Introducing metal-ligand coordination interaction for self-healing and recyclable nitrile–butadiene rubber: A facile strategy
Yuan Gao, Weiran Zhang, Junhao Wang, Zishuo Wang, Zhaobo Wang
Vol. 17., No.10., Pages 1019-1030, 2023
DOI: 10.3144/expresspolymlett.2023.76
DOI: 10.3144/expresspolymlett.2023.76
Corresponding author: Zhaobo Wang 
GRAPHICAL ABSTRACT
ABSTRACT
In this research, a nitrile-butadiene rubber (NBR) was prepared with excellent mechanical, self-healing and recycling properties by introducing metal-ligand coordination interaction. A coordination crosslinking network based on ligand bonding was successfully introduced in the NBR matrix by mechanical compounding. The dynamic reversibility of the coordination crosslinking network not only provides the vulcanizate with excellent mechanical properties but also confers a remarkable self-healing ability under high temperatures and recyclable property under mechanical shear, respectively. The sample, which was subjected to the complete cut, could be capable of restoring its original tensile strength after self-healing treatment. The self-healing efficiency of NBR vulcanizate is significantly dependent on the self-healing temperature and time, which can surprisingly reach 97% of the original tensile strength after self-healing treatment at 180 °C for 60 min. After the mechanical shear, the coordination crosslinking network is reversibly transformed. The tensile strength of the NBR vulcanizates after mechanical shearing recycling and re-vulcanization was similar to that of the original NBR vulcanizates. This research presents a novel approach to enhance the durability of rubber used in commercial applications, endowing it with reshaping and recycling capabilities and mitigating environmental issues associated with waste rubber.
RELATED ARTICLES
Shengao Yang, Yan Wang, Fang Wang, Kaiyi Zhang, Xinxin Lv, Hao Teng, Rui Zheng, Faliang Luo, Qian Xing
Vol. 19., No.1., Pages 94-106, 2025
DOI: 10.3144/expresspolymlett.2025.7
Vol. 19., No.1., Pages 94-106, 2025
DOI: 10.3144/expresspolymlett.2025.7
Dynamic cross-linked networks (DCNs) endow thermoset rubber with self-healability and recyclability to extend its lifetime and alleviate environmental pollution. However, the contradiction between high self-healing and mechanical properties in DCNs rubber is always difficult to be resolved. Herein, we used boronic ester (BO) and Diels-Alder dynamic covalent bonds (DA) to synthesize polybutadiene-based dual networks rubber (PB-BO-DA) via thiol-ene reaction. This approach achieved a tensile strength of 16.46 MPa and 99% self-healing efficiency, facilitated by extensive intermolecular interactions (π-π packing and N-B coordination) and fully dynamic cross-linking. In addition, multiple dynamic cross-linked networks (MDCNs) polybutadiene-based rubber also show excellent shape memory ability and recyclability. This strategy might open a helpful pathway to fabricate intelligent multifunctional polymers with high strength and high self-healing efficiency.
Agata Rodak, Józef Haponiuk, Shifeng Wang, Krzysztof Formela
Vol. 18., No.12., Pages 1191-1208, 2024
DOI: 10.3144/expresspolymlett.2024.91
Vol. 18., No.12., Pages 1191-1208, 2024
DOI: 10.3144/expresspolymlett.2024.91
Carbon black migration between ground tire rubber (GTR) and rubber matrix is essential in developing high-performance rubber/GTR composites. In this work, carbon black N220 (surface area: 107.1 m2/g, particle size: 20–25 nm) and N660 (surface area: 33.1 m2/g, particle size: 49–60 nm) were used as the reinforcement fillers for styrene-butadiene rubber (SBR) blended with reclaimed GTR. The combined effects of GTR devulcanization level and carbon black grade on the properties of SBR/GTR composites were investigated considering curing characteristics, thermal stability, physico-mechanical properties, dynamic mechanical properties, swelling behavior, and morphology. The results showed that, regardless of GTR devulcanization level and carbon black grade, application of GTR resulted in deterioration of mechanical properties compared to a reference sample without GTR. It was observed the reinforcement effect of carbon black in SBR/GTR composites was more visible with higher devulcanization level of GTR and lower particle sizes of carbon black fillers. SBR/GTR composites reinforced with carbon black N220 were characterized by tensile strength in the range of 15.3–16.3 MPa and abrasion resistance in the range of 120–123 mm3, which justify their potential application in the manufacturing of technical rubber goods or footwear.
Xavier Colom, Mohammad Reza Saeb, Javier Cañavate
Vol. 18., No.9., Pages 950-961, 2024
DOI: 10.3144/expresspolymlett.2024.72
Vol. 18., No.9., Pages 950-961, 2024
DOI: 10.3144/expresspolymlett.2024.72
Analyzing rubber waste is crucial for value-added recycling, but the multitude of ingredients in vulcanized networks makes it challenging to characterize cross-linked rubbers. A combination of analytical techniques is usually required. In this study, two complementary characterization techniques, based on Fourier transform infrared (FTIR) spectroscopy and derivative thermogravimetric analysis (DTGA) were applied to analyze the structural, physical, and thermal behavior of ground tire rubber (GTR) samples devulcanized by two different processes. A set of samples was devulcanized by only microwaves (MW) while another set was treated with a combination of a thermochemomechanical (TM) process, which included the use of a devulcanization aid such as benzoyl peroxide, and microwaves. The combined technique proved to be more efficient in terms of the degree of devulcanization, significantly reducing the cross-linking density. However, the combined thermochemomechanical and microwave (TM/MW) devulcanization process resulted in greater degradation of the main rubber chains in the cross-linked network compared to the process using only microwaves.
Yiting Jing, Sufang Chen, Zejun Xu, Tingcheng Li, Daohong Zhang
Vol. 17., No.12., Pages 1200-1211, 2023
DOI: 10.3144/expresspolymlett.2023.91
Vol. 17., No.12., Pages 1200-1211, 2023
DOI: 10.3144/expresspolymlett.2023.91
Adhesives have been widely applied in various fields. However, most industrial adhesives contain organic solvents, which are toxic and difficult to clean after use. Importantly, most adhesives are used in a relatively small temperature range (0–50 °C), which is due to the fragmentation of the morphology and properties of supramolecular polymer gels at low temperatures. Most of the supramolecular adhesives need to be heated during the bonding process, which cannot meet the requirements of low-temperature adhesion in daily life and industry. In this study, based on the concept of using deep eutectic solvents (DESs) as a platform, cyclodextrin (β-CD) and carboxyl terminated hyperbranched polyester (DCHP) were used to prepare solvent-free supramolecular polymer gel (CD-DCHP), which was non-toxic and easy to clean. Due to the joint action of deep eutectic solvent and supramolecular polymer structure, CD-DCHP showed excellent mechanical properties, super strong adhesion (up to 4.55 MPa on glass surface), and excellent low-temperature performance (up to 1.64 MPa at –60 °C). This supramolecular polymer gel also showed excellent tolerance to acids, alkalis, and various organic solvents. It greatly expanded the application of DES and provided a new approach to the development of supramolecular adhesives.
