Special Issue "Polymer Rheology: Fundamentals and Applications"

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Physics".

Deadline for manuscript submissions: 31 August 2020.

Special Issue Editors

Prof. Valery Kulichikhin
Website
Guest Editor
Russian Academy of Sciences, Moscow, Russia
Interests: polymer physical chemistry; colloid chemistry; rheology; polymer processing; fiber spinning
Special Issues and Collections in MDPI journals
Prof. Alexander Malkin
Website
Guest Editor
Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia
Interests: mechanics of polymers; rheology of polymer melts and solutions; colloid; multicomponent compositions; nanocomposites; polymer technology and pocessing

Special Issue Information

Dear Colleagues,

Traditionally, rheology as a branch of mechanics has been directed towards understanding the interrelationships between stresses, strains, and their rates. The transition to polymer objects has introduced into consideration the presence in materials of long flexible macromolecules, which insert novel features in rheology, interconnected with polymer physics: configurations and conformations of macromolecules, long relaxation times and their spectra, high elastic deformations, memory effects, and so on. A lot of constitutive rheological equations have been developed, which allow for the prediction of basic rheological behavior of polymers. However, the appearance of novel polymers with macromolecules of complex shapes, including stiff-chain configuration; multicomponent compositions, such as polymer solutions and blends; as well as composites and nanocomposites based on polymer matrices, has led to the development of new rheological approaches to describe their behavior correctly.

However, with the onset of “plastic area” and such processing methods as extrusion, injection molding, fibers, and films spinning, a rheological description of polymer melts and solutions has become obligatory for the efficient production of polymer articles. In addition to classical methods of rotational and capillary shear rheology, the uniaxial and biaxial extension, squeezing, and superposition of different kinds of strains has received an additional impulse to development. Much more attention has been devoted to polymer solutions, based on such polymers as cellulose, polyacrylonitrile, and polyvinylalcohole, which have become a source of textile and technical fibers, as well as polylactide, polyglycolide, and other biocompatible and biodegradable fibers and nanofibers for medical applications.

Thus, polymer rheology has a dual meaning in polymer science: fundamental and applied. Both these inputs will be considered in the coming Issue.

Dr. Valery Kulichikhin
Dr. Alex Malkin
Guest Editors

Keywords

  • Rheology of polymer melts and solutions
  • Biocompatible polymers
  • Liquid crystalline polymers
  • Polymer processing
  • Composites and nanocomposites

Published Papers (4 papers)

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Research

Open AccessArticle
Synthesis and Investigation of Thermo-Induced Gelation of Partially Cross-Linked Poly-2-isopropyl-2-oxazoline in Aqueous Media
Polymers 2020, 12(3), 698; https://doi.org/10.3390/polym12030698 - 21 Mar 2020
Abstract
Water-soluble, partially cross-linked poly-2-isopropyl-2-oxazoline combining the properties of chemical and physical gels was synthesized by a two-step procedure. Thermally induced sol-gel transition in its aqueous solution was studied by rheology, light scattering, and turbidimetry. It was demonstrated that the synthesized product is bimodal; [...] Read more.
Water-soluble, partially cross-linked poly-2-isopropyl-2-oxazoline combining the properties of chemical and physical gels was synthesized by a two-step procedure. Thermally induced sol-gel transition in its aqueous solution was studied by rheology, light scattering, and turbidimetry. It was demonstrated that the synthesized product is bimodal; it consists of linear and cross-linked components. The cross-linked components are responsible for the gelation, while the linear ones abate the viscosity growth. Heating the solution above the phase transition temperature leads to the self-assembly of the particles into a physical gel. The combination of chemical and physical cross-linking was found to be a prospective route for thermosensitive gel development. Full article
(This article belongs to the Special Issue Polymer Rheology: Fundamentals and Applications)
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Open AccessArticle
Superharmonic Resonance in Carbon-Black-Filled Rubber by High-Frequency DMA
Polymers 2019, 11(10), 1653; https://doi.org/10.3390/polym11101653 - 11 Oct 2019
Abstract
A systematic study of several SBR compounds filled with carbon black of various grades were analysed with the high-frequency Dynamic Mechanical Analyzer (HF DMA) in order to quantify the degree of nonlinearity induced by fillers in rubber compounds. These filler grades indirectly reflect [...] Read more.
A systematic study of several SBR compounds filled with carbon black of various grades were analysed with the high-frequency Dynamic Mechanical Analyzer (HF DMA) in order to quantify the degree of nonlinearity induced by fillers in rubber compounds. These filler grades indirectly reflect different degrees of microdispersion, which seems to be the main influence on the superharmonic resonance phenomenon observed in HF DMA. This statement arises from the comparison of the microdispersion observed in TEM images. In the second part of the paper, a model compound filled with carbon black is enhanced with a standard reinforcing resin, which leads to a more compact filler network. This induces a higher superharmonic resonance response as well as a higher transmissibility behaviour. Full article
(This article belongs to the Special Issue Polymer Rheology: Fundamentals and Applications)
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Open AccessArticle
Opposite Effects of SiO2 Nanoparticles on the Local α and Larger-Scale α’ Segmental Relaxation Dynamics of PMMA Nanocomposites
Polymers 2019, 11(6), 979; https://doi.org/10.3390/polym11060979 - 03 Jun 2019
Cited by 2
Abstract
The segmental relaxation dynamics of poly(methyl methacrylate)/silica (PMMA/SiO2) nanocomposites with different compositions (ϕSiO2) near and above the glass transition temperature were investigated by mechanical spectroscopy. At ϕSiO2 ≤ 0.5%, the α peak temperature hardly changes [...] Read more.
The segmental relaxation dynamics of poly(methyl methacrylate)/silica (PMMA/SiO2) nanocomposites with different compositions ( ϕ SiO 2 ) near and above the glass transition temperature were investigated by mechanical spectroscopy. At ϕ SiO 2 ≤ 0.5%, the α peak temperature hardly changes with ϕ SiO 2 , but that of α’ relaxation composed of Rouse and sub-Rouse modes decreases by 15 °C due to the increase of free volume. At ϕ SiO 2 ≥ 0.7%, both α and α’ relaxations shift to high temperatures because of the steric hindrance introduced by nanoparticle agglomeration. On the other hand, with increasing ϕ SiO 2 , the peak height for α relaxation increases at ϕ SiO 2 ≤ 0.5% and then decreases at ϕ SiO 2 ≥ 0.7%, but that for α’ relaxation shows an opposite behavior. This is because at low ϕ SiO 2 , the short-chain segments related to α relaxation can easily bypass the particles, but the longer-chain segments related to α’ relaxation cannot. At high ϕ SiO 2 , the polymer chains were bound to the nanoparticles due to the physical adsorption effect, leading to the decrease of relaxation unit concentration involved in α relaxation. However, the dissociation of those bonds with heating and the concentration heterogeneity of polymer chains result in the increase of peak height for α’ relaxation. Full article
(This article belongs to the Special Issue Polymer Rheology: Fundamentals and Applications)
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Open AccessArticle
Improving the Thermal Stability of Hydrophobic Associative Polymer Aqueous Solution Using a “Triple-Protection” Strategy
Polymers 2019, 11(6), 949; https://doi.org/10.3390/polym11060949 - 01 Jun 2019
Cited by 1
Abstract
Because of their high viscoelasticity, Hydrophobic Associative Water-Soluble Polymers (HAWSPs) have been widely used in many industrial fields, especially in oilfield flooding and fracturing. However, one major problem which limits the wide applications of HAWSPs is their weak resistance to high temperatures. Once [...] Read more.
Because of their high viscoelasticity, Hydrophobic Associative Water-Soluble Polymers (HAWSPs) have been widely used in many industrial fields, especially in oilfield flooding and fracturing. However, one major problem which limits the wide applications of HAWSPs is their weak resistance to high temperatures. Once the temperature increases over 100 °C, the viscosity of the fracturing fluid decreases rapidly, because high temperatures reduce fluid viscosity by oxidizing the polyacrylamide chains and weakening the association of hydrophobic groups. To improve the high temperature resistance of one HAWSP, a triple-protection strategy was developed. First, rigid N-vinyl-2-pyrrolidone moiety was introduced into the polymer chains. Second, an environmentally-friendly deoxidizer, carbohydrazide, was selected to prevent polymer oxidization by scavenging dissolved oxygen. Results showed that both the rigid groups and the deoxidizer improved the temperature resistance of the polymer and helped it maintain high viscosity under high temperature and shear rate. Using these two protection strategies, the resistant temperature of the polymer could reach 160 °C. However, the polymer network still got severely damaged at further elevated temperatures. Therefore, as the third protection strategy, the pre-added high temperature responsive crosslinking agent was applied to form new networks at elevated temperatures. The results have shown that the optimized polymer solution as a kind of fracturing fluid showed good temperature resistance up to 200 °C. Full article
(This article belongs to the Special Issue Polymer Rheology: Fundamentals and Applications)
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