Macromolecular Theory and Simulations最新文献_第2页

Masthead: Macromol. Theory Simul. 6/2024 刊头：Macromol.理论模拟6/2024

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-11-18 DOI: 10.1002/mats.202470012

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The Logistic Function in Glass Transition Models of Amorphous Polymers: A Theoretical Framework for Isobaric Cooling Processes 无定形聚合物玻璃转化模型中的对数函数：等压冷却过程的理论框架

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-11-18 DOI: 10.1002/mats.202470011

Claudio Corbisieri

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Copolymer Randomization by End-Group Interchain Exchange Reactions

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-11-05 DOI: 10.1002/mats.202400072

Yaroslav V. Kudryavtsev

{"title":"Copolymer Randomization by End-Group Interchain Exchange Reactions","authors":"Yaroslav V. Kudryavtsev","doi":"10.1002/mats.202400072","DOIUrl":"https://doi.org/10.1002/mats.202400072","url":null,"abstract":"Theoretical analysis of the kinetic scheme describing formation and randomization of a binary copolymer due to end-group interchange reactions is presented. Compact analytical expressions are obtained for the transient and equilibrium values of the copolymer degree of blockiness and fractions of active end-groups of different types. The resulting copolymer is described by the first-order Markov statistics, which can be rather far from the Bernoullian one. Its structure is determined by the composition of the system and a single combination of the rate constants of four elementary reactions. The kinetics includes fast and slow stages with characteristic time periods independent of and proportional to the average polymerization degree, respectively. During the fast stage, the initial polymers disappear, whereas the copolymer degree of blockiness is still very low. The distribution of units in the copolymer is Markovian, only if the initial polymers possess the most probable molar mass distributions. At the slow stage copolymer randomization gradually progresses, whereas the distribution of end groups may change in the opposite direction compared to the fast stage. The results can be used to analyze the experimental data on the chain structure of condensation, metathesis, and dynamic covalent polymers, where interchange reactions play a significant role.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143112374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Role of Cyclic Ketene Dithioacetals in Free Radical Polymerization of Vinyl Chloride

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-10-01 DOI: 10.1002/mats.202400063

Mohammad Bajbouj, Ouiem Jalil, Isa Degirmenci

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The Logistic Function in Glass Transition Models of Amorphous Polymers: A Theoretical Framework for Isobaric Cooling Processes 无定形聚合物玻璃转化模型中的对数函数：等压冷却过程的理论框架

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-25 DOI: 10.1002/mats.202400052

Claudio Corbisieri

{"title":"The Logistic Function in Glass Transition Models of Amorphous Polymers: A Theoretical Framework for Isobaric Cooling Processes","authors":"Claudio Corbisieri","doi":"10.1002/mats.202400052","DOIUrl":"https://doi.org/10.1002/mats.202400052","url":null,"abstract":"Studying the macroscopic-phenomenological behavior of amorphous polymers at glass transition is often subject to limitations because the ordinary differential equations that describe the material behavior require numerical solution. To avoid these limitations, ad-hoc-formulated models of the glass transition have been proposed. However, their scope of application is expected to be limited due to insufficient theoretical foundation. This work establishes a theoretical framework for models that use the logistic function to approximate the macroscopic-phenomenological behavior of amorphous polymers at glass transition. For this purpose, an exactly-solvable Riccati equation is derived within thermodynamics with internal state variables. A closed-form expression in terms of mathematical functions for the temperature derivative of a single internal state variable is the result. This closed-form expression contains the logistic function thus featuring a continuous transition region centered around a pressure and cooling-rate dependent transition temperature. Based on comparison of existing models with the exact solution derived from the Riccati equation, generalized models that approximate the thermal expansion coefficient and heat capacity at glass transition are proposed. This work thus demonstrates the validity of the logistic function in glass transition models of amorphous polymers and provides suggestions as to how existing models can be extended in their applicability.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"33 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202400052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142666085","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}

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Investigating the Effect of Rheological Parameter Ratios on the Mixing Properties of TPU Blends 研究流变参数比对热塑性聚氨酯混合物混合性能的影响

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-16 DOI: 10.1002/mats.202470009

Yiwen Zheng, Jiankang Wang, Chenyang Wang, Zhijun Li, Zuliang Yang

引用次数: 0

Heat Transfer Analysis of the Blade Coating Process Using Oldroyd 4-Constant Nanofluid Model With Non-Linear Slip and Magnetohydrodynamics (MHD) Effects

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-16 DOI: 10.1002/mats.202400067

Muhammad Asif Javed, Hammad Khalil, Abuzar Ghaffari

{"title":"Heat Transfer Analysis of the Blade Coating Process Using Oldroyd 4-Constant Nanofluid Model With Non-Linear Slip and Magnetohydrodynamics (MHD) Effects","authors":"Muhammad Asif Javed, Hammad Khalil, Abuzar Ghaffari","doi":"10.1002/mats.202400067","DOIUrl":"https://doi.org/10.1002/mats.202400067","url":null,"abstract":"Blade coating is a process that applies a fluid to a surface using a fixed blade. Among various coating technologies, blade coating offers significant economic advantages. It is commonly employed in the production of paper, information preservation, the application of coloring agents, and the manufacture of photographic films and magnetic storage devices. The novelty of this work lies in the investigation of the blade coating process for an electrically conducting Oldroyd 4-constant liquid, incorporating velocity slippage at the blade surface in an area previously underexplored. The mathematical equations are modeled with the use of Lubrication Approximation Theory (LAT) and the normalized equations of the Oldroyd 4-constant fluid are numerically solved by the Matlab built-in function bvp4c using Regula-Falsi Method. The impact of sundry parameters on physical quantities is examined through graphical representation. It is noted from the theoretical results that for the fixed value of the MHD parameter (M = 2.5), the coating thickness and blade load increased by 31% and 1648% respectively, for plane coater. For the exponential coater, these values increased by 29% and 1618% from their Newtonian value. These findings offer new insights into optimizing the blade coating process for complex fluid systems.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 1","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143115658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Masthead: Macromol. Theory Simul. 5/2024 刊头：Macromol.理论模拟5/2024

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-16 DOI: 10.1002/mats.202470010

引用次数: 0

Rheological Equivalent Circuit Model Using Electrochemical Impedance Analysis 利用电化学阻抗分析的流变等效电路模型

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-08 DOI: 10.1002/mats.202400069

Hwan Woo Choi, Young Seok Song

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Effect of Hydrolyzed Polyacrylamide on the Emulsion Stability by Multiple Light Scattering and Molecular Dynamics Simulation 通过多重光散射和分子动力学模拟研究水解聚丙烯酰胺对乳液稳定性的影响

IF 1.8 4区工程技术

Macromolecular Theory and Simulations Pub Date : 2024-09-05 DOI: 10.1002/mats.202400040

Jin Huang, Xiaorong Ma, Hongyao Li, Mengxue Liu, Qinghe Gao, Cuiqin Li

{"title":"Effect of Hydrolyzed Polyacrylamide on the Emulsion Stability by Multiple Light Scattering and Molecular Dynamics Simulation","authors":"Jin Huang, Xiaorong Ma, Hongyao Li, Mengxue Liu, Qinghe Gao, Cuiqin Li","doi":"10.1002/mats.202400040","DOIUrl":"10.1002/mats.202400040","url":null,"abstract":"Polymer flooding, using hydrolyzed polyacrylamide (HPAM), is crucial in enhanced oil recovery technology. The effect of the HPAM and NaCl concentration on the stability of the simulated emulsions was assessed through multiple light scattering experiments. The results demonstrated that HPAM significantly enhanced the stability of both oil-in-water (O/W) and water-in-oil (W/O) emulsions. The HPAM concentration escalated from 200 mg L−1 to 1000 mg L−1, increasing from 1.24% to 1.31% at 60 minute in the average backscattering of W/O emulsions. The average transmittance of O/W emulsions exhibited a significant decline from 2.54% to 0.12%. The NaCl concentration had a small effect on the stability of the emulsions. Molecular dynamics simulations revealed that HPAM adsorbed at the oil water interface by the point-like nature, with stronger interaction between its amide group and the oil molecule than its carboxyl group. The hydrogen bond number and the hydrogen bond lifetime of HPAM-H2O and HPAM-HPAM increase with increasing the number of HPAM molecules at the oil-water interface, slowing diffusion coefficient of water molecules and increasing the interface thickness. Increasing salinity can weaken the HPAM-water interaction, reducing the emulsification stability. This work provides insights into the emulsification characteristics and mechanisms of HPAM.","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"33 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0