Molecular Weight Distribution Simulation in Equilibrium Ring‐Opening Polymerization: A New Macroscopic Model

Long, Teng; Zhang, Chen; Liu, Hui; Chen, Xin; Zhao, Shigui; Zhou, Chuanjian

doi:10.1002/mats.201700057

Cited by 5 publications

(2 citation statements)

References 32 publications

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“…When polymers are synthesized in solution, a variety of strategies for modulating Đ within a broad range of values have been proposed . Established methods included blending polymers with different molar masses, − the application of uncontrolled polymerizations, or the modulation of polymerization kinetics. − More recent developments in RDRP methods enabled to predict − and finely tune Đ during solution polymerization, especially by the adjusting the catalytic system, − initiation, − or termination processes. , Translation of these methods into efficient ways to modulate the dispersity of polymer brushes is not straightforward and suffers from intrinsic limitations characterizing the corresponding surface-initiated processes. One is the extremely low concentration of initiator/propagating species confined at the surface during brush growth.…”

Section: Brush Parameters: What Seems To Mattermentioning

confidence: 99%

Opportunities, Challenges, and Pitfalls in Making, Characterizing, and Understanding Polymer Brushes

Pester,

Klok,

Benetti

2023

Macromolecules

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Section: Brush Parameters: What Seems To Mattermentioning

confidence: 99%

Opportunities, Challenges, and Pitfalls in Making, Characterizing, and Understanding Polymer Brushes

Pester,

Klok,

Benetti

2023

Macromolecules

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“…[20] To better understand the connection between kinetics and MWD as well as to clarify which theory is correct or more proper, many efforts have been made to simulate MWD. [11,12,16,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Three methods, i.e., moments, Monte Carlo, and solving ordinary differential equations directly, have been developed. [14,16] Among them, the most used is the method of moments because it is not only based on clear reaction mechanism and kinetic equation, but also ratio (RR) of chain propagation to chain transfer can give an impact on the degree of uniformity of chain length.…”

Section: Introductionmentioning

confidence: 99%

Molecular Weight Distribution in Ring‐Opening Polymerization of Propylene Oxide Catalyzed by Double Metal Complex: A Model Simulation

Zhao

Fan

2021

Macro Theory & Simulations

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easy to calculate. Even though this method cannot show out the full MWD curves, it gathers the most important information such as monomer conversion (x), molecular weight (MW), and polydispersity index (PDI). [28] PDI quantifies the width of MWD.The ring-opening polymerization (ROP) of propylene oxide (PO) catalyzed by double metal complex (DMC) is generally considered to have the characteristics of living polymerization. For example, the MW increases with x, and block copolymers with ethylene oxide can be prepared. However, our recent experimental study shows that the MWD of products is not easy to keep very narrow even if the polymerization is carried out in batch or plug flow reactor. [34] According to the polymerization mechanism proposed by Huang et al., [35][36][37] it is generally believed that the chain transfer reaction between active chains and dormant chains is the key to narrow MWD. However, up to now, no one has quantitatively investigated the effect of this chain transfer reaction on the MWD.In this work, a kinetic model involving chain propagation and chain transfer is established; the method of moments is used to simulate PDI as well as x and number-average polymerization degree (Xn) under various reaction conditions. We hope that this work can facilitate the understanding of the polymerization mechanism behind various complex phenomena in the ROP catalyzed by DMC. Modeling Section Polymerization MechanismAs Huang et al. [35][36][37] and Kim et al. [38,39] have reported, ROP of PO catalyzed by DMC consists of induction, chain propagation, and transfer reaction. Herein, only the chain propagation and transfer reaction are considered since they are the main reactions that affect MWD. As shown in Scheme 1, chains with active center can be propagated; meanwhile, the active center can be transferred to dormant chains so that they are activated and propagated. It is the chain transfer between the active chain and dormant chain that results in the more uniform chain growth. Obviously, it can be thought that the instant rate In the present work, method of moments is used to model the molecular weight distribution (MWD) of polypropylene glycol (PPG) produced with ring-opening polymerization of propylene oxide catalyzed by double metal complex (DMC), and an explicit expression about the polydispersity index (PDI) of PPG is obtained. The simulated results indicate that decreasing the initial concentration ratio of monomer to total chains (K 1 ) or increasing the rate constant ratio of chain transfer to propagation (K 2 ) leads to smaller PDI. Reducing the concentration of DMC can induce larger PDI. When the PPG's initial PDI (i.e., PDI of initiator) increases, PDI of the final PPG grows up linearly. However, with the increase of monomer conversion, PDI increases first and then decreases, that is, there is a critical conversion. The possible lack of chain transfer at the beginning of polymerization and the insufficient chain transfer caused by increased K 1 , decreased concentration of catalyst, and decreased...

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Modulation of Polymer Brush Properties by Tuning Dispersity

Pester

Benetti

2022

Adv Materials Inter

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physicochemical properties of the generated surfaces, in addition to grafting density, molar mass, and topology (or polymer architecture) (Figure 1). More generally, a variation of Đ within a brush can be exploited to modulate the way brushfunctionalized nanomaterials interact with the surrounding environment, within suspensions or composites.While the effects of a variation in grafted chain Đ on the conformation of polymer brushes and their properties have been addressed in various theoretical and computational studies, limited experimental studies have addressed this issue systematically so far. Nonetheless, a clear dependence on Đ of technologically relevant properties such as steric stabilization, lubrication, and biopassivity by polymer brushes has been identified. Here we summarize these effects, focusing on those displayed by both brushes grafted on nanoparticles (NPs) (also named "spherical brushes") and on macroscopic surfaces, and also highlight how a more precise control of brush Đ could be exploited synthetically in future studies to modulate the characteristics of interfaces and materials.

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Molecular Weight Distribution Simulation in Equilibrium Ring‐Opening Polymerization: A New Macroscopic Model

Cited by 5 publications

References 32 publications

Opportunities, Challenges, and Pitfalls in Making, Characterizing, and Understanding Polymer Brushes

Opportunities, Challenges, and Pitfalls in Making, Characterizing, and Understanding Polymer Brushes

Molecular Weight Distribution in Ring‐Opening Polymerization of Propylene Oxide Catalyzed by Double Metal Complex: A Model Simulation

Modulation of Polymer Brush Properties by Tuning Dispersity

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