scholarly journals MARTINI-based simulation method for step-growth polymerization and its analysis by size exclusion characterization: a case study of cross-linked polyurethane

2019 ◽  
Vol 21 (38) ◽  
pp. 21603-21614 ◽  
Author(s):  
Hassan Ghermezcheshme ◽  
Hesam Makki ◽  
Mohsen Mohseni ◽  
Morteza Ebrahimi ◽  
Gijsbertus de With
Keyword(s):  
Network Formation ◽  
Simulation Method ◽  
Size Exclusion ◽  
Formation Mechanisms ◽  
Its Analysis ◽  
Step Growth ◽  
Step Growth Polymerization

Network formation mechanisms for cross-linked polyurethane with and without dangling chains.

Network Formation Kinetics of Poly(dimethylsiloxane) Based on Step-Growth Polymerization

2021 ◽  
Vol 54 (17) ◽  
pp. 7678-7689 ◽  
Author(s):  
Jie Jin ◽  
Ru-Qiu Zheng ◽  
Yin-Ning Zhou ◽  
Zheng-Hong Luo
Keyword(s):  
Network Formation ◽  
Formation Kinetics ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
Kinetics Of

scholarly journals Universal Relationships in Hyperbranched Polymer Architecture for Batch and Continuous Step Growth Polymerization of AB2-Type Monomers

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 220 ◽  
Author(s):  
Tobita
Keyword(s):  
Structural Characteristics ◽  
Simulation Method ◽  
Reactivity Ratio ◽  
Linear Molecule ◽  
Radius Of Gyration ◽  
Continuous Stirred Tank Reactor ◽  
Polymer Architecture ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
G Ratio

Design and control of hyperbranched (HB) polymer architecture by way of reactor operation is key to a successful production of higher-valued HB polymers, and it is essential in order to clarify the fundamental structural characteristics formed in representative types of reactors. In this article, the irreversible step growth polymerization of AB2 type monomer is investigated by a Monte Carlo simulation method, and the calculation was conducted for a batch and a continuous stirred-tank reactor (CSTR). In a CSTR, a highly branched core region consisting of units with large residence times is formed to give much more compact architecture, compared to batch polymerization. The universal relationships, unchanged by the conversion levels and/or the reactivity ratio, are found for the mean-square radius of gyration Rg2, and the maximum span length LMS. For batch polymerization, the g-ratio of Rg2 of the HB molecule to that for a linear molecule conforms to that for the random branched polymers represented by the Zimm-Stockmayer equation. A single linear equation represents the relationship between Rg2 and LMS, both for batch and CSTR. Appropriate process control in combination with the chemical control of the reactivity of the second B-group promises to produce tailor-made HB polymer architecture.

Using stable Mg isotopes to distinguish dolomite formation mechanisms: A case study from the Peru Margin

2014 ◽  
Vol 385 ◽  
pp. 84-91 ◽  
Author(s):  
Vasileios Mavromatis ◽  
Patrick Meister ◽  
Eric H. Oelkers
Keyword(s):  
Formation Mechanisms ◽  
Mg Isotopes ◽  
Dolomite Formation

scholarly journals Resin and carbon foam production by cationic step-growth polymerization of organic carbonates

2017 ◽  
Vol 8 (2) ◽  
pp. 404-413 ◽  
Author(s):  
L. Wöckel ◽  
A. Seifert ◽  
C. Mende ◽  
I. Roth-Panke ◽  
L. Kroll ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Controlled Release ◽  
Carbon Foam ◽  
Organic Carbonates ◽  
Step Growth ◽  
Step Growth Polymerization ◽  
Foam Production

Acid induced step-growth polymerizations of bis(p-methoxybenzyl) carbonate (pMBC), bis(m-methoxybenzyl) carbonate (mMBC) and difurfuryl carbonate (DFC) have been performed to produce resin-foams, because controlled release of carbon dioxide takes place during polymerization of those organic carbonates.

Designing Soft Reactive Adhesives by Controlling Polymer Chemistry

MRS Bulletin ◽  
2003 ◽  
Vol 28 (6) ◽  
pp. 424-427 ◽  
Author(s):  
Agnès Aymonier ◽  
Eric Papon
Keyword(s):  
Automotive Industry ◽  
Ease Of Use ◽  
Large Strains ◽  
Structural Adhesives ◽  
Wide Range ◽  
Step Growth ◽  
Visible Irradiation ◽  
Step Growth Polymerization ◽  
Uv Visible ◽  
Activation Heat

AbstractSoft reactive adhesives (SRAs) are polymer-based materials (e.g., polyurethanes, polysiloxanes, polydienes) designed to be further vulcanized or slightly cross-linked through external activation (heat, moisture, oxygen, UV–visible irradiation, etc.), either at the time of their application or within a subsequent predefined period. They are used mainly as mastics, or sealing compounds, in a wide range of industrial and commercial fields such as construction, footwear, and the automotive industry. Generally deposited as thick films, SRAs behave as structural adhesives; their low elastic moduli accommodate large strains between the bonded parts without incurring permanent damage. Other outstanding attributes of SRAs are their resistance to solvents, their ability to withstand aggressive environments, and their ease of use. This article discusses examples of SRAs and, more specifically, shows how the cross-linking chemistry, mainly through step-growth polymerization, provides their primary advantages.

scholarly journals A Simplified Simulation Method for Flood-Induced Bend Scour—A Case Study Near the Shuideliaw Embankment on the Cho-Shui River

Water ◽  
2017 ◽  
Vol 9 (5) ◽  
pp. 324 ◽  
Author(s):  
Wen-Dar Guo ◽  
Jian-Hao Hong ◽  
Cheng-Hsin Chen ◽  
Chih-Chiang Su ◽  
Jihn-Sung Lai
Keyword(s):  
Simulation Method

scholarly journals A look-ahead Monte Carlo simulation method for improving parental selection in trait introgression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saba Moeinizade ◽  
Ye Han ◽  
Hieu Pham ◽  
Guiping Hu ◽  
Lizhi Wang
Keyword(s):  
Monte Carlo ◽  
State Of The Art ◽  
Simulation Method ◽  
Multiple Trait ◽  
Look Ahead ◽  
Probability Of Success ◽  
Genetic Distribution ◽  
Selection Of ◽  
Trait Introgression

AbstractMultiple trait introgression is the process by which multiple desirable traits are converted from a donor to a recipient cultivar through backcrossing and selfing. The goal of this procedure is to recover all the attributes of the recipient cultivar, with the addition of the specified desirable traits. A crucial step in this process is the selection of parents to form new crosses. In this study, we propose a new selection approach that estimates the genetic distribution of the progeny of backcrosses after multiple generations using information of recombination events. Our objective is to select the most promising individuals for further backcrossing or selfing. To demonstrate the effectiveness of the proposed method, a case study has been conducted using maize data where our method is compared with state-of-the-art approaches. Simulation results suggest that the proposed method, look-ahead Monte Carlo, achieves higher probability of success than existing approaches. Our proposed selection method can assist breeders to efficiently design trait introgression projects.

Endothelial k-RasV12 Expression Induces Capillary Deficiency Attributable to Marked Tube Network Expansion Coupled to Reduced Pericytes and Basement Membranes

2021 ◽  
Author(s):  
Zheying Sun ◽  
Scott S. Kemp ◽  
Prisca K. Lin ◽  
Kalia N. Aguera ◽  
George E. Davis
Keyword(s):  
Protein Kinase ◽  
Basement Membrane ◽  
Arteriovenous Malformations ◽  
Network Formation ◽  
Tube Formation ◽  
Small Gtpase ◽  
Basement Membranes ◽  
Formation Mechanisms ◽  
Lumen Formation ◽  
The Impact

Objective: We sought to determine how endothelial cell (EC) expression of the activating k-Ras mutation, k-RasV12, affects their ability to form lumens and tubes and interact with pericytes during capillary assembly Approach and Results: Using defined bioassays where human ECs undergo observable tubulogenesis, sprouting behavior, pericyte recruitment to EC-lined tubes, and pericyte-induced EC basement membrane deposition, we assessed the impact of EC k-RasV12 expression on these critical processes that are necessary for proper capillary network formation. This mutation, which is frequently seen in human ECs within brain arteriovenous malformations, was found to markedly accentuate EC lumen formation mechanisms, with strongly accelerated intracellular vacuole formation, vacuole fusion, and lumen expansion and with reduced sprouting behavior, leading to excessively widened tube networks compared with control ECs. These abnormal tubes demonstrate strong reductions in pericyte recruitment and pericyte-induced EC basement membranes compared with controls, with deficiencies in fibronectin, collagen type IV, and perlecan deposition. Analyses of signaling during tube formation from these k-RasV12 ECs reveals strong enhancement of Src, Pak2 (P21 [RAC1 (Rac family small GTPase 1)] activated kinase 2), b-Raf (v-raf murine sarcoma viral oncogene homolog B1), Erk (extracellular signal–related kinase), and Akt activation and increased expression of PKCε (protein kinase C epsilon), MT1-MMP (membrane-type 1 matrix metalloproteinase), acetylated tubulin and CDCP1 (CUB domain-containing protein 1; most are known EC lumen regulators). Pharmacological blockade of MT1-MMP, Src, Pak, Raf, Mek (mitogen-activated protein kinase) kinases, Cdc42 (cell division cycle 42)/Rac1, and Notch markedly interferes with lumen and tube formation from these ECs. Conclusions: Overall, this novel work demonstrates that EC expression of k-RasV12 disrupts capillary assembly due to markedly excessive lumen formation coupled with strongly reduced pericyte recruitment and basement membrane deposition, which are critical pathogenic features predisposing the vasculature to develop arteriovenous malformations.

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