The selectivity of nanoparticles for polydispersed ligand chains during the grafting-to process: a computer simulation study

2018 ◽  
Vol 20 (3) ◽  
pp. 2066-2074 ◽  
Author(s):  
Ji-Yuan Xing ◽  
Zhong-Yuan Lu ◽  
Hong Liu ◽  
Yao-Hong Xue
Keyword(s):  
Computer Simulation ◽  
Chain Length ◽  
Simulation Study ◽  
Length Distribution ◽  
Reaction Model ◽  
Polymer Chains ◽  
Polydispersity Index ◽  
Computer Simulation Study ◽  
Chain Length Distribution ◽  
Grafting Density

By constructing a grafting-to reaction model of polydispersed polymer chains to bind onto nanoparticles (NPs), we elucidate the changes of grafting density, polydispersity index and chain length distribution of grafted ligand chains as a dependence of the feeding polymer chains.

scholarly journals Method of Moments Applied to Most-Likely High-Temperature Free-Radical Polymerization Reactions

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 656 ◽  
Author(s):  
Hossein Riazi ◽  
Ahmad Arabi Shamsabadi ◽  
Michael Grady ◽  
Andrew Rappe ◽  
Masoud Soroush
Keyword(s):  
High Temperature ◽  
Free Radical ◽  
Radical Polymerization ◽  
Chain Length ◽  
Method Of Moments ◽  
Length Distribution ◽  
Free Radical Polymerization ◽  
Polymer Chains ◽  
Rate Equations ◽  
Chain Length Distribution

Many widely-used polymers are made via free-radical polymerization. Mathematical models of polymerization reactors have many applications such as reactor design, operation, and intensification. The method of moments has been utilized extensively for many decades to derive rate equations needed to predict polymer bulk properties. In this article, for a comprehensive list consisting of more than 40 different reactions that are most likely to occur in high-temperature free-radical homopolymerization, moment rate equations are derived methodically. Three types of radicals—secondary radicals, tertiary radicals formed through backbiting reactions, and tertiary radicals produced by intermolecular chain transfer to polymer reactions—are accounted for. The former tertiary radicals generate short-chain branches, while the latter ones produce long-chain branches. In addition, two types of dead polymer chains, saturated and unsaturated, are considered. Using a step-by-step approach based on the method of moments, this article guides the reader to determine the contributions of each reaction to the production or consumption of each species as well as to the zeroth, first and second moments of chain-length distributions of live and dead polymer chains, in order to derive the overall rate equation for each species, and to derive the rate equations for the leading moments of different chain-length distributions. The closure problems that arise are addressed by assuming chain-length distribution models. As a case study, β-scission and backbiting rate coefficients of methyl acrylate are estimated using the model, and the model is then applied to batch spontaneous thermal polymerization to predict polymer average molecular weights and monomer conversion. These predictions are compared with experimental measurements.

Enhancement of surface nonwettability by grafting loops

2017 ◽  
Vol 19 (6) ◽  
pp. 4710-4718 ◽  
Author(s):  
Han-Wen Pei ◽  
Xiao-Li Liu ◽  
Hong Liu ◽  
You-Liang Zhu ◽  
Zhong-Yuan Lu
Keyword(s):  
Computer Simulation ◽  
Simulation Study ◽  
Flat Surface ◽  
Polymer Chains ◽  
Computer Simulation Study

We present a computer simulation study on the nonwettability of a flat surface tethered with deformable looped polymer chains.

Polymer-grafted nanoparticles prepared via a grafting-from strategy: a computer simulation study

2018 ◽  
Vol 20 (27) ◽  
pp. 18400-18409 ◽  
Author(s):  
Long Li ◽  
Cheng Han ◽  
Dan Xu ◽  
Ji-Yuan Xing ◽  
Yao-Hong Xue ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulation ◽  
Reaction Model ◽  
Polymer Chains ◽  
Coarse Grained ◽  
Computer Simulation Study ◽  
Grafted Nanoparticles ◽  
Dynamics Simulations ◽  
Grafting From ◽  
Stochastic Reaction

Nanoparticles (NPs) grafted with polymer chains prepared via a grafting-from strategy are studied through coarse-grained molecular dynamics simulations combined with our stochastic reaction model.

Direct Observation of Chain Lengths and Conformations in Oligofluorene Distributions from Controlled Polymerization by Double Electron-Electron Resonance

2019 ◽  
Author(s):  
Dennis Bücker ◽  
Annika Sickinger ◽  
Julian D. Ruiz Perez ◽  
Manuel Oestringer ◽  
Stefan Mecking ◽  
...  
Keyword(s):  
Chain Length ◽  
Length Distribution ◽  
Catalyst System ◽  
Chain Conformation ◽  
Controlled Polymerization ◽  
Chain Length Distribution ◽  
Electron Resonance ◽  
Double Electron ◽  
The Individual ◽  
Double Electron Electron Resonance

Synthetic polymers are mixtures of different length chains, and their chain length and chain conformation is often experimentally characterized by ensemble averages. We demonstrate that Double-Electron-Electron-Resonance (DEER) spectroscopy can reveal the chain length distribution, and chain conformation and flexibility of the individual n-mers in oligo-(9,9-dioctylfluorene) from controlled Suzuki-Miyaura Coupling Polymerization (cSMCP). The required spin-labeled chain ends were introduced efficiently via a TEMPO-substituted initiator and chain terminating agent, respectively, with an in situ catalyst system. Individual precise chain length oligomers as reference materials were obtained by a stepwise approach. Chain length distribution, chain conformation and flexibility can also be accessed within poly(fluorene) nanoparticles.

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