The copolymerization schemes for the three studied systems (BA/EHA, EHA/MMA, BA/EHA/MMA) are based on conventional bulk free-radical copolymerization kinetics, but takeinto consideration the nature of each system, such as the occurrence of certain side reactions (e.g., backbiting for BA [25], the presence of additional cross reactions for the terpolymer, and building on previous knowledge on MMA and BA homo-and copolymerizations [19,20,25].…”

“…All the reactions involving polymer molecules were assumed to be diffusion-controlled. DC effects were addressed using free-volume theory [25,40], as shown in Equation 28, where β is a free volume parameter andv f is fractional free volume, defined by Equation (29). Subscript "0" stands for initial conditions.…”

Model‐Assisted Optimization of RAFT Polymerization in Micro‐Scale Reactors—A Fast Screening Approach

“…Polymers are versatile materials that are used in countless applications in daily life. The polymers used range from bulk plastics such as various polyolefines [ 1–5 ] to block copolymers specialized in various fields of applications. [ 6–14 ] Polymer properties depend on their chemical composition (i.e., homopolymers, random or gradient copolymers, block copolymers), their topology (i.e., linear, branched, cyclic), and their molecular weight distribution (MWD).…”

Modeling Semi-Batch Vinyl Acetate Polymerization Processes

“…Moreover, enormous advances in the development of simulation methods in recent years contributed significantly to a better understanding of the exact reaction mechanism; e.g., a better understanding of the backbiting reaction in acrylate polymerizations is reached by comparing the actual measured and simulated data. 3,5,6,9,15−28 In particular, state-of-the-art in silico Monte Carlo methods 3,5,6,9,[16][17][18][19][20][21][22][23][24][25][26]29,30 allow us to predict the microstructure of an ensemble of isolated polymer chains. 31 Kinetic Monte Carlo simulations have already been applied to challenges in chemical engineering.…”