Macromolecular Theory and Simulations最新文献

{"title":"Aging of Tetrafluoroethylene Propylene (FEPM) Material in High-Pressure HighTemperature Hydrogen Sulfide Downhole Environment: Theory, Modeling, Experiments, and Material Lifetime Prediction","authors":"Aref Ghaderi,&nbsp;Hadis Nouri,&nbsp;Roozbeh Dargazany,&nbsp;Scott Meng,&nbsp;Peixiang Xing,&nbsp;Jiaxiang Ren,&nbsp;Peng Cheng","doi":"10.1002/mats.202500044","DOIUrl":"https://doi.org/10.1002/mats.202500044","url":null,"abstract":"<p>This paper presents a physics-driven neural network (PINN) model to capture the constitutive behavior, elongation at break (EAB), modulus, and tensile strength of FEPM material in high-pressure, high-temperature (HPHT) hydrogen sulfide (H2S) downhole environment. The model comprises a deep neural network structure and a physics-based constitutive equation. The PINN model was trained using experimental data from the FEPM material properties before and after the ISO-23936-2 immersion tests. It is shown that the PINN model can accurately predict the FEPM material behavior under HPHT sour service conditions. The predictions of our DL model agree well with the experimental data. Predictions were also made via the Arrhenius approach per ISO 23936-2 based on the same data set, and the results were compared to those from the PINN model. The comparison highlights that the Physics-Informed Neural Network (PINN) model excels in predicting material longevity across a broad temperature spectrum. This research underscores the effectiveness of PINN models in precisely forecasting material performance in high-pressure, high-temperature (HPHT) sour downhole conditions, paving the way for the development of advanced materials.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"35 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202500044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145909193","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}

{"title":"Effect of Weight Functions on the Dynamics and Rheology of Dilute Polymer Solutions in Dissipative Particle Dynamics Simulations","authors":"Sanjay Jana,&nbsp;Indranil Saha Dalal","doi":"10.1002/mats.202500071","DOIUrl":"https://doi.org/10.1002/mats.202500071","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;Dissipative particle dynamics (DPD) is a mesoscale simulation technique that has shown promise for studying polymer solutions, particularly in complex flow geometries. However, its application in rheological studies of polymer solutions remains limited compared to Brownian dynamics (BD) simulations. This is partly due to lack of investigations of the effect of modeling parameters on rheological results, in flow fields. This study investigates the influence of the weight function parameter &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;annotation&gt;$s$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; in DPD simulations on the behavior of dilute polymer solutions, comparing the conventional value &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$s = 2$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$s = 0.5$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, which has been suggested to better mimic liquid-like behavior. We perform detailed DPD simulations at equilibrium and under flow conditions, including both extensional and shear flows, using a highly resolved polymer chain model. Our results show that while the equilibrium chain size predictions are nearly identical for both &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;annotation&gt;$s$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; values, the dynamics differ significantly. Specifically, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$s = 0.5$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; results in slower chain relaxation times and suppresses excluded volume effects. Drag forces with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$s = 0.5$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; are larger, leading to higher chain stretch at moderate flow rates. With start-up extension, the time distribution for unraveling with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;0.5&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$s = 0.5$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; remains significantly narrow, with no outlier configurations with delayed stretching. In shear flows, the end-over-end tumbling dynamics is slower with &lt;span&gt;&lt;/span&gt;&lt;math","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"35 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145964326","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}

{"title":"Effect of Patch Size and Attraction Energy on Polymer Chain Adsorption in Slits Created by Opposing Patch-Patterned Surfaces","authors":"Han-Da Liu,&nbsp;Shuai Li,&nbsp;Qing-Hui Yang,&nbsp;Meng-Bo Luo","doi":"10.1002/mats.202500076","DOIUrl":"https://doi.org/10.1002/mats.202500076","url":null,"abstract":"<div>\u0000 \u0000 <p>The adsorption behavior of a polymer chain within a slit composed of two patch-patterned surfaces is investigated using Langevin dynamics simulations. Each surface exhibits periodic attractive square patches (period <i>d</i>, size <i>L</i>, attraction energy ε_ps), with a 0.5<i>d</i> misalignment between the two surfaces. The adsorption degree increases with <i>L</i>, while the mean number of occupied patches &lt;<i>n</i>_pa&gt; and the surface-parallel component of the mean square radius of gyration &lt;<i>R</i>²_g,xy&gt; exhibit a complex dependence on <i>L</i>. We identify distinct adsorption regimes: a single-surface and single-patch adsorbed state for <i>L</i> &gt; <i>L</i>_s, an upper-lower and multi-patch adsorbed state for <i>L</i> &gt; <i>L</i>_m, and a complete adsorbed state for <i>L</i> &gt; <i>L</i>_c. At weak ε_ps, the polymer chain adopts single-surface and single-patch adsorption for middle <i>L</i> and upper-lower and multi-patch adsorption for large <i>L</i>. Conversely, a strong ε_ps promotes upper-lower and multi-patch adsorption for small <i>L</i>, and single-surface and single-patch adsorption as <i>L</i> increases. The adsorption degree increases monotonically to saturate with ε_ps, while &lt;<i>n</i>_p&gt; initially increases and subsequently decays toward stability. Notably, &lt;<i>R</i>²_g,xy&gt; first decreases, then increases, and finally decreases to stabilize as ε_ps increases. These results highlight the role of patch geometry and interaction strength in governing polymer adsorption behavior.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533686","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}

{"title":"Nonlinear Polymerization in an HCSTR, the Age Distribution and the Inhomogeneous Distribution of Branch Points","authors":"Rolf Bachmann,&nbsp;Marcel Klinger","doi":"10.1002/mats.202500064","DOIUrl":"https://doi.org/10.1002/mats.202500064","url":null,"abstract":"<div>\u0000 \u0000 <p>The effect of the broadening of the molecular weight distribution (MWD) in a continuous operation in an HCSTR accompanied by an increased tendency to form gel caused by branching and crosslinking reactions is well known. A more detailed understanding of this phenomenon can be gained from the age distribution. This new concept, introduced here, is a generalization of the residence time distribution and describes the age of individual monomeric units of a polymer chain, which is the time elapsed since the unit entered the reactor as a monomer. It is shown that in living and step growth polymerization the branching density depends on the length of the polymer chain. In living polymerization, it is a linear function of chain length whereas in step growth polymerization it follows a square root function. This leads to high molecular weight tailing and the formation of very inhomogeneous polymer molecules or networks. The onset of gelation is much earlier than in case of an uniform distribution of branch points. The concept of the age distribution is very general and applies to general reaction systems. In a reactor with recycles, the time a chemical species spends in the reactor depends on the reaction path.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533685","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}

{"title":"Determination of the Kinetic Parameters of Multistage Condensed Phase Reactions","authors":"Alireza Aghili,&nbsp;Andrei A. Stolov,&nbsp;Amir Hossein Shabani","doi":"10.1002/mats.202500063","DOIUrl":"https://doi.org/10.1002/mats.202500063","url":null,"abstract":"<div>\u0000 \u0000 <p>The discrete cosine transform (DCT) and Chebyshev series expansion (CSE) have the capability of approximating the functions with zero error at specific points known as nodes. Based on this property, this study introduces an isoconversional analysis method for complex reactions using the DCT or CSE models for the conversion function, applicable to both isothermal and nonisothermal conditions. The new method was applied to the kinetic data from simulated reactions as well as the thermal degradation of the polymer coating of an optical fiber. The results demonstrate that the DCT and CSE facilitate the calculation of kinetic parameters with very high accuracy. Notably, the conversion function and pre-exponential factor of complex multistage reactions, with multiple peaks in reaction rate curves, can be accurately estimated using the new approach. The GNU Octave/MATLAB codes have been made available to readers, enabling them to apply the novel method to their own kinetic data.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533720","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}

{"title":"Brownian Dynamics Investigations of the Scattering Function of Ideal and Excluded Volume Ring Polymers in Higher Dimensions","authors":"Matthew Jura,&nbsp;Khoa Dang Dinh,&nbsp;Marvin Bishop","doi":"10.1002/mats.202500072","DOIUrl":"https://doi.org/10.1002/mats.202500072","url":null,"abstract":"<div>\u0000 \u0000 <p>Brownian dynamics are used to investigate the scattering functions of ideal and excluded volume ring polymers in two to seven spatial dimensions. The scattering functions for ideal and excluded volume polymers examined are in very good agreement with theoretical predictions in all dimensions. As the dimension is increased, the scattering functions for the excluded volume rings converge toward the ideal results, although more slowly than in the case of linear polymers. These findings indicate that excluded volume rings behave more and more as ideal ones as the dimension gets larger, with dimension four being the cross-over point.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533513","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}

{"title":"Coupled Electro-Thermal and Mechanical Simulation of Radio-Frequency Welding of ETPU Bead Foams: A Multiphysics Approach and Its Experimental Validation","authors":"Marcel Dippold,&nbsp;Michael Scheiber,&nbsp;Holger Ruckdäschel","doi":"10.1002/mats.202500075","DOIUrl":"https://doi.org/10.1002/mats.202500075","url":null,"abstract":"<p>Radio-frequency (RF) welding offers a promising, energy-efficient alternative to conventional steam-chest molding (SCM) for processing thermoplastic bead foams. This study presents a coupled electro-thermal and mechanical simulation model to predict the welding behavior and mechanical performance of expanded thermoplastic polyurethane (ETPU) bead foams. The model, implemented in COMSOL Multiphysics, incorporates temperature-dependent dielectric and mechanical properties. The electro-thermal simulation predicts spatial temperature distributions during RF welding and is validated by process-integrated temperature measurements and measured RF-generator power. These local temperatures are used to predict fusion quality at bead interfaces for subsequent mechanical simulation of tensile tests. The predicted stress distribution, crack formation, and failure behavior show good agreement with experimental results obtained via digital image correlation. The model reveals that surface cooling effects limit welding quality and mechanical strength despite sufficient core temperatures. The validated framework enables virtual process optimization and serves as a digital twin for predictive design of RF-welded foam parts. Future studies will extend the approach to other thermoplastic bead foams and integrate improved material models to enhance simulation accuracy.</p>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202500075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533514","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}

{"title":"Hybrid Conjugated Nanostructures of Polythiophene and Carbon Allotropes: Simulation-Based Probing of Structural and Electronic Interplay","authors":"Muhammad Hamza Rasheed,&nbsp;Umer Mehmood,&nbsp;Yasir Qayyum Gill,&nbsp;Muhammad Younas,&nbsp;Syed Ezaz Haider Gillani","doi":"10.1002/mats.202500078","DOIUrl":"https://doi.org/10.1002/mats.202500078","url":null,"abstract":"<div>\u0000 \u0000 <p>The understanding of molecular interactions and charge delocalization mechanisms under polythiophene system environments is essential to improving their catalytic function in energy and electronic capacities. In this study a more holistic computational research approach is used to assess the conformational dynamics and interfacial compatibility of polythiophene with different carbon nanomaterials: graphene, carbon nanotubes (CNTs), fullerene (C60), and carbon nanoparticles. Interaction energies (Eint) and structural conformations were evaluated using quantum mechanical density functional theory (DFT) and reactive force field (ReaxFF) simulations in Materials Studio to further rationalize electronic coupling and charge delocalization. Polythiophene–graphene interface exhibited a highly favorable interaction energy (−205.94 kJ/mol) among those studied, favoring π–π stacking and making charge transfer highly effective, with CNTs being the next most favorable (−39.11 kJ/mol) compared to fullerene (−25.29 kJ/mol) and carbon nanoparticles (−21.97 kJ/mol). These findings offer valuable molecular-level insights for the rational design of polythiophene-based catalytic composites, paving the way for improved performance in photocatalysis, electrocatalysis, and molecular electronics.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533765","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}

{"title":"The Logistic Function in Glass Transition Models of Amorphous Polymers: II. A Theoretical Framework for Isothermal Compression Processes","authors":"Claudio Corbisieri","doi":"10.1002/mats.202500052","DOIUrl":"https://doi.org/10.1002/mats.202500052","url":null,"abstract":"&lt;p&gt;Recently, a methodology to derive an exactly-solvable Riccati equation that approximates the macroscopic-phenomenological behavior of amorphous polymers at glass transition during isobaric cooling was introduced [C. Corbisieri, &lt;i&gt;Macromol. Theory Simul&lt;/i&gt;. 33 (2024): 2400052]. In the present work, this methodology is applied to derive a closed-form expression in terms of mathematical functions that describes the pressure derivative of the specific volume during isothermal compression. For this purpose, a relation between the compression rate and relaxation time at glass transition pressure, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;mi&gt;g&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;annotation&gt;$P_g$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, formally identical to the Frenkel–Kobeko–Reiner equation, is postulated. The closed-form expression contains the logistic function, thus featuring a continuous transition region centered around the temperature and compression-rate dependent glass transition pressure. The resulting constitutive model well-fits the pressure-volume-temperature data of polycarbonate in the equilibrium state, the vitreous state, and at glass transition, collected in the standard isothermal mode in the pressure range &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;P&lt;/mi&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;MPa&lt;/mi&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;to&lt;/mi&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mn&gt;200&lt;/mn&gt;\u0000 &lt;mspace&gt;&lt;/mspace&gt;\u0000 &lt;mi&gt;MPa&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$P=10 ,mathrm{MPa},{rm to}, 200 ,mathrm{MPa}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; at temperatures &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;T&lt;/mi&gt;\u0000 &lt;mn&gt;0&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;mo&gt;=&lt;/mo&gt;\u0000 &lt;msup&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;mn&gt;285&lt;/mn&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mn&gt;265&lt;/mn&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mi&gt;⋯&lt;/mi&gt;\u0000 &lt;mo&gt;,&lt;/mo&gt;\u0000 &lt;mn&gt;65&lt;/mn&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;mo&gt;∘&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;C&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$T_0=leftlbrace 285,265,dots,65rightrbrace mathrm{^{circ }C}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. This work thus confirms the validity of the logistic function in glass transition models of amorphous polymers and establishes a theoretical framework to assess t","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mats.202500052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533669","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}

{"title":"Extensions to Miller Macosko Theory and Validation by Means of Stockmayer's Equation","authors":"Colin Cameron","doi":"10.1002/mats.202500049","DOIUrl":"https://doi.org/10.1002/mats.202500049","url":null,"abstract":"<div>\u0000 \u0000 <p>The recursive method of Miller and Macosko for calculating the average properties of linear and non-linear A + B step-growth polymers is extended to give formulae for the site- and weight-average functionality, and the site-average mass of a polymerising mixture at any extent of conversion of functional groups. These parameters are necessary for the calculation of the weight average molecular weight of polymer systems. All derived formulae are fully validated using the output of Stockmayer's equation, by means of two examples, one branched and one linear step growth polymer, which are then combined in a second stage to show the application of the new expressions to polymeric reactants in the pre-gel state, without the need for analytical expressions for chain length or functionality distributions. This second stage is also validated using Stockmayer's equation. The new formulae apply to any co-reactive chemistries used in step polymerization. In linear A₂ + B₂ step polymerization, processed to less than complete reaction, use of these new recursive relations yields a new, simpler method to identify the abundance of chains with minority A groups at both ends, chains with one A group and one B group, and chains with majority B groups at both ends.</p>\u0000 </div>","PeriodicalId":18157,"journal":{"name":"Macromolecular Theory and Simulations","volume":"34 6","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145533662","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}