ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Hongkun Yang,Dong Wang
We used atomic force microscopy-based infrared spectroscopy (AFM-IR) and nanomechanical mapping (AFM-NM) to image the surface of a vitrimer, specifically dicarboxylic acid-cured diglycidyl ether of bisphenol A (DGEBA), to assess the curing process of a surface layer and compared this to the process in the bulk. We identified the β-hydroxy esters with various functionalities that are the key to form the cross-links for a system, including difunctional DGEBA and carboxylic acids. The IR peaks of the carbonyl group in generated ester groups are distinguished clearly from those in acids, allowing us to quantitatively assess the curing process at the surface and in the bulk. The initial curing at the surface exhibits a gradual cross-linking and is found to be lower than a rapid cross-linking in the bulk due to a relatively lower concentration of the β-hydroxy esters with high functionalities. This curing process leads to a smaller chemically and mechanically heterogeneous nanostructure at the surface relative to the bulk. After multiple reprocessings, a substantial number of esters lacking dynamic exchange capability form in the bulk, which decrease the flowability and reprocessability of the vitrimers and therefore the mechanical properties.
研究领域:
高分子化学
·
材料科学
·
纳米技术
·
表面科学
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DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2025
·
IF 7.4
Daquan Wang,Zuoliang Zhang,Xin Xu,Yao Qiu,Gang Chang,Kaiyun Yuan,Ruqing Xu,Lingjie Meng
The widespread application of epoxy resins in thermosetting materials is limited by inadequate flame retardancy and recyclability. This study reports the synthesis of a bio-based, hexafunctional star-shaped epoxy cyclotriphosphazene (NEP) via nucleophilic substitution and oxidation of hexachlorocyclotriphosphazene and eugenol. An intrinsically flame-retardant epoxy vitrimer (EV/NEP) was subsequently prepared, exhibiting superior mechanical properties, heat resistance, and thermal stability. Incorporation of 9 mol % NEP significantly enhanced flame retardancy, increasing the limiting oxygen index (LOI) to 26.2 % while reducing peak heat release rate (PHRR) and total smoke release (TSR) by 24.9 % and 35.4 %, respectively. Flame retardancy mechanisms were elucidated in both solid and gas phases. Recyclability was confirmed through solvent recovery and thermal compression experiments. Dynamic ester bonds conferred excellent shape memory properties to EV/NEP. The combination of flame retardancy and recyclability makes this epoxy vitrimer a promising candidate for aerospace and automotive applications.
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2023
·Vol. 41
·期 17
·2125-2131
·
IF 5.4
Yunlong Ma,Ruiyang Li,Shichang Luo,Xiran Shen,Rao Tao,Yinghua Jin,Wei Zhang,Li Qiu
Comprehensive Summary Although polyimides (PIs) have shown great potential for a broad range of applications, it remains very challenging to achieve the malleability, rehealability and recyclability for PIs and their composites targeting various applications, particularly for the rapidly emerging flexible and stretchable electronics. Herein, malleable conductive poly(imide-imine) hybrid (PIIH) vitrimer-graphene aerogel (GA) composites have been prepared, for the first time, via simple sol-gel film formation followed by heat-press. The resulting PIIH-GA composites exhibit not only the highly desired properties of thermosetting (strong mechanical strength) and thermoplastic (reprocessability) polymers, but also good conductivity enabled by the GA filler. PIIH3-GA-10 (with 10 wt% GA) showed one of the highest electrical conductivities (26.7 S/m) for PI-based composites, as well as good electromagnetic interference (EMI) shielding performance. Moreover, the PIIH-GA films could maintain good performance during stretching and even after chemical recycling, which opens new opportunities for flexible and sustainable electronics development.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Xiling Niu,Fenfen Wang,Xiaohui Li,Rongchun Zhang,Qiang Wu,Pingchuan Sun
Vitrimers are fascinating thermoset polymers to the industry since they can be recycled and reprocessed without compromising their mechanical strength and solvent resistance. Particularly, transesterification reaction in the epoxy resin (ER) vitrimers usually requires the incorporation of a catalyst, whereas most reports only focused on investigating the catalytic effect of small molecules, such as zinc acetate (Zn(OAc)2) and triazabicyclodecene (TBD). In this work, a polymer catalyst, poly(acrylonitrile-co-zinc methacrylate) (Zn-PAM), was synthesized by the random copolymerization of zinc methacrylate and acrylonitrile, where the transesterification catalysis efficiency of Zn-PAM was systematically investigated and compared to that of Zn(OAc)2 and TBD by temperature-dependent stress relaxation experiments. It was revealed that Zn-PAM has a higher catalysis efficiency than Zn(OAc)2 and TBD under the same loading between Zn2+ and TBD. Besides, only a tiny amount of polymer catalyst is needed to efficiently catalyze the transesterification reaction while in the meantime enhance the mechanical properties of ER.
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DOI
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Jinye Zhang,Zepeng Lei,Shichang Luo,Yinghua Jin,Li Qiu,Wei Zhang
A novel conductive composite consisting of polyimine vitrimer matrix and multiwalled carbon nanotube (MWCNT) filler that allows bending, stretching, rehealing, and closed-loop recycling was developed. Such composites can be easily prepared by simply heating a mixed solution of the polyimine precursors and less than 10 wt % of MWCNTs. The resulting composites combine both advantages of the polyimine vitrimer (i.e., dynamic covalent bond exchange) and carbon nanotubes (i.e., electron conducting), and the as-fabricated thin films exhibit malleability, rehealability, recyclability and good electron conductivity. Impressively, the electrical conductivity of the composite could remain almost the same after bending, reshaping, rehealing, and reuse, thus making it an excellent candidate for flexible electronics. Moreover, such composites can also be fully recycled at the end of their service life, which would greatly reduce the electronic waste, manufacturing cost, and environmental impact.
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DOI
Science Advances
·
2024
·Vol. 10
·期 10
·
IF 11.7
Ziguang Zhao,Ziquan Cao,Zhixin Wu,Wenxin Du,Xue Meng,Huawei Chen,Yuchen Wu,Lei Jiang,Mingjie Liu
Currently, it remains challenging to balance intrinsic stiffness with programmability in most vitrimers. Simultaneously, coordinating materials with gel-like iontronic properties for intrinsic ion transmission while maintaining vitrimer programmable features remains underexplored. Here, we introduce a phase-engineering strategy to fabricate bicontinuous vitrimer heterogel (VHG) materials. Such VHGs exhibited high mechanical strength, with an elastic modulus of up to 116 MPa, a high strain performance exceeding 1000%, and a switchable stiffness ratio surpassing 5 × 103. Moreover, highly programmable reprocessing and shape memory morphing were realized owing to the ion liquid–enhanced VHG network reconfiguration. Derived from the ion transmission pathway in the ILgel, which responded to the wide-span switchable mechanics, the VHG iontronics had a unique bidirectional stiffness-gated piezoresistivity, coordinating both positive and negative piezoresistive properties. Our findings indicate that the VHG system can act as a foundational material in various promising applications, including smart sensors, soft machines, and bioelectronics.
研究领域:
材料科学
·
软体机器人
·
生物电子学
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DOI
PubMed
高影响因子
Small
·
2025
·Vol. 21
·期 42
·e08062
·
IF 12.1
Hengheng Zhao,Sai Li,Ganggang Zhang,Haoxiang Li,Liqun Zhang,Venkat Ganesan,Jun Liu
Reconciliation of the elasticity, reinforcement, and recyclability in elastomer nanocomposites (ENCs) remains challenging, primarily due to the energy losses of the friction at polymer-nanoparticle interfaces and the permanent covalent cross-linking. Here, a self-adaptive soft interface strategy is introduced, using modulus-tuned polymer nanoparticles (PNPs) as reinforcement agents and interfacial chemical cross-linking sites within a vitrimer elastomer matrix. Such a framework promotes synergistic deformation of the PNPs with the matrix chains during mechanical deformation to minimize energy dissipation. Compared to traditional inorganic filler systems, these deformable PNPs exhibit exceptional compatibility and uniform dispersion, endowing the PNPs-filled ENCs with high mechanical strength, elongation at break, toughness, and low hysteresis loss. Moreover, the dynamic covalent bonds both in the matrix and interface impart excellent reprocessability and recyclability at elevated temperature, such as maintaining 88% of the mechanical performances after ten recycling cycles. This work puts forward a high additional value approach to produce PNPs, which are compounded with elastomer matrix with covalent adaptable networks to successfully balance the long-standing irreconcilable elasticity, reinforcement, and recycling, thus opening a new avenue for the development of next generation high performance and eco-friendly ENCs.
研究领域:
高分子科学
·
材料化学
·
纳米复合材料
·
软物质物理
·
可持续材料
·
力学性能调控
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DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 26
·12111-12127
·
IF 3.5
Zhao Yanna,Bai Xiaowei,Zhang Yingying,Wang Yuqi,Huang Yuqing,Hou Wentong
Acylhydrazone bonds can participate in dynamic exchange reactions under acid-stimulated conditions, and disulfide bonds can participate in dynamic exchange reactions under thermally stimulated conditions. It is of great significance to prepare epoxy vitrimer that can rapidly self-repair under acid and thermal stimulation conditions. In this paper, vanillin was used as raw material, and monomer (VAN-AD) containing acylhydrazone bond was synthesized by reaction with adipic dihydrazide. Then, VAN-AD and 4-aminophenyl disulfide (SS) were cured together with glycerol triglycidyl ether to prepare an epoxy vitrimer with acylhydrazone and disulfide dual dynamic covalent bonds. Where VAN-AD provides some of the flexible chain segments and acylhydrazone bonds and SS provides the aromatic phenyl and disulfide bonds. The material was prepared in a simple process and under mild condition, and the properties of the material were optimized by changing the ratio of VAN-AD to SS. The T g of the material was 50 °C when the ratio of SS was the highest, the thermal stability was enhanced with the increase of the ratio of SS, and the maximum tensile strength up to 50.9 MPa, and the material can be completely degraded by DMF with 5% HCl. It is worth noting that the material shows rapid self-healing properties under acid-heat conditions, self-healing rates up to 97.37%, and the tensile strength can reach 26 MPa after repair. The material can be successfully remodeled by hot pressing for 1 h at 140 °C and 10 MPa. Graphical abstract
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 48
·e56281
·
IF 2.7
Yanna Zhao,Yingying Zhang,Xiaowei Bai,Yuqi Wang,Yiqing Li,Shuai Yang
Polyimide materials with high mechanical strength are widely used in various fields, but pose certain challenges in achieving sustainable material utilization. A poly(imide-imide) vitrimer material (ADTA) based on multiple dynamic covalent bonds (imide, imine, and disulfide bonds) was constructed by preparing vanillin difunctionalized derivatives (DVA) for aldolamine condensation reactions with bis-amine monomers (ATFA) and tris(2-aminoethyl) amines (TAEA) with imide structures. The ADTA material has good 5% thermal stability T d 5% (278.87°C), high energy storage modulus E (2421.26 MPa), and fast relaxation time (36.39 s). The thermal stability and mechanical properties of the material are enhanced by the more stable alicyclic structure of the imide structure. The material also demonstrated excellent solvent resistance and self-healing properties. This study provides a new option for the development of sustainable utilization of polyimide materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Zhiping Su,Lan Cui,Huanhuan Zhang,Lei Xiao,Bing Chi,Haiayan Xu,Liping Ning,Shanshan Jia,Xiaohui Wang
The increasing application of non-degradable petroleum-based plastics has resulted in serious environmental pollution . Renewable and degradable cellulose-based materials are attractive candidates to replace petroleum-based plastics. However, the strong hydrogen bond (H-bond) interactions of cellulose result in its poor plastic formability such as thermoforming. Herein, a novel and effective thermoforming method of cellulose was developed by modifying cellulose into cellulose-based polyimine vitrimer (Cel-PI) via introducing dynamic imine bonds between cellulose molecular chains using Schiff-base reaction. The presence of dynamic imine bonds enables the heat-induced dynamic exchange and stress relaxation behavior of Cel-PI networks, making the excellent thermo-processability of Cel-PI. The as-synthesized Cel-PI powders can be easily thermoformed into Cel-PI film via heat-pressing approach without adding any plasticizers . The resulting Cel-PI film exhibits high Young’s modulus (2.9 GPa), high strength (46.3 MPa), good self-healing ability, excellent waterproof capability and organic solvent stability, and high thermal stability. Moreover, it can be chemically degraded, biodegraded, and recycled. Therefore, Cel-PI represents a promising and sustainable petroleum-based plastic replacement.
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DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2023
·Vol. 33
·期 16
·2215055
·
IF 19
Yuan Guan,Hongyu Li,Shufen Zhang,Wenbin Niu
Flexible self-healing thermal management devices are increasingly in demand due to their high flexibility, low driving voltage, and excellent stability of thermal property. In this paper, the design of mechanochromic self-healing thermal management devices is reported based on photonic vitrimer through self-healing dynamic covalent bond. A series of new photonic vitrimers i first prepared by dynamic disulfide covalent bond and PS@SiO 2 photonic crystals. The resulting photonic vitrimer exhibits bright structural colors, large tensile strain (>1000%), high mechanical strength (>10 MPa) and self-healing ability (>95% efficiency). More importantly, the structural color remains constant after 10000 stretching/releasing cycles, demonstrating excellent mechanical stability, creep-resistance, and durability. Taking advantage of the above features, a novel mechanochromic flexible wireless thermal management (MFW) device is developed by semi-embedding the photonic vitrimer in a thermally conductive carbon nanotube film and then integrating it with a Bluetooth module and a control chip. Interestingly, the MFW device exhibits mechanochromic property, fast thermal response, low driving voltage (103 °C, at 3 V), and precise temperature control. Notably, the device even remains electrothermal performance (105 °C) after self-healing. This work provides new insight into the self-healing photonic materials, and the device shows promising applications in wearable electronics, vitro physiotherapy, and personal heating.
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高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 6
·期 8
·1068-1078
·
IF 8.683
Yulei Gao,Zhou Deng,Fenfen Wang,Pingchuan Sun
Pure organic polymer materials exhibiting room-temperature phosphorescence (RTP) are highly desired for optoelectronic and biomedical applications. Covalent bonding of phosphors into a polymer matrix has been found to be successful in constructing efficient RTP materials owing to the substantial roles of the polymer matrix in restricting the molecular motion of phosphors and activating RTP emissions, thus fabricating new covalently crosslinked high-performance RTP materials is of great significance. Herein, a reasonable RTP system is constructed by covalently linking the phosphor (BF2epo) into an epoxy-based vitrimer network to obtain fluorescence and RTP double emissions. The 3D crosslinked polymer network structure restricts the molecular motion of BF2epo, depresses nonradiative transition and shields quenchers effectively. By altering the content of BF2epo, polychromatic photoluminescence and long phosphorescence lifetime are achieved under air conditions. The RTP emission intensity of this vitrimer material can respond to two different stimuli of ammonia and temperature, making it possible to work as sensors with good mechanical properties. Furthermore, the topology rearrangement of a dynamically crosslinked network structure endows this dual emission vitrimer with potential prospects in applications such as device fabrication and processing because of the advantages of excellent thermomechanical properties, high thermal stability, and self-repairing properties.
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高影响因子
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