POLYMER TESTING
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2023
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IF 5.1
Yuan Nie,Mei Li,Shouhai Li,Mingtao Lin,Na Yao,Tianxiang Deng,Xiao Feng,Xiaohua Yang,Haiyang Ding,Lina Xu
The exploration of novel bio-based functional polymers has high application value and confirms to sustainable development strategies following the increasing shortage of fossil resources. In this research, several different recyclable bio-based dynamic covalent polymer networks (DCPNs) containing dynamic Diels-Alder bonds from vegetable oil and furan were designed and fabricated via a simple preparation process. The reprocessability, shape memory, molecular structures, thermal properties and mechanical properties of the DCPNs were all investigated. 1 H nuclear magnetic resonance ( 1 H-NMR) and Fourier transform infrared spectroscopy (FTIR) analysises demonstrated the target reactive products were all successfully synthesized. Variable-temperature FTIR and differential scanning calorimetry revealed the changing rule of dynamic Diels-Alder bond molecular structures with temperature. The DCPNs possess controllable tensile properties including superior ductility and certain rigidity via adjusting fatty chain component, which is in accordance with the result of dynamic mechanical analysis. Thermal gravimetric analysis demonstrated the DCPNs had excellent thermostability, and the main peak decomposition temperatures were all above 460 °C. The nature of the dynamic Diels-Alder bonds could make shattered DCPNs be reprocessed multiple times under relatively mild conditions. The DCPNs displayed certain shape memory properties, and the shape fixation and recovery ratio at the last two cycles were kept above 95.53% and 84.58%, respectively. This work will help with the development on this kind of bio-based polymers containing dynamic Diels-Alder covalent bonds.
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PROGRESS IN ORGANIC COATINGS
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2013
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IF 1.848
Yugang Huang,Laixing Pang,Hongliang Wang,Rong Zhong,Zhaohua Zeng,Jianwen Yang
UV-curable tung oil based resins of GMA-PCDMAT and GMA-ICDMAT were synthesized via Diels–Alder reaction with maleic anhydride (MA), subsequent nonisocyanate polyurethane (NIPU) reaction with piperazine-1,4-dicarboxylic acid bis-(2-hydroxy-ethyl) ester (PCD) or isophoronediamine-1,4-dicarboxylic acid bis-(2-hydroxy-ethyl) ester (ICD) and acrylated modification with glycidyl methacrylate (GMA). The final chemical structures of GMA-PCDMAT and GMA-ICDMAT depend on the feeding ratio of MA, tung oil, PCD (or ICD) and GMA. Results of 1 H NMR and FTIR revealed that the targeted tung oil-based resins were successfully obtained. All the obtained resins had broad molecular weight distributions. UV-curing kinetic and thermal properties were respectively revealed by photo-DSC, DSC and TG. Higher concentration of C C bonds led to faster curing rate but lower final conversion of C C bonds. All the cured films had two glass transitions, one in the range of 8–10 °C and another in the range of 46–48 °C. All the cured films possessed excellent thermal stability, and the start temperature of decomposition ( T sta ) was as high as 350 °C, implying that they can be used for UV coatings for the substrates with high-temperature resistance. The introduction of structure of NIPU is helpful to enhance adhesion of the cured films with substrates.
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POLYMER DEGRADATION AND STABILITY
·
2017
·
IF 3.386
Xue Dong,Rong-Tao Duan,Yan-Peng Ni,Zhi-Jie Cao,Li Chen,Yu-Zhong Wang
Retro-Diels-Alder reaction (rDA) has been widely used as a common modification approach for expanding functional applications of polymers. Especially, it has become an effective method of current cross-linking chemistry . With the goal of designing a cross-linkable PET-based copolyester toward flame retardancy and anti-dripping during combustion, dimethyl 5-(1,3-dioxo-3a,4,7,7a-tetrahydro-1 H -4,7-methanoisoindol-2(3 H )-yl) isophthalate (DMTMI) was incorporated as the functional co-monomer into PET chains via random transesterification polycondensation . Thermogravimetry-differential scanning calorimetry (TG-DSC) and rheological studies demonstrated the existence of cross-linking behavior at high temperature. By controlling the co-monomer content, expected flame retardancy was obtained, as illustrated by the results from the limiting oxygen index (LOI) and cone calorimetry. Furthermore, LOI values increased firstly and then decreased with the content of DMTMI increased, which was related to the existence of rDA reaction, and further proposed that a competitive relationship between the release of inflammable cyclopentadiene during rDA reaction and cross-linking behavior occurred in combustion. The hypothesis was verified through pyrolysis-gas chromatograph-mass spectrometry (Py-GC-MS).
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CARBON
·
2020
·
IF 8.821
Meng Zhou,Qiming Yan,Qi Fu,Heqing Fu
The combination of microwave absorption performance and self-healing function is of great practical significance. In this paper, first, ZnO@MWCNTs nanoparticle is prepared by loading Zinc oxide (ZnO) on the surface of the multiwalled carbon nanotubes (MWCNTs) as microwave absorbers. Then, the thermoreversible self-healing DA-PDMS is prepared by using polydimethylsiloxane (PDMS) as raw material based on Diels-Alder (DA) reaction. Finally, a kind of novel multifunctional ZnO@MWCNTs/DA-PDMS nanocomposite with self-healing and microwave absorption properties is synthesized with the addition of ZnO@MWCNTs nanoparticle. When the cracked ZnO@MWCNTs/DA-PDMS nanocomposite is maintained at 120 °C for 10 min, it can recover more than 90% of the original mechanical strength . Even after three healing cycles, the ZnO@MWCNTs/DA-PDMS nanocomposite also displays excellent healing efficiency (about 90%). On the other hand, when the content of ZnO@MWCNTs nanoparticle is 10 wt%, ZnO@MWCNTs/DA-PDMS nanocomposite exhibits an effective absorption bandwidth from 8.2 to 12.4 GHz (full X-band) at a thickness of 3 mm and the minimum reflection loss of −20.1 dB. Even after the 3rd healing cycle, the minimum reflection loss of the healed samples can still maintain −20.0 dB at a thickness of 3 mm. ZnO@MWCNTs/DA-PDMS nanocomposite will have good development prospect in the field of intelligence and microwave absorption materials .
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INORGANIC CHEMISTRY
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2025
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IF 4.7
Hui-Mei Shan,Lin Li,Qian Wang,Li-Ping Xu
Supramolecular metal–organic cages (MOCs) have gained attention as versatile catalytic platforms due to their self-assembled architectures and well-defined cavities, which mimic enzyme active sites and enable spatial confinement. This confinement modulates the reaction pathways and enhances the catalytic performance. Recent studies highlight their catalytic potential in various organic transformations, but the factors governing the MOC-catalyzed reactions remain incompletely understood. This work builds on prior computational studies of Diels–Alder reactions catalyzed by palladium-based MOCs, showing that the common view of transition-state stabilization via π–π interactions is not valid. Instead, we find that π–π interactions between the substrate and the ligands destabilize the transition state. Additionally, theoretical studies of regioselectivity, validated experimentally, suggest that substrate encapsulation efficiency is key to determining reaction selectivity. These findings provide new insights into the mechanisms of MOC-catalyzed reactions.
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PubMed
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
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2025
·
IF 3.6
Shuaikang Zhou,Siyi Qin,Xifang Zhang,Ying Song,Yuanfei Zhang
A Pd-catalyzed protocol that provides efficient access to acyclic 1,2-dioxygenated dienes has been established. The installation of the bifunctional carbonate electrofuge to the diene cores enabled such dienes to undergo a regioselective decarboxylative Diels–Alder cycloaddition/aromatization reaction, affording diverse synthetic challenging multisubstituted phenols with ease.
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高影响因子
POLYMER
·
2017
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IF 3.684
Libang Feng,Zhengyang Yu,Yaohui Bian,Junshan Lu,Xueting Shi,Changsheng Chai
Cracks generated in materials affect comprehensive performance and shorten service life of materials. The problem is expected to be resolved by endowing materials with self-healing property. Herein, a new thermoplastic polyurethane with excellent self-healing performance (PU-DA) has been developed, while the self-healing behavior is investigated by qualitative observation and quantitative measuring comparatively. Results reveal that PU-DA exhibits excellent thermal reversibility due to incorporated Diels-Alder (DA) bonds, and cracks in polyurethane films can be repaired by dual actions of thermo-reversible DA reaction and thermal movement of molecular chains . DA bond and its thermal reversibility contribute much to the recovery of the mechanical property while the thermal movement effect of molecular chains acts as an auxiliary recovering force which accelerates the whole healing process. The self-healing behavior of PU-DAs from diverse soft segments and different -NCO/-OH values further confirms that the excellent self-healing performance is grounded on combined actions indeed. Additionally, the self-healing polyurethane presents outstanding reprocessing performance, and which makes it possible of recycling waste polyurethanes. This study enables the re-demonstration of general points about DA thermal reversibility already known, as well as presentation of link between self-healing capability and thermal reversibility along with thermal movement.
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PROGRESS IN ORGANIC COATINGS
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2022
·
IF 6.206
Ying Cao,Xiaoyu Wang,Jianhua Wu,Yiting Xu,Jean-Francois Gerard,Liuyin Jiang,Birong Zeng,Lizong Dai
The coatings which are able to protect the metal from being corroded by the medium in their service life while are easy to be removed when the regular maintenances and refurbishment of the coatings are carried out are in high demand. However, the relevant researches are few. In this article, a novel hexagonal boron nitride/epoxy anti-corrosive coating with self-healing, removable and recycled abilities were designed. These coatings which were totally dynamic cross-linked were synthesized by the Diels-Alder reaction between a modified hexagonal boron nitride with maleimide functional groups and epoxy containing both furan and epoxide functional groups. The structures of the epoxy composites were fully characterized. Their thermal properties, self-healing abilities, and removeable properties were also explored. The systematic study on the anti-corrosive properties of the coatings was carried out. An inhibition efficiency of 97.2 % could be realized by the sample of m-hBN-OH/epoxy 98 – 2 , in which 2 % of the cross-linking degree was provided by the functional hBN fillers. All the research results revealed that this novel coating could serve as the long durable anti-corrosive material in its service life while was easy to be removed when the regular refurbishment was conducted.
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Polymers
·
2021
·Vol. 13
·期 23
·4155
·
IF 4.329
Lijuan Chen,Xisen Cai,Zhonghui Sun,Baohua Zhang,Yu Bao,Zhenbang Liu,Dongxue Han,Li Niu
Thermally reversible self-healing polymer (SHP) electrolyte membranes are obtained by Diels-Alder cycloaddition and electrolyte embedding. The SHP electrolytes membranes are found to display high ionic conductivity, suitable flexibility, remarkable mechanical properties and self-healing ability. The decomposition potential of the SHP electrolyte membrane is about 4.8 V (vs. Li/Li+) and it possesses excellent electrochemical stability, better than that of the commercial PE film which is only stable up to 4.5 V (vs. Li/Li+). TGA results show that the SHP electrolyte membrane is thermally stable up to 280 °C in a nitrogen atmosphere. When the SHP electrolyte membrane is used as a separator in a lithium-ion battery with an LCO-based cathode, the SHP membrane achieved excellent rate capability and stable cycling for over 100 cycles, and the specific discharge capacity could be almost fully recovered after self-healing. Furthermore, the electrolyte membrane exhibits excellent electrochemical performance, suggesting its potential for application in lithium-ion batteries as separator material.
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Polymers
·
2018
·Vol. 10
·期 9
·949
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IF 2.935
Gang Wang,Xiaodong Cao,Hua Dong,Lei Zeng,Chenxi Yu,Xiaofeng Chen
A hyaluronic acid (HA) based injectable hydrogel with gradually increasing mechanical properties was synthesized via photo-crosslinking reaction and thermal-induced Diels-Alder (DA) reaction. The injectable hydrogel can quickly gelate within 30 s by photo-crosslinking of HA-furan under the catalysis of lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP). This injectable property is beneficial to keep the encapsulated cell activity and convenient for clinical operation. And the mechanical properties can be control from 4.86 to 10.66 kPa by exposure time. Then, the thermal-induced DA click chemistry further occurs between furan groups and maleimide groups which gradually promoted the crosslinking density of the injectable hydrogel. The mechanical properties of the injectable hydrogel can be promoted to 21 kPa. ATDC-5 cells were successfully encapsulated in the injectable hydrogel and showed good activity. All the results suggested that the injectable hydrogel with gradually increasing mechanical properties formed by photo-crosslinking reaction and thermal-induced DA reaction has a good prospect of application in cartilage tissue engineering.Keywords:injectable hydrogel;photo-crosslinking reaction;DA click chemistry;cartilage tissue engineering
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高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2026
·
IF 5.4
Yue Xiaopeng,Liu Hao,Ji Yu,Guan Lixiang,Lu Hailong
Modification of sebacic acid and citric acid with furfurylamine produces furfurylated sebacic acid (FS) and furfurylated citric acid (FC). Successfully constructs a high-performance polymer. • FS and FC increase cross-linking sites for DA reactions and elevate cross-linking density. • Raised cross-linking density strengthens synergistic interactions between FS/FC, lignin and flame retardants. In this study, two kinds of furan-terminated small molecules (FS and FC) were synthesized via amidation reactions between furfurylamine and polyacids (sebacic acid or citric acid), respectively, and were incorporated into the furan-functionalized epoxidized soybean oil (FE)/furan-terminated lignin (FL) thermo-reversible polymer network via Diels-Alder (DA) reaction to regulate the crosslinking density of the network. With the incorporation of DOPO-based reactive flame retardants (DE and DF), a structural optimized thermo-reversible/flame-retardant polymer with a reinforced network was fabricated. By introducing linear two-arm (FS) or branched three-arm (FC) structures, especially FC, the crosslinking density of the networks was significantly improved. As a result, the tensile strength, fracture toughness (KIC), and self-healing properties of the polymer were synchronously improved. The increased crosslinking density also enhanced the synergistic effect between FS/FC, lignin, and flame retardants, leading to improved char-forming ability and flame-retardant efficiency. The limiting oxygen index of 75FE/5FL/10FC/5DE/5DF reached 28.9% with the addition of only 5 wt% FL, enabling it to pass the UL-94 V-0 flammability rating. Compared with 100FE, this formulation exhibited reductions in total smoke production (TSP), smoke production rate (SPR), total heat release (THR), and peak heat release rate (pHRR) by 31.4%, 44.4%, 18.06%, and 21.67%, respectively. Additionally, it achieved a self-healing efficiency of 85.20% and retained 71% of its tensile strength after three reprocessing cycles. Through the aforementioned strategy, this work successfully overcomes the common trade-off among mechanical properties, self-healing efficiency, and flame retardancy in biobased dynamic polymers. It offers a practical example for developing sustainable, intelligent advanced polymeric materials for future applications. Download: Download high-res image (171KB) Download: Download full-size image
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COMPOSITES PART B-ENGINEERING
·
2026
·
IF 14
Guanjun Liu,Meiling Yan,Conghao Jiang,Ying Liu,Zhen Tian,Fan Yang,Rongguo Wang
Hydrogen barrier materials capable of retaining effective barrier performance after mechanical damage are highly desirable for hydrogen storage and transportation applications. Here, we report a functionalized graphene oxide reinforced polyurethane nanocomposite containing Diels-Alder (DA) bonds, denoted as fGO/PU-DA, in which dynamic DA linkages were incorporated into both the polymer matrix and the nanofiller-matrix interface. The 5 wt% fGO/PU-DA nanocomposite achieved a tensile strength of 9.8 MPa, corresponding to a 75% increase over neat PU-DA, while maintaining a favorable balance between strength and ductility. After cut-healing treatment, the nanocomposite recovered nearly all of its tensile strength, whereas its elongation at break and toughness exceeded their original values even after three damage-healing cycles, highlighting the contribution of interfacial DA bonds to healing efficiency. The hydrogen permeability coefficient decreased from 2.4 × 10 −12 for neat PU-DA to 8.6 × 10 −13 cm 3 cm cm −2 ·s −1 Pa −1 for the 5 wt% fGO/PU-DA nanocomposite, corresponding to a reduction of 64%. Even in the healed state, the permeability remained markedly lower than that of healed PU-DA, indicating a clear barrier advantage after macroscopic damage. Mechanistic analysis indicated that the enhanced barrier performance was diffusion-dominated and originated from interfacial confinement together with reduced cooperative segmental mobility. The material was further validated as a coating on polyamide 6 substrates, where the fGO/PU-DA layer also delivered improved hydrogen barrier performance. These results demonstrate that coupling matrix-level reversible reconstruction with interfacial dynamic DA bonding provides an effective route to polyurethane nanocomposites integrating self-healing capability, mechanical robustness, and superior hydrogen barrier performance.
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