Macromolecular Theory and Simulations最新文献_第9页

Kinetic Monte Carlo Simulations as a Tool for Unraveling the Impact of Solvent and Temperature on Polymer Topology for Self-Initiated Butyl Acrylate Radical Polymerizations at High Temperatures 动力学蒙特卡罗模拟作为揭示溶剂和温度对高温下自引发丙烯酸丁酯自由基聚合聚合物拓扑影响的工具

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-18 DOI: 10.1002/mats.202300007

Jonas Mätzig, Marco Drache, Georg Drache, Sabine Beuermann

{"title":"Kinetic Monte Carlo Simulations as a Tool for Unraveling the Impact of Solvent and Temperature on Polymer Topology for Self-Initiated Butyl Acrylate Radical Polymerizations at High Temperatures","authors":"Jonas Mätzig, Marco Drache, Georg Drache, Sabine Beuermann","doi":"10.1002/mats.202300007","DOIUrl":"10.1002/mats.202300007","url":null,"abstract":"High-temperature butyl acrylate polymerizations in bulk and in solution are investigated experimentally and by kinetic Monte Carlo (kMC) simulations. The experimental data comprise conversion-time data, molar mass distributions, and branching levels per polymer chain derived from size-exclusion chromatography with a multiangle laser light scattering detector. A kMC model is established, which allows for the description of the impact of solvent and temperature on molar mass distribution as well as type and content of macromonomers. Within the study kinetic coefficients for transfer to solvent and the thermal self-initiation of the monomer are determined according to the Metropolis Hastings algorithm. The kMC simulations provide information, which are otherwise not accessible, for example, the number of branch points per molecule as a function of molar mass or the molar mass distribution of various macromonomer species. Moreover, molar ratios of mid-chain and chain-end radicals are at hand for temperatures up to 160°C, which are important for the interpretation of the experimentally and via simulation-derived polymer topology as a function of molar masses.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47951207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Dimensions of Network Polymers: Universal Relationship for the Ratio between Mean-Square Radius of Gyration and Graph Diameter 网络聚合物的尺寸：回转均方半径与图形直径之比的普遍关系

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-14 DOI: 10.1002/mats.202300012

Hidetaka Tobita

{"title":"Dimensions of Network Polymers: Universal Relationship for the Ratio between Mean-Square Radius of Gyration and Graph Diameter","authors":"Hidetaka Tobita","doi":"10.1002/mats.202300012","DOIUrl":"10.1002/mats.202300012","url":null,"abstract":"Mean-square radius of gyration Rg2 and the graph diameter D, which describe the dimensions of polymers, are investigated for the network polymers. Both for the random and nonrandom statistical networks whose cycle rank is r, a linear relationship Rg2 = ar D applies. The ratio ϕ of ar against the corresponding ring-free architecture a0, ϕr = ar/a0 has a universal relationship applicable both for the random and nonrandom networks with ϕr∝r−0.25 for large r’s, and an empirical relationship, ϕr = [(1 + r)−2/3 + r/2]−0.25 is proposed. For the polymer fraction having a given number of r, the nonrandom nature of crosslinking tends to make both Rg2 and D larger compared with the corresponding random networks, except for the limited cases with small values of r’s.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42805079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isolating the Effect of Crosslink Densities on Mechanical Properties of iPP Using DPD 用DPD分离交联密度对iPP力学性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-13 DOI: 10.1002/mats.202300014

Yoshitake Suganuma, J. Elliott

引用次数: 0

Isolating the Effect of Crosslink Densities on Mechanical Properties of Isotactic Polypropylene Using Dissipative Particle Dynamics 用耗散粒子动力学分离交联密度对等规聚丙烯力学性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-13 DOI: 10.1002/mats.202300014

Yoshitake Suganuma, James A. Elliott

{"title":"Isolating the Effect of Crosslink Densities on Mechanical Properties of Isotactic Polypropylene Using Dissipative Particle Dynamics","authors":"Yoshitake Suganuma, James A. Elliott","doi":"10.1002/mats.202300014","DOIUrl":"https://doi.org/10.1002/mats.202300014","url":null,"abstract":"Given the importance of preserving the mechanical properties of recycled isotactic polypropylene (iPP) during its processing, this work provides an improved understanding of the contribution of introducing physical or chemical crosslinks using the dissipative particle dynamics (DPD) method, which makes it possible to model iPP structures with a realistic range of crosslink densities. First, the protocol to build a coarse-grained model of iPP from an all-atom expression by Bayesian optimization is described. A Bayesian optimization procedure employing two different cutoff distances successfully provides optimal DPD parameters reproducing iPP's properties compared to the all-atom system. Then, the coarse-grained iPP model with optimal DPD parameters is applied to study structures containing a realistic range of crosslink densities to evaluate their mechanical properties. These calculations demonstrate that the mechanical properties such as the Young's modulus and ultimate strength increase while the fracture strain decreases with an increase in the crosslink density, which is consistent with experimental observations. The results also show that there is a critical crosslink density above which these properties start to be improved due to the introduction of crosslinks. These findings can help us to obtain targeted properties of recycled iPP by introducing physical or chemical crosslinks.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50130998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Volumetric and Energetic Properties of Polystyrene and Polyethylene Oxide Affected by Thermal Cycling 热循环对聚苯乙烯和聚氧乙烯体积和能量性能的影响

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-04-06 DOI: 10.1002/mats.202300008

Benoit Minisini, Armand Soldera

{"title":"Volumetric and Energetic Properties of Polystyrene and Polyethylene Oxide Affected by Thermal Cycling","authors":"Benoit Minisini, Armand Soldera","doi":"10.1002/mats.202300008","DOIUrl":"10.1002/mats.202300008","url":null,"abstract":"Polymers are known to exhibit hysteresis in their thermal and volumetric properties between cooling and heating at the glass transition. A thorough investigation of this hysteresis using atomistic simulation is not proposed until now. In this work, therefore, the glass transition is studied through heating and cooling protocols at constant rate for two polymers, polystyrene (PS) and polyethylene oxide (PEO), with different molecular weights. To achieve this objective, the analysis is carried out by plotting against temperature, specific volume, coefficient of thermal expansion, total energy, and constant volume heat capacity. The calculated properties for PS and PEO are found to be in good agreement with experimental data, confirming the accuracy of the TraPPE force field for these polymers. The glass transition temperature (Tg) range remains the same regardless of the properties. Moreover, the difference in properties between heating and cooling processes systematically leads to a peak at the same temperature, associated with Tg. Finally, starting from a low temperature, the polymer chains remain mainly in a potential well as the temperature rises, while during cooling the exploration of the configuration space continues up to the temperature where no torsional changes are observed.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 4","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202300008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45275990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Masthead: Macromol. Theory Simul. 2/2023 刊头：Macromol。理论模拟。2023年2月

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-03-20 DOI: 10.1002/mats.202370004

引用次数: 0

Molecular Simulation and Experimental Study on the Damping and Aging Properties of 4010NA/Hydrogenated Nitrile Butadiene/Nitrile Butadiene Rubber Composites 4010NA/氢化丁腈/丁腈橡胶复合材料阻尼老化性能的分子模拟与实验研究

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-03-20 DOI: 10.1002/mats.202370003

Meng Song, Meng Wang, Chaole Wang, Jihong Song, Yunan Li, Fengyi Cao, Guomin Yu, Qi Qin

引用次数: 0

Monte Carlo Simulation of Long Hard-Sphere Polymer Chains in Two to Five Dimensions 二至五维长硬球聚合物链的蒙特卡罗模拟

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-03-18 DOI: 10.1002/mats.202200080

Stefan Schnabel, Wolfhard Janke

引用次数: 1

Retrosynthetic and Synthetic Reaction Prediction Model Based on Sequence-to-Sequence with Attention for Polymer Designs 注意聚合物设计的基于序列对序列的反合成和合成反应预测模型

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-03-17 DOI: 10.1002/mats.202300011

Hiroaki Taniwaki, Hiromasa Kaneko

引用次数: 0

Atomistic MD Simulations of n-Alkanes in a Phospholipid Bilayer: CHARMM36 versus Slipids 磷脂双层中n-烷烃的原子MD模拟：CHARMM36与Slipid

IF 1.4 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2023-03-12 DOI: 10.1002/mats.202200078

Anika Wurl, Tiago M. Ferreira

{"title":"Atomistic MD Simulations of n-Alkanes in a Phospholipid Bilayer: CHARMM36 versus Slipids","authors":"Anika Wurl, Tiago M. Ferreira","doi":"10.1002/mats.202200078","DOIUrl":"10.1002/mats.202200078","url":null,"abstract":"Linear alkanes (n-alkanes) are chemically the most simple linear hydrophobic molecules in nature. Studying the incorporation of n-alkanes into lipid membranes is therefore a good starting point toward understanding the behavior of hydrophobic molecules in lipid membranes and to assess how accurately molecular dynamics models describe such systems. Here, the miscibility and structure of different n-alkanes—n-decane (C10), n-eicosane (C20), and n-triacontane (C30)—in dipalmitoylphosphatidylcholine membranes are investigated using two of the most used force fields for lipid membrane molecular dynamics simulations (CHARMM36 and Slipids). The n-alkanes are miscible in the membrane up to a critical volume fraction, ϕc, that depends on the force field interaction parameters used. ϕc is dependent on alkane chain length only for the model with more disordered chains (Slipids). Below ϕc, a comparison with 2H nuclear magnetic resonance (NMR) spectra indicates that a more realistic structure of the longer alkane molecules (C20 and C30) is obtained using the Slipids force field. On the other hand, for the shorter alkane (C10), Slipids simulations underestimate molecular order and CHARMM36 simulations enable a precise prediction of its experimental spectrum. The predicted 2H NMR spectra are highly sensitive to 1–4 electrostatic interactions, and suggest that a reduction of the partial charges of the longer alkanes and acyl chains in CHARMM36 results in a better performance. The results presented indicate that lipid membranes with incorporated alkanes are highly valuable systems for the validation of force fields designed to perform lipid membrane simulations.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"32 3","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202200078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47374056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0