scholarly journals Rosin-Based Epoxy Vitrimers with Dynamic Boronic Ester Bonds

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3386
Author(s):  
Yanning Zeng ◽  
Jiawei Li ◽  
Shuxin Liu ◽  
Bin Yang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Analysis ◽  
Chemical Degradation ◽  
Self Healing ◽  
Hot Press ◽  
Boronic Ester ◽  
Network Topologies ◽  
Reversible Covalent ◽  
First Time ◽  
Epoxy Groups

Rosin is an abundantly available natural product. In this paper, for the first time, a rosin derivative is employed as the main monomer for preparation of epoxy vitrimers to improve the mechanical properties of vitrimers. Novel epoxy vitrimer networks with dynamic reversible covalent boronic ester bonds are constructed by a reaction between thiols in 2,2′–(1,4–phenylene)–bis (4–mercaptan–1,3,2–dioxaborolane) (BDB) as a curing agent and epoxy groups in the rosin derivative. The rosin-based epoxy vitrimer networks are fully characterized by Fourier transform infrared spectroscopy (FTIR), an equilibrium swelling experiment, and dynamic mechanical analysis (DMA). The obtained rosin-based epoxy vitrimers possess superior thermostability and good mechanical properties. Due to transesterification of boronic ester bonds, rosin epoxy vitrimer network topologies can be altered, giving welding, recycle, self-healing, and shape memory abilities to the fabricated polymer. Besides, the effects of treating time and temperature on welding capability is investigated, and it is found that the welding efficiency of the 20% C-FPAE sample is >93% after treatment for 12 h at 160 °C. Moreover, through a hot press, the pulverized samples of 20% C-FPAE can be reshaped several times and most mechanical properties are restored after reprocessing at 200 °C for 60 min. Finally, chemical degradation is researched for the rosin-based epoxy vitrimers.

scholarly journals Sustainable Polyurethane Networks Based on Rosin with Reprocessing Performance

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3538
Author(s):  
Jiawei Li ◽  
Weiming Yang ◽  
Zhao Ning ◽  
Bin Yang ◽  
Yanning Zeng
Keyword(s):  
Mechanical Properties ◽  
Mechanical Analysis ◽  
Healing Time ◽  
The Self ◽  
Self Healing ◽  
Hot Press ◽  
Polyurethane Networks ◽  
Network Topologies ◽  
Superior Mechanical Properties ◽  
First Time

Rosin is an abundant natural product. In this paper, for the first time, a rosin derivative is employed as a monomer for the preparation of polyurethane vitrimers with improved properties. A novel rosin-based polyurethane vitrimers network was constructed by the reaction between isocyanates (HDI) as curing agent and monomers with alcohol groups modified from rosin. The dynamic rosin-based polyurethane vitrimers were characterized by FTIR and dynamic mechanical analysis. The obtained rosin-based polyurethane vitrimers possessed superior mechanical properties. Due to the dynamic urethane linkages, the network topologies of rosin-based polyurethane vitrimers could be altered, contributing self-healing and reprocessing abilities. Besides, we investigated the effects of healing time and temperature on the self-healing performance. Moreover, through a hot press, pulverized samples of 70%VPUOH could be reshaped several times, and the mechanical properties of the recycled samples were restored, with tensile strength being even higher than the of that of the original samples.

scholarly journals Self-Healing Photocurable Epoxy/thiol-ene Systems Using an Aromatic Epoxy Resin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ricardo Acosta Ortiz ◽  
Omar Acosta Berlanga ◽  
Aída Esmeralda García Valdez ◽  
Rafael Aguirre Flores ◽  
José Guadalupe Télles Padilla ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Hypervalent Iodine ◽  
Self Healing ◽  
Healing Efficiency ◽  
Kinetics Of ◽  
Epoxy Groups

A rapid and efficient method to obtain self-healing epoxy resins is discussed. This method is based on the use of a thiol-disulfide oligomer obtained by partial oxidation of a multifunctional thiol using a hypervalent iodine (III) compound as oxidant. The oligomer was characterized by Fourier transform infrared spectroscopy (FTIR), Raman and nuclear magnetic resonance spectroscopies, and gel permeation chromatography (GPC). The oligomer was a joint component of the thiol-ene system along with a tetra-allyl-functionalized curing agent. The kinetics of the photopolymerization of diglycidylether of bisphenol A (DGEBA) revealed that conversions of the epoxy groups as high as 80% were achieved in only 15 minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the copolymer using the thiol-disulfide oligomer allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80°C or for 500 minutes at room temperature. The analysis of the mechanical properties using dynamic mechanical analysis (DMA) showed that the specimens displayed a healing efficiency up to 111% compared with the unhealed specimens, depending on the amount of polythioethers present in the copolymer.

scholarly journals Internal and external catalysis in boronic ester networks

2021 ◽  
Author(s):  
Boyeong Kang ◽  
Julia Kalow
Keyword(s):  
Mechanical Properties ◽  
Binding Affinity ◽  
Polymer Networks ◽  
Model Systems ◽  
Self Healing ◽  
Dynamic Materials ◽  
Boronic Ester ◽  
Rate Acceleration ◽  
Exchange Spectroscopy ◽  
Kinetics Of

In dynamic materials, the reversible condensation between boronic acids and diols provides adaptability, self-healing ability, and responsiveness to small molecules and pH. Recent work has shown that the thermodynamics and kinetics of bond exchange determine the mechanical properties of dynamic polymer networks. However, prior studies have focused on how structural and environmental factors influence boronic acid–diol binding affinity, and design rules for tuning the kinetics of this dynamic bond are lacking. In this work, we investigate the effects of diol (or polyol) structure and salt additives on the rate of bond exchange, binding affinity, and the mechanical properties of the corresponding polymer networks. To better mimic the environment of polymer networks in our small-molecule model systems, we incorporated proximal amide groups, which are used to conjugate diols to polymers, and included salts commonly found in buffers. Using one-dimensional selective exchange spectroscopy (1D EXSY), we find that both proximal amides and buffering anions induce significant rate acceleration consistent with internal and external catalysis, respectively. This rate acceleration is reflected in the stress relaxation of gels formed using PEG modified with different alcohols, and in the presence of salts containing acetate or phosphate. These findings contribute to the fundamental understanding of the boronic ester dynamic bond and offer new molecular strategies to tune the macromolecular properties of dynamic materials.

Preparation and properties of self-healing polyether amines based on Diels–Alder reversible covalent bonds

2018 ◽  
Vol 31 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Xiaofei Wang ◽  
Kaifeng Zhao ◽  
Xiaowen Huang ◽  
Xiaoyue Ma ◽  
Yanyan Wei
Keyword(s):  
Glycidyl Ether ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Diels Alder ◽  
Proton Nuclear Magnetic Resonance ◽  
Self Healing ◽  
Covalent Bonds ◽  
Reversible Covalent ◽  
Automotive Coating

Over time, automotive coating is bound to be damaged; therefore, it is necessary to give the coating a self-healing ability to make its performance even better. First, furfuryl glycidyl ether (FGE) was synthesized by epichlorohydrin and furfuryl alcohol. Then, furanyl-terminated resin FGE-T5000 was synthesized by polyether amine T5000 and FGE. Finally, 4,4′-diphenylmethane bismaleimide (BDM) was added to FGE-T5000 as a cross-linking agent to form a resin named FGE-T5000-BDM which has Diels–Alder (DA) bonds. The products were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance, differential scanning calorimeter, dynamic mechanical analysis, thermogravimetric analysis, optical microscope, tensile tests, and other tests. The results showed that FGE-T5000-BDM demonstrated thermally reversible self-healing property from 50°C to 150°C, and that the best temperature of the DA reaction was 80°C. The gel content of FGE-T5000-BDM was 98%. Also, the glass transition temperature and the initial temperature of the Retro-DA (r-DA) reaction were −58°C and 88°C, respectively. Moreover, the self-healing efficiency of FGE-T5000-BDM was up to 88% after staying at 80°C for 12 h. The innovation shown in this article was that the reversible covalent bonds (DA) were combined with the polyether amines, which produced the characteristics of self-healing. Its unique self-healing properties are useful in some areas, such as automobile coatings and other materials.

scholarly journals Self-Healing and Mechanical Properties of Thermoplastic Polyurethane/Eugenol-Based Phenoxy Resin Blends via Exchange Reactions

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1011 ◽  
Author(s):  
Jing-Yu Liang ◽  
Se-Ra Shin ◽  
Soo-Hyoung Lee ◽  
Dai-Soo Lee
Keyword(s):  
Mechanical Properties ◽  
Exchange Reaction ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Resin Content ◽  
Self Healing ◽  
Exchange Reactions ◽  
Scanning Calorimetry ◽  
Healing Efficiency ◽  
Different Types

The possibility of exchange reactions and thermal self-healing in blends of thermoplastic polyurethane (TPU) and phenoxy resin was investigated herein. The analyses were based on characterization obtained via differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), and tensile test. A new phenoxy resin was synthesized from eugenol, and blends with different types of TPU were prepared to investigate the exchange reaction, thermal self-healing, and mechanical properties. The influence of phenoxy resin content on the mechanical behavior and healing efficiency was studied. Improvement of storage modulus owing to the increase of phenoxy resin content was observed. Results suggest that the exchange reaction between phenoxy- and ester-type TPU occurred during thermal treatment. However, little exchange occurred between phenoxy resin and ether-type TPU. Specifically, only ester-type TPU exhibited a significant exchange reaction in the phenoxy resin blend. Furthermore, in the presence of a catalyst (e.g., zinc acetate), the exchange reaction readily occurred, and the healing efficiency improved by the addition of the catalyst and increase in the phenoxy content.

Softening of High-Strength Steel for Laser Assisted Clinching

2014 ◽  
Vol 966-967 ◽  
pp. 617-627 ◽  
Author(s):  
Julia Osten ◽  
Paul Söllig ◽  
Michael Reich ◽  
Jan Kalich ◽  
Uwe Füssel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Laser Heating ◽  
High Strength Steels ◽  
High Strength ◽  
Mechanical Analysis ◽  
Hardened Steel ◽  
The Press ◽  
Short Time ◽  
First Time

The conventional clinching of steels is currently limited to tensile strength less than 800 N/mm2 and to elongation at fracture more than 14 %. To realise the clinching of high-strength steels, the sheet can be heated locally at the joint, to improve ductility. Thereby the material characteristics outside the joint should be maintained. This could be achieved by means of short-time laser heating. The short-time tempering behaviour of press hardened steel 22MnB5 has been analysed. The mechanical properties during a short-time heat treatment were investigated by thermo-mechanical analysis in a deformation dilatometer. Thereby laser-assisted clinching shall be established and an efficient form-closed and force-closed connection shall be produced. As a result, the press hardened steel 22MnB5 could be clinched by laser assistance for the very first time.

Synergy between dynamic covalent boronic ester and boron–nitrogen coordination: strategy for self-healing polyurethane elastomers at room temperature with unprecedented mechanical properties

2021 ◽  
Author(s):  
Kai Song ◽  
Wujin Ye ◽  
Xingchen Gao ◽  
Huagao Fang ◽  
Yaqiong Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Interactions ◽  
Room Temperature ◽  
Self Healing ◽  
Polyurethane Elastomers ◽  
Coordination Strategy ◽  
Boronic Ester ◽  
Healing Efficiency ◽  
Boron Nitrogen

Boron–nitrogen coordination in polyurethane elastomers enhances the dynamics of the boronic ester while introduces inter- and intra-molecular interactions, leading to mechanical robustness and excellent self-healing efficiency simultaneously.

scholarly journals Dynamic Semi IPNs with Duple Dynamic Linkers: Self-Healing, Reprocessing, Welding, and Shape Memory Behaviors

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1679
Author(s):  
Yanning Zeng ◽  
Weiming Yang ◽  
Shuxin Liu ◽  
Xiahui Shi ◽  
Aoqian Xi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Material Properties ◽  
Dynamic Properties ◽  
Thermoplastic Polyurethane ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Diels Alder ◽  
Self Healing ◽  
Boronic Ester

Thermoset polymers show favorable material properties, while bringing about environmental pollution due to non-reprocessing and unrecyclable. Diels–Alder (DA) chemistry or reversible exchange boronic ester bonds have been employed to fabricate recycled polymers with covalent adaptable networks (CANs). Herein, a novel type of CANs with multiple dynamic linkers (DA chemistry and boronic ester bonds) was firstly constructed based on a linear copolymer of styrene and furfuryl methacrylate and boronic ester crosslinker. Thermoplastic polyurethane is introduced into the CANs to give a semi Interpenetrating Polymer Networks (semi IPNs) to enhance the properties of the CANs. We describe the synthesis and dynamic properties of semi IPNs. Because of the DA reaction and transesterification of boronic ester bonds, the topologies of semi IPNs can be altered, contributing to the reprocessing, self-healing, welding, and shape memory behaviors of the produced polymer. Through a microinjection technique, the cut samples of the semi IPNs can be reshaped and mechanical properties of the recycled samples can be well-restored after being remolded at 190 °C for 5 min.

Autonomous self-healing polyisoprene elastomers with high modulus and good toughness based on the synergy of dynamic ionic crosslinks and highly disordered crystals

2020 ◽  
Vol 11 (41) ◽  
pp. 6549-6558
Author(s):  
Yohei Miwa ◽  
Mayu Yamada ◽  
Yu Shinke ◽  
Shoichi Kutsumizu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Self Healing ◽  
High Modulus ◽  
Disordered Crystals ◽  
Ionic Crosslinks

We designed a novel polyisoprene elastomer with high mechanical properties and autonomous self-healing capability at room temperature facilitated by the coexistence of dynamic ionic crosslinks and crystalline components that slowly reassembled.

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