Thermal Characterization of Polymers and Polymer Composites

A topical collection in Polymers (ISSN 2073-4360). This collection belongs to the section "Polymer Analysis and Characterization".

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Editor

Innovation Engineering Department, University of Salento, 73100 Lecce, Italy
Interests: cold-cured adhesives and matrices for FRP employed in constructions; polymeric nanostructured adhesives and coatings; hydrophobic coatings for stone conservation and wood protection; durability of polymers, adhesives and coatings; eco-efficient materials for construction and cultural heritage
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Topical Collection Information

Dear Colleagues,

Thermal analyses (TA) are a set of analytical techniques able to measure and analyze the properties, or their changes, of (synthetic/biobased) polymers, polymeric composites, and of other materials containing a polymeric phase as a function of the temperature (or time) when the material under investigation is subjected to a controlled temperature program.

In the field of polymer science, TA represent an extraordinary useful tool to characterize polymeric materials in a simple and fast way and to investigate a wide variety of their properties during thermal events. It is possible to relate these latter properties to the compositional modifications (polymer blends, presence of fillers, additives, plasticizers, etc.) and to the conditions used for their processing, gaining invaluable information for their production, usage, durability, recycling, and degradation.

Different thermal analysis methods are available for several examination purposes. Among the most commonly employed TA for polymer characterization, there is differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), thermal mechanical analysis (TMA), and dielectric analysis (DEA).

The described techniques, frequently available in most industrial and research laboratories, also have strong potential and wide versatile applications in emerging fields of polymer research, such as polymer-based nanocomposites, polymers for energy applications, biodegradation of polymers, and high-performance polymer composites.

With TA techniques, it is possible to analyze chemical and physical processes related to thermal effects, including glass transition, melting, crystallization, curing reactions, physical aging, evaporation and decomposition processes, stability, interactions with environmental agents, fire retardancy, viscoelastic effects, volumetric and geometrical modifications, and changes in mechanical properties. Modeling and simulation of complex phenomena can be accomplished on the basis of TA data.

This Topical Collection focuses on the thermal analysis and characterization of polymers and polymer composites, on the information that these techniques can provide for optimal production/use/disposal of such materials, and on novel testing methods proposed to highlight properties and features of traditional as well as innovative polymer materials.

Prof. Dr. Mariaenrica Frigione
Collection Editor

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Keywords

  • calorimetry
  • differential scanning calorimetry
  • differential thermal analysis
  • dynamic mechanical thermal analysis
  • modeling
  • thermal analysis
  • thermal characterization
  • thermal events
  • thermal-mechanical analysis
  • thermogravimetric analysis

Published Papers (5 papers)

2024

Jump to: 2023, 2021

20 pages, 6535 KiB  
Article
A Study of the Friction Characteristics of Rubber Thermo-Mechanical Coupling
by Junyu Liu, Meng Wang and Haishan Yin
Polymers 2024, 16(5), 596; https://doi.org/10.3390/polym16050596 - 21 Feb 2024
Viewed by 567
Abstract
The friction performance of tread rubber is related to the safety of the vehicle during driving, especially in terms of shifting speeds, cornering, and changing environmental factors. The experimental design used in this paper employed a self-developed automatic multi-working-condition friction tester to investigate [...] Read more.
The friction performance of tread rubber is related to the safety of the vehicle during driving, especially in terms of shifting speeds, cornering, and changing environmental factors. The experimental design used in this paper employed a self-developed automatic multi-working-condition friction tester to investigate the correlation between the friction coefficient of three tread formulations and various factors, including speed, pressure, temperature, side deflection angle, and lateral camber. This experimental study demonstrates that the coefficient of friction decreases with increasing load and increases with increasing sliding velocities due to changes in adhesion friction. Due to the increasing and decreasing changes in rubber adhesion and hysteresis friction caused by temperature, the coefficient of friction shows a tendency to increase and then decrease with the increase in temperature; thus, temperature has an important effect on the coefficient of friction. Based on the basic theory of friction and experimental research, the Dorsch friction model was modified in terms of temperature, and the analytical relationship between the rubber friction coefficient and the combined variables of contact pressure, slip velocity, and temperature was established, which is more in line with the actual situation of rubber friction. The model predictions were compared with the experimental results, and the error accuracy was controlled within 5%. This verifies the accuracy of the model and provides a theoretical basis for the study of rubber friction. Full article
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12 pages, 2179 KiB  
Article
Machine Learning Backpropagation Prediction and Analysis of the Thermal Degradation of Poly (Vinyl Alcohol)
by Abdulrazak Jinadu Otaru, Zaid Abdulhamid Alhulaybi and Ibrahim Dubdub
Polymers 2024, 16(3), 437; https://doi.org/10.3390/polym16030437 - 05 Feb 2024
Viewed by 1219
Abstract
Thermogravimetric analysis (TGA) is crucial for describing polymer materials’ thermal behavior as a result of temperature changes. While available TGA data substantiated in the literature significantly focus attention on TGA performed at higher heating rates, this study focuses on the machine learning backpropagation [...] Read more.
Thermogravimetric analysis (TGA) is crucial for describing polymer materials’ thermal behavior as a result of temperature changes. While available TGA data substantiated in the literature significantly focus attention on TGA performed at higher heating rates, this study focuses on the machine learning backpropagation analysis of the thermal degradation of poly (vinyl alcohol), or PVA, at low heating rates, typically 2, 5 and 10 K/min, at temperatures between 25 and 600 °C. Initial TGA analysis showed that a consistent increase in heating rate resulted in an increase in degradation temperature as the resulting thermograms shifted toward a temperature maxima. At degradation temperatures between 205 and 405 °C, significant depths in the characterization of weight losses were reached, which may be attributed to the decomposition and loss of material content. Artificial neural network backpropagation of machine learning algorithms were used for developing mathematical descriptions of the percentage weight loss (output) by these PVA materials as a function of the heating rate (input 1) and degradation temperature (input 2) used in TGA analysis. For all low heating rates, modelling predictions were observably correlated with experiments with a 99.2% correlation coefficient and were used to interpolate TGA data at 3.5 and 7.5 K/min, indicating trends strongly supported by experimental TGA data as well as literature research. Thus, this approach could provide a useful tool for predicting the thermograms of PVA materials at low heating rates and contribute to the development of more advanced PVA/polymer materials for home and industrial applications. Full article
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2023

Jump to: 2024, 2021

12 pages, 3525 KiB  
Article
Kinetics and Mechanism of Liquid-State Polymerization of 2,4-Hexadiyne-1,6-diyl bis-(p-toluenesulfonate) as Studied by Thermal Analysis
by Andrey Galukhin, Alexander Kachmarzhik, Alexander Rodionov, Georgy Mamin, Marat Gafurov and Sergey Vyazovkin
Polymers 2024, 16(1), 7; https://doi.org/10.3390/polym16010007 - 19 Dec 2023
Viewed by 635
Abstract
A detailed investigation of the liquid-state polymerization of diacetylenes by calorimetric (DSC) and spectroscopic (in situ EPR) thermal analysis techniques is performed. Isoconversional kinetic analysis of the calorimetric data reveals that liquid-state polymerization is governed by a well-defined rate-limiting step as evidenced by [...] Read more.
A detailed investigation of the liquid-state polymerization of diacetylenes by calorimetric (DSC) and spectroscopic (in situ EPR) thermal analysis techniques is performed. Isoconversional kinetic analysis of the calorimetric data reveals that liquid-state polymerization is governed by a well-defined rate-limiting step as evidenced by a nearly constant isoconversional activation energy. By comparison, solid-state polymerization demonstrates isoconversional activation energy that varies widely, signifying multistep kinetics behavior. Unlike the solid-state reaction that demonstrates an autocatalytic behavior, liquid-state polymerization follows a rather unusual zero-order reaction model as established by both DSC and EPR data. Both techniques have also determined strikingly similar Arrhenius parameters for liquid-state polymerization. Relative to the solid-state process, liquid-state polymerization results in quantitative elimination of the p-toluenesulfonate group and the formation of p-toluenesulfonic acid and a polymeric product of markedly different chemical and phase composition. Full article
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2021

Jump to: 2024, 2023

20 pages, 3550 KiB  
Article
Influence of Carbon Black and Silica Fillers with Different Concentrations on Dielectric Relaxation in Nitrile Butadiene Rubber Investigated by Impedance Spectroscopy
by Gyung-Hyun Kim, Young-Il Moon, Jae-Kap Jung, Myung-Chan Choi and Jong-Woo Bae
Polymers 2022, 14(1), 155; https://doi.org/10.3390/polym14010155 - 31 Dec 2021
Cited by 6 | Viewed by 2236
Abstract
In neat nitrile butadiene rubber (NBR), three relaxation processes were identified by impedance spectroscopy: α and α′ processes and the conduction contribution. We investigated the effects of different carbon black (CB) and silica fillers with varying filler content on the dielectric relaxations in [...] Read more.
In neat nitrile butadiene rubber (NBR), three relaxation processes were identified by impedance spectroscopy: α and α′ processes and the conduction contribution. We investigated the effects of different carbon black (CB) and silica fillers with varying filler content on the dielectric relaxations in NBR by employing a modified dispersion analysis program that deconvolutes the corresponding processes. The central frequency for the α′ process with increasing high abrasion furnace (HAF) CB filler was gradually upshifted at room temperature, while the addition of silica led to a gradual downshift of the center frequency. The activation energy behavior for the α′ process was different from that for the central frequency. The use of HAF CB led to a rapid increase in DC conductivity, resulting from percolation. The activation energy for the DC conductivity of NBRs with HAF CB decreased with increasing filler, which is consistent with that reported in different groups. Full article
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19 pages, 5538 KiB  
Article
Analysis of Acrylic and Methacrylic Networks through Pyrolysis-GC/MS
by Zakaria Belbakra, Alessandro Napoli, Zoubair Cherkaoui and Xavier Allonas
Polymers 2021, 13(24), 4349; https://doi.org/10.3390/polym13244349 - 12 Dec 2021
Cited by 1 | Viewed by 2992
Abstract
A direct analytical method developed to characterize UV-cured networks based on multi-step pyrolysis-gas chromatography-mass spectroscopy (GC/MS) is presented. Application of the method to characterize (meth)acrylate-based UV-cured networks is discussed. The reversion process of methacrylates is clearly observed during pyrolysis. In contrast, the decomposition [...] Read more.
A direct analytical method developed to characterize UV-cured networks based on multi-step pyrolysis-gas chromatography-mass spectroscopy (GC/MS) is presented. Application of the method to characterize (meth)acrylate-based UV-cured networks is discussed. The reversion process of methacrylates is clearly observed during pyrolysis. In contrast, the decomposition of acrylates in high molecular weight degradation products is hardly detected. The potential impact of this technique to elucidate the structural and compositional nature of UV-cured polymeric networks is highlighted. Full article
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