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Polymers
Special Issues
Physical Aging of Polymers
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Physical Aging of Polymers

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

Deadline for manuscript submissions: closed (15 February 2023) | Viewed by 4033

Special Issue Editor

Prof. Dr. Magdalena Stepczyńska

E-Mail Website
Guest Editor
Institute of Materials Science, Department of Materials Engineering, Kazimierz Wielki University, Bydgoszcz, Poland
Interests: biodegradable materials; the development of biobased polymers; composites and biocomposites; the modification of natural polymers; natural plant compounds; natural biocidal compounds; natural fibers and their modification; physical and chemical modification of polymers; sterilization; biodegradation; environmental protection; corona discharges and plasma modification; polymers for packaging and pharmaceutical industries, biotechnology, and horticulture (mostly for manufacture of packaging for food, drugs, and medical instruments)
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Physical aging, as applied to polymers, encompasses a very wide range of behaviors, all of which are linked by the same phenomenon. This phenomenon is the observed change in a property of the polymer as a function of storage time, at constant temperature, at zero stress, and under no influence from any other external conditions. In experimental studies of physical aging, the equilibrium state (volume or enthalpy) is not often known, except by extrapolation from measured values at higher temperatures, whereas in engineering applications, physical aging will commonly occur throughout the service lifetime of the materials.

Physical aging is a ubiquitous phenomenon in amorphous polymers that originates from the fact that they are generally out-of-equilibrium. It should be stressed here that aging is not confined to amorphous polymers, nor is it initiated only by temperature changes.

Aging can significantly influence the thermomechanical properties and subsequently the macroscopic response of polymers. It involves reversible changes in properties with no permanent modification to the structure, either chemical or physical, of the material.

The aim of this Special Issue is to highlight progress in the field of physical aging in polymers, including biodegradable polymers and polymer nanocomposites. This Special Issue covers all aspects concerning the use of methods to monitor the physical aging of polymers, the fate of the dynamics and thermodynamics of polymers, and the modification of the rate of physical aging of polymers.

This Special Issue covers the influence of physical aging on some mechanical properties, in particular with reference to the extent to which the changes in mechanical properties on aging may be interpreted quantitatively in light of the structural changes characterized by volume and enthalpy relaxation.

Prof. Dr. Magdalena Stepczyńska
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • physical aging
  • polymer
  • amorphous polymers
  • biodegradable polymers
  • nanocomposites
  • thermodynamics of polymers
  • the rate of aging
  • thermomechanical properties
  • structural changes
  • enthalpy

Published Papers (2 papers)

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13 pages, 1656 KiB  
Article
Evolution of the Viscoelastic Properties of Filler Reinforced Rubber under Physical Aging at Room Temperature
by María Vizcaíno-Vergara, Leif Kari, Lewis B. Tunnicliffe and James J. C. Busfield
Polymers 2023, 15(7), 1806; https://doi.org/10.3390/polym15071806 - 6 Apr 2023
Viewed by 1420
Abstract
Filler reinforced rubber is widely used for engineering applications; therefore, a sound characterization of the effects of physical aging is crucial for accurately predicting its viscoelastic properties within its operational temperature range. Here, the torsion pendulum is used to monitor the evolution of [...] Read more.
Filler reinforced rubber is widely used for engineering applications; therefore, a sound characterization of the effects of physical aging is crucial for accurately predicting its viscoelastic properties within its operational temperature range. Here, the torsion pendulum is used to monitor the evolution of the storage and loss modulus of carbon black filled samples for four days after a temperature drop to 30 °C. The storage modulus presents a continuous increase, while the loss modulus generally displays a steady decrease throughout the four days that each test was conducted. The relationship of the recovery rates with the carbon black properties is also studied, analysing its dependency on the particle size and aggregate structure. The evolution of the recovery rate seems to depend linearly on the surface area while the carbon black structure appears to have a much weaker influence on the physical aging behavior for the set of compounds tested. The obtained results corroborate the presence of physical aging at room temperature for filler rubber materials and the ability of the torsion pendulum to monitor the storage and loss modulus change, providing pivotal data on the influence of physical aging on the viscoelastic properties of the material. Full article
(This article belongs to the Special Issue Physical Aging of Polymers)
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13 pages, 1463 KiB  
Article
Synthesis of New Norfloxacin–Tin Complexes to Mitigate the Effect of Ultraviolet-Visible Irradiation in Polyvinyl Chloride Films
by Marwa Fadhil, Emad Yousif, Dina S. Ahmed, Alaa Mohammed, Hassan Hashim, Ahmed Ahmed, Benson M. Kariuki and Gamal A. El-Hiti
Polymers 2022, 14(14), 2812; https://doi.org/10.3390/polym14142812 - 10 Jul 2022
Cited by 8 | Viewed by 1580
Abstract
Polyvinyl chloride is used in the manufacturing of a wide range of products, but it is susceptible to degradation if exposed to high temperatures and sunlight. There is therefore a need to continuously explore the design, synthesis, and application of new and improved [...] Read more.
Polyvinyl chloride is used in the manufacturing of a wide range of products, but it is susceptible to degradation if exposed to high temperatures and sunlight. There is therefore a need to continuously explore the design, synthesis, and application of new and improved additives to reduce the photodegradation of polyvinyl chloride in harsh environments and for outdoor applications. This research investigates the use of new norfloxacin–tin complexes as additives to inhibit the photodegradation of polyvinyl chloride to make it last longer. Reactions between norfloxacin and substituted tin chlorides, in different molar ratios and in methanol under reflux conditions, gave the corresponding organotin complexes in high yields. The chemical structures of the synthesized complexes were established, and their effect on the photodegradation of polyvinyl chloride due to ultraviolet-visible irradiation was investigated. Norfloxacin–tin complexes were added to polyvinyl chloride at very low concentrations and homogenous thin films were made. The films were irradiated for a period of up to 300 h, and the damage that occurred was assessed using infrared spectroscopy, polymeric materials weight loss, depression in molecular weight, and surface inspection. The degree of photodegradation in the polymeric materials was much less in the blends containing norfloxacin–tin complexes compared to the case where no additives were used. The use of the additives leads to a reduction in photodegradation (e.g., a reduction in the formation of short-chain polymeric fragments, weight loss, average molecular weight depletion, and roughness factor) of irradiated polyvinyl chloride. The norfloxacin–tin complexes contain aromatic moieties (aryl and heterocycle), heteroatoms (nitrogen, oxygen, and fluorine), and an acidic center (tin atom). Therefore, they act as efficient photostabilizers by absorbing the ultraviolet radiation and scavenging hydrogen chloride, peroxides, and radical species, thereby slowing the photodegradation of polyvinyl chloride. Full article
(This article belongs to the Special Issue Physical Aging of Polymers)
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