Advances in Rubbers

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

Deadline for manuscript submissions: closed (29 February 2024) | Viewed by 11315

Special Issue Editors

1. School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Sanderson Building, King’s Buildings, Edinburgh EH9 3FB, Scotland, UK
2. LM Wind Power, Kolding, Denmark
Interests: block co-polymers; mechanical properties; fracture mechanisms; tensile properties; electrical properties; epoxy; nanocomposites; rubber
Rubber Technology Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
Interests: elastomer; silicone rubber; short fibre and nanofiller; adhesive; mechanical properties; graphene based elastomeric nanocomposites

Special Issue Information

Dear Colleagues,

Rubber is an important development field of modern new materials. High performance rubber, obtained by various modification methods, is used in the field of electronic information and biomedicine engineering, aerospace, and other important fields.

It is with great pleasure that we invite you to submit a manuscript related to rubber for this Special Issue, which includes papers related—but not limited—to synthesis, modification, process engineering, aging, recycling, etc. Remarkable contributions including research articles, communications, and reviews from experts all over the world are welcome.

Dr. Ankur Bajpai
Prof. Dr. Kinsuk Naskar
Guest Editors

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

  • block co-polymers
  • mechanical properties
  • fracture mechanisms
  • tensile properties
  • electrical properties
  • epoxy
  • nanocomposites
  • rubber
  • elastomer
  • silicone rubber
  • short fibre and nanofiller
  • adhesive
  • mechanical properties

Published Papers (7 papers)

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Research

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15 pages, 2813 KiB  
Article
Enhancing Devulcanizing Degree and Efficiency of Reclaimed Rubber by Using Alcoholic Amines as the Devulcanizing Agent in Low-Temperature Mechano–Chemical Process
by Lei Guo, Lichen Bai, Jinyang Zhao, Kexin Liu, Xingao Jian, Hailin Chai, Fumin Liu, Shouyun Guo, Gongxu Liu and Haichao Liu
Polymers 2024, 16(3), 395; https://doi.org/10.3390/polym16030395 - 31 Jan 2024
Viewed by 537
Abstract
Low-temperature mechanical chemical devulcanization is a process that can produce reclaimed rubber with exceptional mechanical properties. However, the inadequacy and low efficiency of the devulcanization have significantly restricted its application. To address the issues, alcoholic amines, including hydroxyethyl ethylenediamine (AEEA), ethanolamine (ETA), and [...] Read more.
Low-temperature mechanical chemical devulcanization is a process that can produce reclaimed rubber with exceptional mechanical properties. However, the inadequacy and low efficiency of the devulcanization have significantly restricted its application. To address the issues, alcoholic amines, including hydroxyethyl ethylenediamine (AEEA), ethanolamine (ETA), and diethanol amine (DEA), are utilized as devulcanizing agents to promote the devulcanization process. Careful characterizations are conducted to reveal the devulcanizing mechanism and to depict the performances of reclaimed rubbers. Results show that the amine groups in the devulcanizing agents can react with sulfur after the crosslink bonds are broken by mechanical shear force, thus blocking the activity of sulfur and introducing hydroxyl groups into the rubber chains. The incorporation of alcoholic amines can enhance the devulcanizing degree and devulcanizing efficiency, reduce the Mooney viscosity, and improve the mechanical and anti-aging performance. When using DEA as the devulcanizing agent, the sol content of reclaimed rubber increases from 13.1% to 22.4%, the devulcanization ratio increases from 82.1% to 89.0%, the Mooney viscosity decreases from 135.5 to 83.6, the tensile strength improves from 14.7 MPa to 16.3 MPa, the retention rate of tensile strength raises from 55.2% to 82.6% after aging for 72 h, while the devulcanization time is shortened from 21 min to 9.5 min, compared with that without using alcoholic amines. Therefore, alcoholic amines exhibit remarkable advantages in the devulcanization of waste rubber, thus indicating a promising direction for the advancement of research in the area of waste rubber reclamation. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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14 pages, 787 KiB  
Article
Introducing “MEW2” Software: A Tool to Analyze MQ-NMR Experiments for Elastomers
by Fernando M. Salamanca, Zenen Zepeda-Rodríguez, Laura Diñeiro, Marina M. Escrivá, Rebeca Herrero, Rodrigo Navarro and Juan L. Valentín
Polymers 2023, 15(20), 4058; https://doi.org/10.3390/polym15204058 - 11 Oct 2023
Viewed by 1005
Abstract
Low-field time-domain proton Nuclear Magnetic Resonance (NMR) spectroscopy is an attractive and powerful tool for studying the structure and dynamics of elastomers. The existence of crosslinks and other topological constraints in rubber matrices (entanglements and filler–rubber interactions, among others) renders the fast segmental [...] Read more.
Low-field time-domain proton Nuclear Magnetic Resonance (NMR) spectroscopy is an attractive and powerful tool for studying the structure and dynamics of elastomers. The existence of crosslinks and other topological constraints in rubber matrices (entanglements and filler–rubber interactions, among others) renders the fast segmental fluctuations of the polymeric chains non-isotropic, obtaining nonzero residual dipolar couplings, which is the main observable of MQ-NMR experiments. A new software, Multiple quantum nuclear magnetic resonance analyzer for Elastomeric Networks v2 (MEW2), provides a new tool to facilitate the study of the molecular structure of elastomeric materials. This program quantitatively analyzes two different sets of experimental data obtained in the same experiment, which are dominated by multiple-quantum coherence and polymer dynamics. The proper quantification of non-coupled network defects (dangling chain ends, loops, etc.) allows the analyzer to normalize the multiple quantum intensity, obtaining a build-up curve that contains the structural information without any influence from the rubber dynamics. Finally, it provides the spatial distribution of crosslinks using a fast Tikhonov regularization process based on a statistical criterion. As a general trend, this study provides an automatic solution to a tedious procedure of analysis, demonstrating a new tool that accelerates the calculations of network structure using 1H MQ-NMR low-field time-domain experiments for elastomeric compounds. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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10 pages, 2761 KiB  
Article
Mechanical Properties of Ternary Composite from Waste Leather Fibers and Waste Polyamide Fibers with Acrylonitrile-Butadiene Rubber
by Le Thuy Hang, Quoc-Viet Do, Luu Hoang, Luc The Nguyen, Nguyen Pham Duy Linh and Vu Anh Doan
Polymers 2023, 15(11), 2453; https://doi.org/10.3390/polym15112453 - 25 May 2023
Cited by 1 | Viewed by 2084
Abstract
This study aimed to improve the mechanical properties of a composite material consisting of waste leather fibers (LF) and nitrile rubber (NBR) by partially replacing LF with waste polyamide fibers (PA). A ternary recycled composite NBR/LF/PA was produced by a simple mixing method [...] Read more.
This study aimed to improve the mechanical properties of a composite material consisting of waste leather fibers (LF) and nitrile rubber (NBR) by partially replacing LF with waste polyamide fibers (PA). A ternary recycled composite NBR/LF/PA was produced by a simple mixing method and vulcanized by compression molding. The mechanical properties and dynamic mechanical properties of the composite were investigated in detail. The results showed that the mechanical properties of NBR/LF/PA increased with an increase in the PA ratio. The highest tensile strength value of NBR/LF/PA was found to have increased about 1.26 times, that is from 12.9 MPa of LF50 to 16.3 MPa of LF25PA25. Additionally, the ternary composite demonstrated high hysteresis loss, which was confirmed by dynamic mechanical analysis (DMA). The presence of PA formed a non-woven network that significantly enhanced the abrasion resistance of the composite compared to NBR/LF. The failure mechanism was also analyzed through the observation of the failure surface using scanning electron microscopy (SEM). These findings suggest that the utilization of both waste fiber products together is a sustainable approach to reducing fibrous waste while improving the qualities of recycled rubber composites. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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19 pages, 7277 KiB  
Article
Modeling of Hyper-Viscoelastic Properties of High-Damping Rubber Materials during the Cyclic Tension and Compression Process in the Vertical Direction
by Bowen Chen, Junwu Dai and Zhipeng Shao
Polymers 2022, 14(24), 5395; https://doi.org/10.3390/polym14245395 - 09 Dec 2022
Viewed by 1255
Abstract
With the rapid development of the economy and urbanization, the construction of the urban rail transit system has had a great impact on the work, life, and health of residents in buildings along the rail transit line. Thus, it is particularly urgent and [...] Read more.
With the rapid development of the economy and urbanization, the construction of the urban rail transit system has had a great impact on the work, life, and health of residents in buildings along the rail transit line. Thus, it is particularly urgent and necessary to develop base isolation technologies to control and reduce the impact of vibrations of rail transit systems on building structures. High-damping rubber isolation bearings have shown significant effectiveness in the reduction of this impact, and their isolation performance mainly depends on the mechanical and damping energy dissipation characteristics of the high-damping rubber material. This paper aims to investigate the hyper-viscoelastic properties of the high-damping rubber material used for high-damping rubber isolation bearings during the cyclic tension and compression process in the vertical direction. These properties include hyperelastic parameters, viscoelastic coefficients, and the relaxation times of the material. For this purpose, uniaxial cyclic tension and compression tests were conducted. A three-element Maxwell rheological model combining a strain energy density function was proposed for modeling the hyper-viscoelastic behaviors of the materials during the cyclic tension and compression process. Based on the obtained results, an iterative identification procedure was used to determine the constitutive parameters of the material for each loading-unloading cycle. The aforementioned parameters were further expressed as a function of the number of cycles. New insights into hyper-viscoelastic property changes in this high-damping rubber material during the cyclic tension and compression process were gained in this work. These investigations could facilitate the development of computational tools, which would regulate fundamental guidelines for the better controlling and optimization of the isolation performance of the high-damping rubber material used for high-damping rubber isolation bearings, which have a wider perspective of applications in the urban rail transit system. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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17 pages, 3701 KiB  
Article
Ferric Ions Crosslinked Epoxidized Natural Rubber Filled with Carbon Nanotubes and Conductive Carbon Black Hybrid Fillers
by Kriengsak Damampai, Skulrat Pichaiyut, Klaus Werner Stöckelhuber, Amit Das and Charoen Nakason
Polymers 2022, 14(20), 4392; https://doi.org/10.3390/polym14204392 - 18 Oct 2022
Cited by 6 | Viewed by 1521
Abstract
Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe3+ [...] Read more.
Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe3+) as a crosslinking agent. The ENRs filled exclusively with CNTs, and CNT–CCB hybrid fillers exhibited typical curing curves at different CCB loadings, i.e., increasing torque with time and thus crosslinked networks. Furthermore, the incorporation of CNT–CCB hybrid fillers and increasing CCB loadings caused an enhancement of tensile properties (modulus and tensile strength) and crosslink densities, which are indicated by the increasing torque difference and the crosslink densities. The crosslink densities are determined by swelling and temperature scanning stress relaxation (TSSR). Increasing CCB loadings also caused a significant improvement in bound rubber content, filler–rubber interactions, thermal resistance, glass transition temperature (Tg) and electrical conductivity. A combination of 7 phr CNT and CCB with loading higher than 2.5 phr gave superior properties to ENR vulcanizates. Furthermore, the secondary CCB filler contributes to the improvement of CNT dispersion in the ENR matrix by networking the CNT capsules and forming CNT–CCB–CNT pathways and thus strong CNT–CCB networks, indicating the improvement in the tensile properties, bound rubber content and dynamic properties of the ENR composites. Moreover, higher electrical conductivity with a comparatively low percolation threshold of the hybrid composites was found as compared to the ENR filled with CNTs without CCB composite. The superior mechanical and other properties are due to the finer dispersion and even distribution of CNT–CCB hybrid fillers in the ENR matrix. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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18 pages, 11424 KiB  
Article
Study on Increasing the Binding Amount of Rubber and Reinforcing Filler by Adding Aromatic Solvent Oil
by Xiaoqing Li, Zhonghang Fang, Xinmin Shen, Qin Yin, Zhiyuan Chen, Qunzhang Tu and Ming Pan
Polymers 2022, 14(13), 2745; https://doi.org/10.3390/polym14132745 - 05 Jul 2022
Cited by 3 | Viewed by 1829
Abstract
The binding amount of rubber and reinforcing filler directly affects the quality of rubber products. The effect of aromatic solvent oil (S-150) on the binding amount of rubber and reinforcing filler was studied. In order to determine the suitability of rubber after adding [...] Read more.
The binding amount of rubber and reinforcing filler directly affects the quality of rubber products. The effect of aromatic solvent oil (S-150) on the binding amount of rubber and reinforcing filler was studied. In order to determine the suitability of rubber after adding S-150, the curing characteristics, physical performance and tensile properties of rubber samples were tested and analyzed. Meanwhile, the microstructure of the composite was analyzed by scanning electron microscopy (SEM). The test results showed that the binding amount of rubber and reinforcing filler was increased after adding S-150. The density and Shore A hardness were decreased. When carbon black was 80 phr, after adding 40 phr of S-150, the rebound resilience of rubber increased by 13% on average, and the elongation at break increased by 88% on average. When white carbon black was between 10-70 phr, after adding 65 phr of S-150, the rebound resilience of rubber increased by 9% on average, and the elongation at break increased by 51% on average. Modulus at 100% and tensile strength were decreased. Meanwhile, it could be judged from the microstructure results that the reticulation space inside the rubber was increased, the agglomerate particles were relatively uniform, and no bubbles or holes were observed. The mechanism that S-150 could increase the binding amount of rubber was analyzed according to the like-dissolves-like principle. This research achievement could lead to improvements in the quality of rubber products and promote their practical application. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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Review

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24 pages, 5470 KiB  
Review
Synthetic Polyisoprene Rubber as a Mimic of Natural Rubber: Recent Advances on Synthesis, Nanocomposites, and Applications
by Jorge A. Cruz-Morales, Carina Gutiérrez-Flores, Daniel Zárate-Saldaña, Manuel Burelo, Héctor García-Ortega and Selena Gutiérrez
Polymers 2023, 15(20), 4074; https://doi.org/10.3390/polym15204074 - 13 Oct 2023
Cited by 3 | Viewed by 2173
Abstract
Up to now, rubber materials have been used in a wide range of applications, from automotive parts to special-design engineering pieces, as well as in the pharmaceutical, food, electronics, and military industries, among others. Since the discovery of the vulcanization of natural rubber [...] Read more.
Up to now, rubber materials have been used in a wide range of applications, from automotive parts to special-design engineering pieces, as well as in the pharmaceutical, food, electronics, and military industries, among others. Since the discovery of the vulcanization of natural rubber (NR) in 1838, the continuous demand for this material has intensified the quest for a synthetic substitute with similar properties. In this regard, synthetic polyisoprene rubber (IR) emerged as an attractive alternative. However, despite the efforts made, some properties of natural rubber have been difficult to match (i.e., superior mechanical properties) due not only to its high content of cis-1,4-polyisoprene but also because its structure is considered a naturally occurring nanocomposite. In this sense, cutting-edge research has proposed the synthesis of nanocomposites with synthetic rubber, obtaining the same properties as natural rubber. This review focuses on the synthesis, structure, and properties of natural and synthetic rubber, with a special interest in the synthesis of IR nanocomposites, giving the reader a comprehensive reference on how to achieve a mimic of NR. Full article
(This article belongs to the Special Issue Advances in Rubbers)
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