PROGRESS IN ORGANIC COATINGS
·
2016
·
IF 2.632
Xiaoxue Ke,Hongbo Liang,Lei Xiong,Shengmei Huang,Min Zhu
A novel polyurethane resin containing acrylate function and Diels-Alder (DA) structure was synthesized, with potential thermal reversibility and UV curable properties. The UV curing process was monitored by Fourier transform infrared spectroscopy (FTIR), which indicated that the DA structure was stable during curing process and the final acrylate C C conversion is 82.5%. The cured film exhibited good repeatedly thermal reversibility. The retro-Diels-Alder (rDA) reaction of the cured film occurred at temperatures higher than 85.5 °C and was obviously accelerated by increasing temperature, which was confirmed by the results of FTIR, differential scanning calorimeter (DSC) and dynamic thermomechanical analysis (DMA). The cured film displayed acceptable thermal stability up to 278.3 °C according to the thermal gravimetric analysis (TGA) results. Finally, a cured film with excellent physical properties was obtained.
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ACTA PHARMACOLOGICA SINICA
·
2020
·Vol. 42
·期 5
·780-790
·
IF 5.064
Shu Yu-han,Yuan Hua-hua,Xu Meng-ting,Hong Ye-ting,Gao Cheng-cheng,Wu Zhi-pan,Han Hao-te,Sun Xin,Gao Rui-lan,Yang Si-fu,Li Shou-xin,Tian Jing-kui,Zhang Jian-bin
Guangsangon E (GSE) is a novel Diels–Alder adduct isolated from leaves of Morus alba L, a traditional Chinese medicine widely applied in respiratory diseases. It is reported that GSE has cytotoxic effect on cancer cells. In our research, we investigated its anticancer effect on respiratory cancer and revealed that GSE induces autophagy and apoptosis in lung and nasopharyngeal cancer cells. We first observed that GSE inhibits cell proliferation and induces apoptosis in A549 and CNE1 cells. Meanwhile, the upregulation of autophagosome marker LC3 and increased formation of GFP–LC3 puncta demonstrates the induction of autophagy in GSE-treated cells. Moreover, GSE increases the autophagy flux by enhancing lysosomal activity and the fusion of autophagosomes and lysosomes. Next, we investigated that endoplasmic reticulum (ER) stress is involved in autophagy induction by GSE. GSE activates the ER stress through reactive oxygen species (ROS) accumulation, which can be blocked by ROS scavenger NAC. Finally, inhibition of autophagy attenuates GSE-caused cell death, termed as “autophagy-mediated cell death.” Taken together, we revealed the molecular mechanism of GSE against respiratory cancer, which demonstrates great potential of GSE in the treatment of representative cancer.
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PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2014
·
IF 2.302
Yugang Huang,Guodong Ye,Jianwen Yang
Tung oil-inspired UV-curable resins for coating materials were synthesized by Diels–Alder reaction between tung oil and maleic anhydride (MA), then subsequent reaction with 2-hydroxyethyl acrylate (HEA) or pentaerythritol triacrylate (PETA), and final modification with glycidyl methacrylate (GMA). Structures of the obtained resins designated as HG-MAT and PG-MAT mainly depend on feeding ratio of MA, tung oil, and HEA (or PETA). Results of both 1 H NMR and FTIR revealed that the targeted resins were successfully prepared. The resins had broad molecular weight distributions with PDI from 1.70 to 2.20 due to the complicated side reactions. UV-curing kinetics of the resins was studied by Photo-DSC, and thermal properties of their cured films were investigated by DSC and TGA. Higher content of acrylate C C bonds led to faster curing rate but lower conversion of C C bond. The cured films had a glass transitions in the range of 40–52 °C. All the cured films possessed excellent thermal stability, and the start temperature of decomposition ( T sta ) was above 350 °C.
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CHINESE CHEMICAL LETTERS
·
2016
·
IF 1.947
Dong-Hang Yin,Wei Liu,Zhi-Xiang Wang,Xin Huang,Jing Zhang,De-Chun Huang
The direct three-component aza-Diels–Alder reaction was conducted with lipase as a catalyst for the first time. Under the optimized conditions, the aza-Diels–Alder reaction catalyzed by lipase from Candida sp. 99–125 provided the products in moderate to excellent yields. Meanwhile, the endo / exo ratio reached up to 88:12.
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ACS Catalysis
·
2025
·
IF 13.1
Yong Tang,Yongqi Zeng,Chunyu Wang,Zhi Wang,Danning Zhao,Chuang Du,Fengxi Li,Lei Wang
The enzymatic Diels–Alder reaction presents an environmentally appealing strategy for synthesizing chiral norbornene scaffolds. In this study, an artificial Diels–Alderase was constructed by incorporating a biotinylated Cu-phenanthroline cofactor (5-NH2Phen-biotin*Cu(NO3)2) into streptavidin and optimizing the enzyme through genetic engineering. The S112D variant of this artificial Diels–Alderase exhibited commendable catalytic performance, facilitating highly enantio- and regioselective Diels–Alder reactions. Employing this method, we synthesized a series of norbornene pyridones with broad substrate scopes and good functional group tolerance under mild conditions, achieving high yields along with good enantio- and regioselectivities. Molecular dynamics (MD) simulations provided insights into the critical complex intermediates involved in the proposed reaction mechanism and clarified the interactions between the Diels–Alderase and its substrates, revealing the structural basis for the generation of the predominant norbornenepyridone conformation and the enhanced selectivity observed with the S112D mutant. Furthermore, quantum mechanics/molecular mechanics (QM/MM) calculations analyzed the reaction energy barriers of possible transition states, elucidating the reason for the formation of the target product from an energetic perspective.
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JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 3
·1-9
·
IF 2.8
Li Wanrong,Zhan Qingyan,Yang Po
This work aims to generate maleimides to polymers via Diels–Alder reaction and ring-opening metathesis polymerization (ROMP). Maleimides were converted to adducts through Diels–Alder reactions by reacting with cyclopentadiene or furan, then these adducts were generated to the corresponding polymers via ring-opening metathesis polymerization. The chemical structures of adducts were confirmed by 1 H NMR, FTIR and elemental analysis. After investigating the polymerization behaviors and properties, we found that the adducts could be converted into polymers via ROMP and affording polymers exhibited excellent performance. For example, the glass transition temperature of PBMC is 252 °C, 5% and 10% weight loss temperatures are successively 381 °C and 475 °C, and the relative dielectric constant ( D k ) and dissipation (D f ) at 1 Hz and 1 MHz are respectively 3.41 and 0.006, 3.35 and 0.020. Moreover, the adducts can be used to enhance other ROMP-derived polymers as the comonomers. We believe these may help researchers design and explore novel maleimides polymers and copolymers with promising properties.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Ze Pu Wang,Wen Hong Ruan,Min Zhi Rong,Ming Qiu Zhang
To tackle the challenge of producing highly filled polymer composites using the traditional injection molding technique, which is characterized by the fairly high melt viscosity that makes mold filling difficult, the authors propose a solution based on dynamic covalent chemistry. As demonstrated by the proof-of-concept experiments, the 4-arm star-shaped polycaprolactone (PCL) oligomers and microcrystalline cellulose (MCC) are crosslinked by the reversible Diels-Alder (DA) bonds. The flowability of the compounds greatly decreases due to the dissociation of the intercomponent DA bonds at the retro-reaction temperature, and the networked architecture is reconstructed during cooling as a result of the forward DA reaction. Consequently, the high-loading MCC fillers are well distributed in the matrix and covalently bonded to the nearby PCL, forming a striking contrast to the control in which linear PCL acts as the matrix. The DA bonds crosslinked biodegradable PCL composites exhibit decent mechanical strength (20.7 MPa) even at the MCC fraction of 65 wt%, which is superior to those (5–12.2 MPa) of the highly filled PCL composites (with filler contents of 50–63.8 wt%) reported so far. The proposed approach has sufficient expansibility for the fabrication of the highly filled polymer composites constructed by other types of matrix and fillers.
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GREEN CHEMISTRY
·
2020
·Vol. 23
·期 1
·552-560
·
IF 9.48
Peixuan Wu,Haiyang Cheng,Xinchao Wang,Ruhui Shi,Chao Zhang,Masahiko Arai,Fengyu Zhao
The fabrication of self-healing and recyclable CO2-based polymeric materials meets the requirement of sustainable development. By introducing reversible hydrogen bonds and heat-responsive Diels–Alder bonds, a new, environmentally friendly, self-healing and recyclable polyurethane-urea Diels–Alder adduct (PUUa-DA) was successfully synthesized using CO2 and furfuryl amine as renewable feedstocks. PUUa-DA was semi-crystalline and exhibited high thermal stability, 5% weight loss temperature being above 220 °C. Moreover, PUUa-DA with a cross-linked structure showed a tensile stress of 18.5 MPa, a modulus of 151 MPa and an elongation at break of 136%. The dynamic Diels–Alder bonds and hydrogen bonds provide the self-healing response and contribute to 94% recovery of the tensile strength upon heating. Therefore, PUUa-DA will have potential applications as a functional material in a wide range of practical fields. The synthesis of PUUa-DA using CO2 and bio-based furfuryl amine will be of importance in green and sustainable chemistry.
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POLYMER
·
2019
·
IF 3.771
Weilong Chen,Kun Wu,Qi Liu,Mangeng Lu
Surface modification of filler is often utilized to effectively reduce interfacial thermal resistance in thermal conductive materials . In this work, pristine graphite was modified via Diels-Alder reaction with acrylic acid to improve the inertness of graphite (AA@G). FT-IR, Raman and XPS confirmed the reaction onto the surface of graphite. A series of poly (vinyl alcohol) composite loaded with AA@G and graphite was fabricated to investigate the interfacial interaction between matrix and filler. Both XRD and DSC showed that introducing of AA@G would decrease crystallinity of PVA matrix in composite, providing convincing evidence of strong interfacial interaction. Owing to the excellent interfacial interaction, the maximum TC of composite loaded with 30 wt% AA@G reached to 21.3Wm −1 K −1 , which was 44% higher that of composite loaded with the same mass fraction of graphite (14.1Wm −1 K −1 ). With the synergistic increment in thermal conductive performance, AA@G exhibited extremely high enhanced efficiency of 358% compared with other literature. Also, good thermal stability makes AA@G potential in thermal management system and flexible electronics.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 44
·期 4
·1236-1244
·
IF 3.069
Jianfeng Xu,Xiaomin Zhao,Feixiang Liu,Lun Jin,Guohua Chen
Functionalized graphene (G-MA) was prepared by a facile wet ball milling strategy, which achieved exfoliation and functionalization of graphite simultaneously. The G-MA showed excellent dispersion in water and polar solvents. Thus, a G-MA coating was prepared from G-MA in mixed solvents (H2O–ethanol) without binder or surfactant. The scanning electron microscope (SEM) images of the G-MA coating exhibited a smooth and flat surface. The G-MA coating showed a conductivity of 769 S m−1 at room temperature, and a big increase could be found at 2000 S m−1 after thermal treatment under 200 °C for 2 h, indicating the restoration of the conjugated structure via the reverse Diels–Alder reaction. This synthetic method of functionalized graphene offers a powerful strategy for the reversible modification of the graphene electronic properties, which may expand their usage.
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Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 48
·20642-20649
·
IF 0
Jinhui Li,Guoping Zhang,Libo Deng,Songfang Zhao,Yongju Gao,Kun Jiang,Rong Sun,Chingping Wong
Covalently bonded graphene oxide/polyurethane (GO/PU) composites with significant reinforcement and thermally healable properties were developed via in situ polymerization based on Diels–Alder (DA) chemistry. The PU prepolymer was prepared with GO, 4,4-diphenylmethane diisocyanate, and poly(tetramethylene glycol) and blocked by using furfuryl alcohol firstly. Then the prepolymer was cross-linked by using bifunctional maleimide via DA chemistry. SEM shows that the GO was dispersed uniformly in the PU matrix. The DA and retro-DA reactions were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry separately. Tensile tests showed that with the incorporation of 0.1 wt% of GO, the tensile modulus of GO/PU composites increased from 9.80 MPa to 21.95 MPa, and the tensile strength and elongation at break of the GO/PU composites increased by more than 367% and 210%, respectively. Furthermore, the composites had thermally healable ability which was inspected by using an atomic force microscope and the strain–stress test. The healing efficiency of 78% on average was achieved which was determined by the recovery of breaking stress and a healing mechanism was tentatively proposed. Therefore, the covalently bonded self-healing GO/PU composites could be used as smart materials and structural materials.
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Polymers
·
2017
·Vol. 9
·期 6
·200
·
IF 3.364
Chuyao Liang,Jie Li,Min Xia,Guoping Li,Yunjun Luo
Based on the Diels–Alder reaction and hydroxyl-terminated polybutadiene (HTPB) binders of solid propellants, two novel compounds—furfuryl-terminated polybutadiene (FTPB) and trifurfuryl propane (TFP)—were designed and synthesized, and their structures were characterized. A new kind of reversible Diels–Alder reaction system was formed by FTPB as main resin,N,N′-1,3-phenylenedimaleimide (PDMI) as curing agent and TFP as chain extender. The results showed that this system had good mechanical properties with a tensile strength of 1.76 MPa and a tensile strain of 284% after curing, and the repair efficiency of the crack was 88%. Therefore, it could be used as a novel binder of energetic materials such as solid propellant and PBX explosives to provide them with self-repairing characteristics and improve the reliability for application.Keywords:Diels–Alder reaction;hydroxyl-terminated polybutadiene;binder;self-repairing;solid propellant
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