INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2022
·Vol. 23
·期 16
·8833
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IF 6.208
Yang Feng,Zhuguang Nie,Panhong Deng,Liping Luo,Xingman Hu,Jie Su,Haiming Li,Xiaodong Fan,Shuhua Qi
An effective method was developed to improve the interfacial interaction between Mutiwalled carbon nanotubes (MWCNTs) and epoxy matrix. The performance of thermal conductivity and strength of the epoxy vitrimer were enhanced by polydopamine (PDA) coating. Polydopamine is a commonly used photothermal agent, which of course, was effective in modifying MWCNTs used in photoresponsive epoxy resin. The surface temperature of the epoxy composite with 3% MWCNTs@PDA fillers added increased from room temperature to 215 °C in 48 s. The metal–catechol coordination interactions formed between the catechol groups of PDA and Zn2+accelerated the stress relaxation of epoxy vitrimer. Moreover, the shape memory, repairing, and recycling of epoxy vitrimer were investigated. Therefore, dopamine coating is a multifunctional approach to enhance the performance of epoxy vitrimer.Keywords:dopamine;stress relaxation;vitrimer;shape memory polymer
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高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 46
·25356-25367
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IF 11.9
Ganggang Zhang,Chenchen Tian,Heying Chu,Jun Liu,Baochun Guo,Liqun Zhang
Reinforcement and cross-linking are two critical issues in the rubber industry. However, carbon black (CB) as the most dominant reinforcing filler is derived from fossil resource-derived chemicals. And currently adopted cross-linking strategies would result in difficulties in the recycling of end-of-life rubbers. Herein, lignin, the most abundant renewable aromatic polymer, was developed as an effective reinforcing filler of rubber. The butadiene–styrene–vinylpyridine rubber (VPR) was selected as the rubber matrix, and a facile and cost-effective strategy was provided to improve the compatibility and interfacial interaction between lignin and the non-polar rubber matrix. Based on the Zn2+–pyridine coordination between the pyridine groups in the VPR chains and phenoxy groups in the lignin molecules, the lignin particles could obtain fine dispersion in the rubber matrix, exhibiting an excellent reinforcing effect. Moreover, the pyridine groups in the VPR chains were developed as cross-linking points, and the VPR could be effectively cross-linked based on the chemical reaction between the pyridine group and alkyl halide, producing quaternized pyridine groups. Due to the existence of the exchange reaction via the C–N transalkylation of the quaternized pyridine groups, the lignin/VPR composites could show vitrimer-like properties and are endowed with good reprocessability at high temperatures. Additionally, due to the photothermal conversion capability of lignin, the lignin/VPR composites could exhibit good photothermal performance triggered by 808 nm near-infrared light, and further possess light-driven shape memory properties. Hence, we envisage that this work can provide an avenue to design and fabricate green, sustainable, and recyclable elastomer materials with lignin as a renewable bio-filler.
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COMPOSITES PART B-ENGINEERING
·
2020
·
IF 7.635
Hongwei Si,Lin Zhou,Yeping Wu,Lixian Song,Ming Kang,Xiuli Zhao,Mao Chen
With large quantities of waste carbon fiber reinforced polymer (CFRP) composites generated, the development of recycling routes for CFRP composites have been driven by both environmental and economic factors. Vitrimer materials provide exciting opportunities to recycle thermosets and CFRP composites, since they can be thermally reprocessed without losing their permanently cross-linked networks. However, the poor mechanical properties , additional catalyst and time-consuming recycling process still limit their applications. Herein, the authors proposed an epoxy vitrimer with high contents of exchangeable aromatic disulfide crosslinks to overcome these limitations. This epoxy vitrimer exhibited outstanding properties with the glass transition temperature (T g ) of 147 °C and the tensile strength of 63.1 MPa. Upon heating, it released the stress from deformation more rapidly without any catalyst, resulting from the high contents of disulfide crosslinks in the network. Meanwhile, the networks exhibited excellent reprocessability and were more readily degraded by thiols. Moreover, this epoxy was applied as matrix to prepare recyclable CFRP composites. By dissolving the epoxy matrix efficiently, the carbon fibers embedded were recycled rapidly and they still exhibited outstanding mechanical properties when being reused to form CFRP composites. Results from this study may promote the wide development of cost-efficient recyclable composites in automotive, wind power and aeronautical industries .
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GREEN CHEMISTRY
·
2019
·Vol. 21
·期 6
·1484-1497
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IF 9.405
Sheng Wang,Songqi Ma,Qiong Li,Xiwei Xu,Binbo Wang,Wangchao Yuan,Shenghua Zhou,Shusen You,Jin Zhu
Epoxy resins have been widely used in several materials including carbon fiber composites; however, they are arduous to recycle. In this study, for the first time, a Schiff base epoxy thermoset combining excellent recyclability and high performance was facilely prepared from a synthesized formyl group-containing vanillin-based monoepoxide and a diamine via in situ formation of the Schiff base structure and epoxy network. The chemical structure of the monoepoxide and its cross-linked network were characterized in detail. In addition, the thermal and mechanical properties, recyclability of the thermoset and its application in carbon fiber composite were systematically investigated. The results showed that the thermoset possessed a similar glass transition temperature of 172 °C, a tensile strength of 81 MPa and a modulus of 2112 MPa, and higher thermal stability with the degradation temperature for 5% weight loss of 323 °C and elongation at break of 15% in comparison with a bisphenol A epoxy resin. Moreover, it exhibited superior reprocessing recyclability due to the vitrimer or CAN nature of its Schiff base network. Furthermore, it could also be completely degraded under mild acidic conditions, leading to the quick and nondestructive recycling of its carbon fiber composite.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Qingyun Zhao,Xiaohui Liu,Shuo Deng,Xianghong Zheng,Birong Zeng,Xinyu Liu,Yiting Xu,Conghui Yuan,Lizong Dai
A composited flame-retardant phosphorus-containing polyimine vitrimer films (Ionic-PIs) were synthesized by using ionic liquid BMIM∙PF 6 containing flame retardant elements N, P and F as the regulator. The effects of the addition amount of BMIM∙PF 6 on the mechanical properties, degradation, recycling, and flame retardancy were investigated. Compared to intrinsically phosphorus-containing polyimine film (PI), the composited Ionic-PIs exhibited better mechanical strength and toughness. Hydrogen bonding interactions between BMIM∙PF 6 and polyimine network greatly increased Ionic-PI’s mechanical strength at a low addition of 1 wt%, and the microphase separation caused by the aggregation of BMIM∙PF 6 drastically enhanced their toughness as the addition increased. Ionic-PIs exhibited excellent reprocessability at 85 °C and degradable recyclability under acidic conditions. In addition, due to the synergistic effect of condensed-phase and gas-phase flame-retardant mechanisms, the Ionic-PIs possessed good flame retardancy with LOI above 27 % and a UL-94 test reaching VTM-0 grade, which was important for the high-fire safety of polyimine vitrimer. This work is helpful to provide a simple and feasible strategy to modulate the comprehensive properties of cross-linked polyimine vitrimer film and to expand their applications in many fields.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2026
·
IF 3.9
Shichang Wang,Zhengzhuo Li,Yuan Ji,Hong Wu,Shaoyun Guo
The incorporation of dynamic covalent networks into epoxy resins is an effective strategy to overcome their inherent limitations of nonreprocessability and nondegradability, leading to a class of materials known as epoxy vitrimers. Despite recent progress in achieving rapid reprocessability and degradability, epoxy vitrimers still face challenges, including inadequate mechanical properties and the prevalent use of the toxic precursor bisphenol A diglycidyl ether (BADGE). Herein, we report a one-pot synthesis of a biobased epoxy vitrimer using vanillin, diamino-functionalized phenylenediboronic ester (DPDBE), and polyether amine (PEA), which incorporates dual dynamic covalent bonds of the imine and boronic ester. The resulting vitrimer exhibits a remarkable combination of high mechanical strength and good toughness, achieving a tensile strength of 73 MPa with an elongation at break of 23%. This excellent mechanical performance is attributed to the molecular design: the conjugation between the imine bonds and benzene rings, the rigidity of the boronic ester five-membered rings, and the flexible ether bonds and long methylene chains from PEA. Furthermore, the synergistic effect between the imine and boronate ester bonds enables an exceptionally low activation energy (Ea) of 58.1 kJ/mol for the bond exchange reactions, resulting in rapid reprocessability within 5 min and complete degradation within 30 min. This work presents a promising strategy for developing high-performance, environmentally friendly epoxy vitrimers from sustainable resources.
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INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Zihao Feng,Yuhan Huang,Jiahui Chen,Haichuan Gao,Jiatian Zhu,Shengdong Mu,Wenjun Li,Wei Zhao,Bailiang Xue,Yonghao Ni
Distiller’s grains (DG) are a major biomass waste product in the ethanol and brewing industries, and have shown great potential as fillers for polymer composites. However, combining DG with polymer matrixes using traditional method often involves tedious pre-modification of DG and/or the use of costly coupling agents, significantly increasing the preparation cost of the final composite materials. In this study, we present an environmentally friendly approach for preparing a new type of green composite, termed distiller’s grains/epoxy vitrimer hybrid materials (EV@DG). This method eliminates the need for laborious pre-modifications of DG, as well as the use of solvents and coupling agents. The resulting EV@DG hybrid materials exhibit superior mechanical properties—approximately 90 % increase in tensile strength and 400 % increase in Young’s modulus—along with high thermal stability (T d,max of 357.63°C) and excellent reprocessability. Moreover, the EV@DGs demonstrate impressive photothermal conversion capabilities, positioning them as promising candidates for the fabrication of solar-thermal-electric generator.
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COMPOSITES PART B-ENGINEERING
·
2026
·
IF 14
Hao-Jie Shi,Hao-Xin Niu,Yu Li,Yuan Hu,Xin Wang
The tensile and impact strengths of CNEP were 35.81% and 58.02% higher than DGEBA/DDM, respectively. • PNEP-25 wt% had a LOI of 30.5% and achieved UL-94 V-0 rating. • CNEP exhibited excellent controllable degradation, self-healing and transparency. The application scope of epoxy resin, one of the most extensively utilized engineering materials, is notably restricted by limitations such as inherent flammability, brittleness, and non-degradability. Herein, two novel epoxy curing agents (BTAP and DPO-BTAP) were synthesized and reacted with DGEBA to prepare a series of novel vitrimer materials (CNEP and PNEP-xwt%, where x = 15, 20, and 25). The tensile strength of CNEP was 64.1 MPa, and the impact strength was 25.6 kJ/m 2 , which were 35.8% and 58.0% greater than those of DGEBA/DDM, respectively, indicating a combination of rigidity and flexibility. TGA analysis revealed that PENP-25 wt% had residual char contents of 2.9 wt% and 24.6 wt% in air and N 2 , respectively. PNEP-25 wt% had a limiting oxygen index (LOI) of 30.5% and achieved a UL-94 V-0 rating. Its peak heat release rate (PHRR) and total heat release (THR) decreased to 567 kW/m 2 and 45.96 MJ/m 2 , respectively, representing decreases of 56.9% and 39.7% compared with those of DGEBA/DDM. CNEP exhibited a relaxation time of 314 s at 175 °C, demonstrating good controllable degradation, self-healing properties, and transparency. This new vitrimer may represent a new generation of high-fire safety and degradable high-performance engineering materials. Download: Download high-res image (449KB) Download: Download full-size image
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Chuanyin Xiong,Tianxu Wang,Yongkang Zhang,Chao Duan,Zhao Zhang,Qiusheng Zhou,Qing Xiong,Mengjie Zhao,Bo Wang,Yonghao Ni
With the continuous improvement of living standards and advancements in science and technology, composite materials with multiple functionalities are gaining high practical value in modern society. In this paper, we present a multifunctional conductive paper-based composite with electromagnetic (EMI) shielding, sensing, Joule heating, and antimicrobial properties. The composite is prepared by growing metallic silver nanoparticles inside the cellulose paper (CP) modified with polydopamine (PDA). The resulting CP@PDA@Ag (CPPA) composite has high conductivity and EMI shielding properties. Furthermore, CPPA composites demonstrate exceptional sensing, Joule heating, and antimicrobial properties. In addition, Vitrimer, a polymer with excellent cross-linked network structure, is introduced into CPPA composites to obtain CPPA-V intelligent electromagnetic shielding materials with shape memory function. These excellent properties show that the prepared multifunctional intelligent composite has exceptional EMI shielding, sensing, Joule heating, and antibacterial and shape memory properties. In short, this multifunctional intelligent composite material has great application prospects in flexible wearable electronics.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2023
·Vol. 224
·期 14
·2300042
·
IF 2.5
Yang Xiong,Lili Liu,Chengyao Hu,Junxiao Yang,Yawen Huang
Ultra-low dielectric foams (ULDFs) have found important use in antennas and wave transparent devices. However, the controlled preparation of ULDFs is still a big challenge. In this work, a boronic ester bond-assisted hot-pressing/salt-leaching (BHS) method is proposed to generate interconnected pore structure with tunable porosity and performance. In detail, styrene resin vitrimer is prepared with boronic ester cross-linked network (BESR) which possessed low dielectric constant of 2.70, high modulus of 385 MPa, and reprocessability. BESR vitrimer exhibited drastically enhanced processability at the temperature > T v (160 °C). Thanks to this unique feature, BESR vitrimer foams can be fabricated by hot-pressing with salt particles followed by salt leaching. Such vitrimer foams exhibited advantageous pore-forming processability, fabrication efficiency, and pore stability over conventional polymeric foams. The low extreme of dielectric constant can reach 1.60. Furthermore, owing to interconnected pore structure, superhydrophobic foam (water contact angel (CA) ≈ 154°) is facilely fabricated on the basis of BESR to afford anti-icing performance. The BESR foam can maintain its superhydrophobicity underwater flow impacting at 10 kPa pressure, showing advantageous high durability. BESR foams also have good recyclability and would be potentially applied in recyclable antennas.
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CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Kuiling Wei,Xuejuan Cao,Boming Tang,Yan Wu,Tianqiang Jiang
Thermosetting polymers , commonly used to improve asphalt properties, bring excellent pavement performance , but also pose significant challenges to the healing and recyclability of their modified asphalts after long-term service. An effective approach involves introducing dynamic bonds into the crosslinking networks to synthesize Vitrimer-modified asphalts with self-healing response. Due to the splendid mechanical properties, high elasticity, flexibility and easily controllable cross-linked structure of polyurethane , a novel castor oil-based polyurethane Vitrimer modified asphalt with disulfide bonds and Diels-Alder reactions was developed. Based on the prepared castor oil-based polyurethane Vitrimer (C-PUV, composed of components A and B) and its modified asphalts (C-PUVAs), a comprehensive study was conducted on the crosslinking density , mechanical properties, thermal stability, viscosity , compatibility, rheological properties, and self-healing behavior. The results indicated that C-PUVAs (C-PUVA1/C-PUVA2/C-PUVA3/C-PUVA4) exhibited sufficient retention times for viscosity, uniform phase distribution, and good high-temperature performance. The damaged C-PUVAs achieved a mechanical strength recovery rate more than 75 % after the first cycle of self-healing at 80 ℃ and 0.3 MPa. Furthermore, the crosslinking density of C-PUV was regulated by the segment length of component B. As the crosslinking density increased, C-PUV and C-PUVAs obtained higher mechanical strength while sacrificing part of self-healing efficiency. The mechanism is that increased crosslinking density altered the gel point distributions of the reversible crosslinked networks, resulting in a longer relaxation time and higher activation energy . In conclusion, the above findings provided valuable insights for developing bio-based polyurethane Vitrimer modified asphalts, and endosing thermosetting polymer modified asphalts with self-healing and recyclable properties.
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ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Yajie Zhang,Li Yuan,Guozheng Liang,Aijuan Gu
A bio-based tetrafunctional epoxy monomer containing a dicyclo diacetal linkage was successfully synthesized via acetalization of protocatechualdehyde (PCA) with erythritol, followed by a reaction with bioderived epichlorohydrin. The epoxy monomer exhibits good reactivity with glutaric anhydride in the presence of a zinc(II) acetylacetonate (ZAA) catalyst and can be cured using a medium-temperature procedure. The prepared epoxy vitrimer (DGZ) systems exhibit excellent mechanical and thermal properties resulting from the rigid dicyclo diacetal and aromatic structures and the high conversion of epoxy groups (αepoxy group). When the ZAA content is 2.5%, DGZ has optimal integrated mechanical properties, and its impact strength, tensile strength, and flexural strength can reach 20 kJ/m2, 60 MPa, and 119 MPa, respectively, which can be compared with those of the commercial bisphenol A epoxy resin cured with a high-temperature procedure. DGZ systems have a good glass-transition temperature (Tg) of 111–117 °C. The broad glass transition endows DGZ with a good shape memory effect. The introduction of dynamic ester bonds in DGZ brings good self-healing ability, welding ability, and rapid stress relaxation. The self-healing efficiency of the scratches on the surface of DGZ can reach ∼100% at 200 °C. Owing to the existence of dicyclo diacetal linkages, DGZ can be completely degraded in 0.1 and 1 M HCl solutions at 25–80 °C. DGZ also has good dielectric properties due to the rigid dicyclo diacetal and aromatic structures, as well as a high αepoxy group.
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