Article
Polymer Science
Hiroshi Watanabe, Yumi Matsumiya, Takeshi Sato
Summary: This study investigated the effects of changes in local elastic strength, segmental friction coefficient, and Brownian force intensity of polymer chains under fast flow on rheological and structural properties of the Rouse model. Analytical expressions of nonlinear rheological properties and end-to-end stretch ratio were derived using the Rouse model's Langevin equation with decoupling and preaveraging approximations, allowing for a preliminary test of Brownian force behavior. The study also raised questions about common assumptions in molecular models regarding the relationships between Brownian force, segmental friction coefficient, and flow conditions.
Article
Mechanics
Simon J. Haward, Stylianos Varchanis, Gareth H. McKinley, Manuel A. Alves, Amy Q. Shen
Summary: Part I presents a microfluidic device for generating near-homogeneous uniaxial and biaxial elongational flows. In Part II, this device is used to examine the extensional rheology of dilute polymer solutions compared to measurements made under planar extension. The extension rate and tensile stress difference generated in the fluid are measured using micro-particle image velocimetry and excess pressure drop measurements. The results show that at higher polymer concentrations, the experimental measurements deviate from the model predictions due to intermolecular interactions as the polymer chains unravel in the extensional flows.
JOURNAL OF RHEOLOGY
(2023)
Article
Mechanics
Sourabh Dhawan, Malay Kumar Das, Pradipta Kumar Panigrahi
Summary: The research investigates the effectiveness of geometric modification in stabilizing viscoelastic fluid flow through a planar channel. The square cylinder positioned in front of the contraction plane pre-deforms the fluid, causing significant changes in flow characteristics. The study demonstrates that pre-deformation of the fluid stabilizes flow in a specific range and reduces the size of corner vortex in another range. Furthermore, an increase in a certain parameter initiates elastic turbulence in the flow.
Article
Physics, Fluids & Plasmas
Kenji Nishizawa, Natsuki Honda, Shono Inokuchi, Hiroyuki Ebata, Takayuki Ariga, Daisuke Mizuno
Summary: In this study, the fluctuating dynamics of colloidal particles in weakly crosslinked F-actin networks were investigated using optical-trap-based microrheology. The statistics of jump dynamics were analyzed, revealing how heterogeneous relaxations observed in equilibrium systems became homogeneous under constant forcing beyond the linear regime.
Article
Polymer Science
Qi Zhang, Lidan Lan, Zhuo Zheng, Pengfei Liu, Hong Wu, Shaoyun Guo, Congmei Lin, Guansong He
Summary: In this study, a designed intense stretching process was used to construct a highly oriented and condensed shish-kebab crystalline structure, which improved the mechanical properties and in-plane thermal conductivity of the HDPE/UHMWPE blends. By introducing disentangled UHMWPE chains and utilizing multistage stretching extrusion and uniaxial stretching, the tensile strength, Young's modulus, and in-plane thermal conductivity of the blends were significantly increased. This research provides a new perspective on the application of high-performance polyethylene blends.
Article
Engineering, Chemical
Stephen Barilovits, Saad A. Khan, Eunkyoung Shim
Summary: This study experimentally investigated the fiber and web formation process of an array of annular meltblown spinnerets. It was found that smaller fibers in cooler air streams require shorter die-collector distances to form bonded fabrics, and the polymer spinning temperature is largely determined by air temperature. The study also showed that processing conditions related to fiber diameter distribution, with median diameters ranging from less than 1 μm to almost 14 μm.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Chemistry, Physical
Qianhui Wu, Jijiang Ge
Summary: Nanoparticle strengthened polymer gels have been shown to improve the uniformity of gel network structure and inhibit polymer degradation, resulting in higher strength and thermal stability. The addition of nanoparticles also increases the hydrophilicity of the polymer gel. The enhanced gel exhibits nonlinear viscoelastic behavior with good ductility and toughness, as well as a high yield stress for better blocking capacity in field applications.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Polymer Science
Zhanpo Han, Jixiao Hao, Cong Du, Hao Yan, Hua Yuan, Kaiwen Li, Lidan Wang, Zhen Xu, Yeqiang Tan
Summary: The current environment crisis has led to the rapid expansion of degradable biomass polymers as a replacement for petrochemical polymers. In this study, we developed a series of high-performance alginate fibers using a new entanglement-enhanced stretching strategy and examined its mechanism. The fibers exhibited high modulus and superior tensile strength, outperforming most regenerated biomass fibers.
Article
Polymer Science
Yanan Gong, Wenlin Zhang, Ronald G. Larson
Summary: In atomistic molecular dynamics simulations, it is found that alkane oligomers form an oriented interface when in contact with a crystal slab of stretched periodic polyethylene chains, which serves as a nucleation site for crystal growth.
Article
Engineering, Multidisciplinary
Serife Akkoyun, Nuray Oktem
Summary: This study investigates the uniaxial elongational flow of a polymer solution in the electrospinning process through numerical and experimental research, demonstrating the predictive ability of the simulations. Emphasis is placed on determining the effects of fiber diameter and initial polymer concentration, as well as examining the impact of different concentration regimes on thinning dynamics.
ENGINEERING SCIENCE AND TECHNOLOGY-AN INTERNATIONAL JOURNAL-JESTECH
(2021)
Review
Polymer Science
Yumi Matsumiya, Hiroshi Watanabe
Summary: The rheological behavior of polymeric liquids was traditionally believed to be universally determined by a few time-independent molecular parameters, but recent studies have shown non-universality under extensional flow conditions. A key concept is the reduction of segmental friction of highly oriented/stretched polymer chains, which changes with the chemical structure of the polymer and solvent as well as the polymer concentration.
PROGRESS IN POLYMER SCIENCE
(2021)
Article
Mechanics
Karen Y. Perez-Salas, Gabriel Ascanio, Leopoldo Ruiz-Huerta, Juan P. Aguayo
Summary: An analytical approximation for the flow of a linear Phan-Thien-Tanner model fluid through an axisymmetric semi-hyperbolic contraction is presented in this study. The semi-analytical solution proposed can accurately represent the exponential version of the viscoelastic model. The flow model equations for both linear and exponential Phan-Thien-Tanner models are solved with the consideration of Navier boundary conditions to account for slip at the geometry wall.
Article
Engineering, Manufacturing
Ana Luiza Lima, Felipe Q. Pires, Leandro Augusto Hilgert, Livia L. Sa-Barreto, Tais Gratieri, Guilherme M. Gelfuso, Marcilio Cunha-Filho
Summary: This study designed a short and sensitive protocol based on rheology and mechanical evaluation to assess the viscoelastic behavior of hot-melt extrusion filaments and predict their impact on 3D medicines. The results showed that an adequate plasticizer concentration could produce filaments suitable for printing.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Polymer Science
Amulya K. Pervaje, Melissa A. Pasquinelli, Saad A. Khan, Erik E. Santiso
Summary: In this paper, a multiscale approach is presented to predict the mechanical properties of polypropylene fibers based on chemical and physical characteristics. The method relies on validation with experimental data and utilizes molecular simulations and neural network models to predict parameters for a chosen constitutive model.
Article
Polymer Science
Jianshe Xia, Julia Ann Kalow, Monica Olvera de la Cruz
Summary: This study investigates the topological structural changes, microscopic dynamics, and linear rheology of unentangled vitrimers through molecular dynamics simulations. The results show minor variations in topological structure with temperature and increased dynamic heterogeneities near the topological freezing transition temperature. The simulation results are quantitatively consistent with predictions from the sticky Rouse model.
Article
Mechanics
Ricardo J. E. Andrade, Alan R. Jacob, Francisco J. Galindo-Rosales, Laura Campo-Deano, Qian Huang, Ole Hassager, George Petekidis
JOURNAL OF RHEOLOGY
(2020)
Article
Polymer Science
Wendi Wang, Jeppe Madsen, Natalja Genina, Ole Hassager, Anne L. Skov, Qian Huang
Summary: This study introduces a new strategy to enhance the flowability, extensibility, and strain hardening of ionomers by studying diamine-neutralized entangled polymers. The neutralized ionomers showed relaxation processes similar to entangled polymers with faster terminal relaxation, indicating potential for improved processing. Good extensibility and strain hardening were achieved through ionic sticker reassociation and entanglements.
Article
Mechanics
Manfred H. Wagner, Esmaeil Narimissa, Qian Huang
Summary: The study extends the criterion for brittle fracture of entangled polymer liquids by considering the effects of finite chain extensibility and polymer concentration. Experimental data and models support the finding that crack initiation originates from the rupture of C-C bonds, leading to the fracture of polymer chains and crack propagation.
JOURNAL OF RHEOLOGY
(2021)
Article
Mechanics
Daniele Parisi, Maria Kaliva, Salvatore Costanzo, Qian Huang, Pierre J. Lutz, Junyoung Ahn, Taihyun Chang, Michael Rubinstein, Dimitris Vlassopoulos
Summary: This study provides a comprehensive experimental investigation of the rheological properties of purified entangled ring polystyrenes and their blends with linear chains in nonlinear shear and elongation. It reveals subtle differences in shear-rate dependence between rings and linear polymers or their blends, and emphasizes the significant role of rings in enhancing viscosity in elongation.
JOURNAL OF RHEOLOGY
(2021)
Article
Polymer Science
David Boucher, Jeppe Madsen, Liyun Yu, Qian Huang, Nicolas Causse, Nadine Pebere, Vincent Ladmiral, Claire Negrell
Summary: Vitrimer materials, permanently crosslinked but reshapable polymers, are of growing interest for their potential in recycling and sustainable development. This study presents the development of a polystyrene-based vitrimer utilizing the hemiacetal ester exchange reaction of carboxylic acid for potential impact on plastic consumption.
Article
Polymer Science
Qian Huang
Summary: This article provides a perspective on recent findings in extensional rheology for polymer melts and solutions with different macromolecular architectures. It focuses on the argument of flow-induced friction reduction for linear polymer systems, understanding how to control extensional viscosity for branched polymers, and summarizes recent progress in extensional rheology for ring polymers. The article emphasizes the importance of more data from both experiments and simulations for improving the fundamental understanding and development of theories in molecular design of polymer materials.
Article
Physics, Multidisciplinary
Kell Mortensen, Anine L. Borger, Jacob J. K. Kirkensgaard, Qian Huang, Ole Hassager, Kristoffer Almdal
Summary: This study presents a detailed description of the structural relaxation of a polystyrene star polymer after cessation of high-rate extensional flow, which includes three distinct regimes of relaxation and ends with relaxation via reptation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Mechanics
Ole Hassager, Yanwei Wang, Qian Huang
Summary: Polymeric liquid bridges are prone to failure during extension, but a steady extensional viscosity can still be measured under specific conditions. Additionally, reliable stress measurements can be obtained during a relaxation phase. Various constitutive equations were simulated to draw these conclusions.
Article
Mechanics
Yiming Zhong, Liyun Yu, Qian Huang
Summary: This work investigates the relationship between the linear viscoelastic behavior and the nonlinear behavior in fast extensional flow at short length scales. The linear viscoelasticity of polystyrene (PS) melts and solutions was measured in the transition to glassy regime, and it was found that the third crossover points of G' and G'' plots occurred at the same frequency for samples compared at the same temperature. The steady-state extensional viscosity in fast extensional flow seems to depend on the number of Kuhn segments per chain, rather than the PS fraction.
Article
Polymer Science
Qian Huang, Ole Hassager, Jeppe Madsen
Summary: This article demonstrates the three-dimensional mapping of chain scission events following induced fracture in bulk polymer specimens. By adding a profluorescent perylene diimide-based dye and a reference dye to the matrix, a ratiometric determination of relative radical concentration is achieved.
Article
Polymer Science
Shuang Liu, Jiaqi Zhang, Lian R. Hutchings, Li Peng, Xianbo Huang, Qian Huang
Summary: This study investigates the effects of short arms on the linear and nonlinear shear rheological behavior of model asymmetric 3-arm star polymers. It is found that increasing the length of the short arm decreases the linear viscoelastic rubber plateau, indicating a solvent effect that dilutes the star polymers. This idea is supported by the relationship between the plateau moduli of polymer solutions GN(& phi;) and the corresponding polymer melts GN(1) for entangled linear polymers.
Article
Mechanics
Chen Liu, Jianzhong Lin, Zhenyu Ouyang
Summary: This study simulated the locomotion state and motion type of elliptical squirmers in a channel flow of power-law fluids. The influence of different parameters on the squirmers was explored, and it was found that coupled structures are prone to break and viscosity significantly affects the flow velocity and motion type of squirmers.
Article
Mechanics
E. E. Herrera-Valencia, M. L. Sanchez-Villavicencio, C. Soriano-Correa, O. Bautista, L. A. Ramirez-Torres, V. J. Hernandez-Abad, F. Calderas
Summary: This study investigated the electroosmotic flow of a viscoelastic fluid in a capillary system. The rheology of the fluid was characterized by a novel generalized exponential model equation, and the effect of charge density on the double-layer field and electrical forces was analyzed. Mathematical models were used to describe the rheological properties and flow performance of the fluid, and experimental data were used to make predictions. The study also examined the influence of applied forces on the structure of the fluid.
Article
Mechanics
Stefano Amadori, Giuseppe Catania
Summary: This article presents a multi-step, iterative technique for locally non-parametric identification of the standard linear solid (SLS) material model using fractional order time differential operators. Test input data consists of a set of identified material complex modulus values estimated at different frequency values obtained from input-output experimental measurements and quasi-static relaxation measurements on the same specimen. The proposed technique is based on an algebraic procedure to solve an overdetermined system of linear equations in order to obtain optimal values for the unknown parameters of the model. The procedure is non-parametric, as the order of the SLS model is initially unknown.
