Frontiers of Chemical Science and Engineering
·
2024
·Vol. 18
·期 12
·1-10
·
IF 4.3
Zhang Yue-Rong,Qin Zhen,Gu Song,Zhao Jia-Xin,Xiang Xian-Yue,Liu Chuan,Wang Yu-Zhong,Chen Li
To date, sustainable thermosetting polymers and their composites have emerged to address recyclability issues. However, achieving mild degradation of these polymers compromises their comprehensive properties such as flame retardancy and glass transition temperature ( T g ). Moreover, the reuse of degradation products after recycling for upcycling remains a significant challenge. This study introduces phosphorus-containing anhydride into tetraglycidyl methylene diphenylamine via a facile anhydride-epoxy curing equilibrium with triethanolamine as a transesterification modifier to successfully prepare flame-retardant, malleable, reprocessable, and easily hydrothermally degradable epoxy vitrimers and recyclable carbon fiber-reinforced epoxy composites (CFRECs). The composite exhibited excellent flame retardancy and a high T g of 192 °C, while the presence of stoichiometric primary hydroxyl groups along the ester-bonding crosslinks enabled environmentally friendly degradation (in H 2 O) at 200 °C without any external catalyst. Under mild degradation conditions, the fibers of the composite material were successfully recycled without being damaged, and the degradation products were reused to create a recyclable adhesive with a peel strength of 3.5 MPa. This work presents a method to produce flame retardants and sustainable CFRECs for maximizing the value of degradation products, offering a new upcycling method for high-end applications.
研究领域:
材料科学
·
可持续发展
✓ 已验证
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 23
·3347
·
IF 4.7
Chiara Botta,Corinna Maria Grottola,Davide Amato,Maria Rosaria Acocella
As an alternative to fossil-based polymers, polylactide acid (PLA) has stimulated a significant research effort in the past few years due to the demand for environmentally friendly products. Even though PLA is considered a sustainable or bio-based material, the long-term degradation in ambient conditions increases the volume of waste at end-of-life. To overcome this issue, PLA waste can be recycled to produce new manufactures; however, this approach does not always ensure the same mechanical properties as the original PLA. This study shows for the first time that adding biochar, a carbon material derived from biomass pyrolysis, enhances the processability and stability of composite recycled PLA. Composites are provided in 1, 2.5, and 5 wt% of the biochar filler, resulting in good processability, a higher modulus of up to 20%, and a higher stability to degradation in the presence of UV aging treatment with respect to the raw material. Additionally, DSC analysis shows a significant nucleation effect induced by the biochar that achieves 30% crystallinity from an essentially amorphous PLA.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2024
·Vol. 31
·期 3
·1-13
·
IF 2.6
Chi Yongbo,Li Mingzhuan,Chen Tongzhou,Liu Xingyao,Xie Ximing,Xu Jian
Epoxy resin is difficult to recycle and degrade due to its permanently crosslinked network structure after complete curing. Therefore, the traditional treatment of epoxy resin waste is landfill or incineration, which not only causes environmental pollution and the waste of resources but also limits its secondary applications. To solve this problem, a repairable and recyclable epoxy vitrimer, composed of bisphenol A glycidyl ether, glutaric anhydride, and carboxy-terminated polyether, was prepared in this work. The polyether-modified epoxy vitrimer showed good mechanical properties with a flexural strength of 69.2 MPa and a fracture toughness of 9.17 MJ/m 3 . Dynamic ester exchange reactions at elevated temperatures enable the epoxy vitrimer to achieve network rearrangement. As a result, the epoxy vitrimer exhibits excellent self-healing (complete healing of cracks within 5 min), shape memory, and recycling properties (75% retention of flexural strength). Furthermore, the prepared carbon fiber-reinforced vitrimer composites can be degraded by ethylene glycol for effective recycling of carbon fibers. Herein, the fracture toughness and reparability of the epoxy vitrimer were effectively improved by introducing the carboxy-terminated polyether into the crosslinked network, which has practical value for extending service life and reducing energy consumption in its engineering applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 25
·14024-14032
·
IF 3.049
Yakun Guo,Dongli Zou,Wanqiu Zhu,Xiaojiao Yang,Pengxiang Zhao,Changan Chen,Maobing Shuai
A repeatable self-healing epoxy composite mechanically enhanced by graphene nanosheets (GNS) was prepared from an epoxy monomer with Diels–Alder (DA) bonds, octanediol glycidyl ether (OGE) and polyether amine (D230). The GNS/epoxy composites, with a maximum tensile modulus of 14.52 ± 0.45 MPa and elongation at break more than 100%, could be healed several times under Infrared (IR) light with the healing efficiency as high as 90% through the molecule chain mobility and the rebonding of reversible DA bonds between furan and maleimide. Also, they displayed excellent recyclable ability by transforming into a soluble polymer, which offers a wide range of possibilities to produce epoxy flexible materials with healing and removable abilities.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
SYNTHETIC COMMUNICATIONS
·
2012
·
IF 1.062
Xi'an Chen,Huayue Wu,Shun Wang,Shaoming Huang
Nano-TiO2 is an effective heterogeneous catalyst for the ring opening of epoxides with aromatic amines to afford β-amino alcohols in good to excellent yields at room temperature under solvent-free conditions. It was found that the catalyst is recyclable, and the activity of the catalyst was not weakened markedly even after several reaction cycles. In addition, the catalytic activity of TiO2 strongly depends on particle size or surface area.
研究领域:
化学
·
催化材料科学
✓ 已验证
DOI
高影响因子
FIBERS AND POLYMERS
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2024
·Vol. 25
·期 3
·797-805
·
IF 2.2
Zhang Xi,Shi Zhengjun,Xu Pengfei,Zhang Qi,Huang Xudong,Xing Guiying,Shao Linjun,Qi Chenze
Supported cobalt catalysts have attracted more and more attention for their easy separation and recyclability. Herein, cobalt-embedded pyridine functionalized polystyrene superfine fibers were readily fabricated by electrospinning. Then, the pyridine functionalized polystyrene and polystyrene molecules inside the fibers were cross-linked by paraldehyde to improve the fiber stability. The synthesis of pyridine functionalized polystyrene and cross-linking of polystyrene molecules inside the fibers were confirmed by FT-IR spectra. The fiber morphologies were characterized by SEM. The dispersion of cobalt species was analyzed by SEM–EDS, XRD and TEM. Finally, the Heck reactions were employed to evaluate the catalytic performance of this novel fibrous catalyst. The catalysis results show that this novel fiber catalyst exhibited excellent catalytic activity for the Heck reactions of aromatic iodides with alkenes to afford coupling products with yields over 80%. Moreover, due to the embedment of cobalt species and chelation of pyridine groups, this novel fiber catalyst can be reused five times with little loss of catalytic activity. In all, we have developed a highly active and stable supported cobalt catalyst, which holds great potential for green chemical processes.
研究领域:
化学工程
·
催化材料
·
绿色化学
✓ 已验证
DOI
高影响因子
Polymers
·
2018
·Vol. 10
·期 4
·385
·
IF 2.935
Lei Zhu,Bojie Li,Shan Wang,Wei Wang,Liansheng Wang,Liang Ding,Caiqin Qin
The first example of an environmentally-benign chitosan supported copper catalyzed conjugate silylation of α,β-unsaturated acceptors was accomplished in water under mild conditions. This protocol provides an efficient pathway to achieve an important class of β-silyl carbonyl compounds and the desired products were obtained in good to excellent yields. Gram-scale synthesis and easy transformation of obtained β-silyl products were also been demonstrated. Remarkably, this chitosan supported copper catalyst can be easily recycled and reused six times without any significant decrease of catalytic activity. The advantages of this newly developed method include operational simplicity, good functional group tolerance, scale-up ability, ready availability, and easy recyclability of catalyst.
研究领域:
有机化学
·
绿色化学
·
催化反应
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Qiao Wang,Wei Wang,Boyin Yan,Wenxin Shi,Fuyi Cui,Ce Wang
The present development gives an insight into the effect of the distribution of bimetallic sites in denitrification. A highly-dispersed Pd-Cu bimetallic catalyst supported by titanium dioxide nanofibers (Pd-Cu/TiO 2 ) was in situ fabricated by electrospinning and subsequent calcination and chemical reduction, and then applied in the catalytic reduction of water phase nitrate (NO 3 − ) to nitrogen gas (N 2 ). Compared with ex situ Pd-Cu impregnated catalyst, the in situ Pd-Cu/TiO 2 nanofibers exhibited the high nitrate removal efficiency, selectivity and fast kinetics (about twice that of impregnated ones). These good catalytic performances are mainly benefited from increased active sites and raised ratio of nitrogen to hydrogen on them, which are brought about by the well-dispersed and closely connected Pd-Cu bimetallic nanoparticles in TiO 2 nanofiber matrix. Moreover, the in situ nanofiber matrix provides a physical barrier to inhibit bimetallic nanoparticles movement, aggregation and leakage from the support into water, and hence significantly enhances the recyclability for nitrate reduction.
研究领域:
环境科学
·
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Yachen Wang,Mingxing Gao,Sai Li,Jun Liu,Anchao Feng,Liqun Zhang
Traditional thermoset polymeric materials pose an enormous burden on the environment due to permanent covalent cross-links that make them difficult to reprocess or recycle. Herein, we describe the facile synthesis of recyclable, healable and reprocessable poly-dimethylsiloxane (PDMS)/cellulose nanocrystals (CNC) composites via engineering dynamic covalent bond (DCB) vinylogous urethane between the polymer-polymer and polymer-CNC. We successfully prepared the amine-modified CNC, evidenced by the analysis of FTIR, XPS and Element analysis , and its surface morphology as well as its size compared to the pristine one is not altered via XRD and TEM analysis . The DCBs are constructed not only between polymer chains, but also on the interface between polymer and CNC. Interestingly, the macromolecular cross-linker synthesized by RAFT polymerization significantly improves the mechanical properties of PDMS-based CNC vitrimer, without affecting its recycling and reprocessing properties. Remarkably, DCB vinylogous urethane endows this vitrimer good self-healing, reprocessing and recycling and this DCB can be effectively reshaped by the catalyst-free transamination of the vinylogous urethane through hot pressing or welding. It is emphasized that this macromolecular cross-linker containing β -keto acids obtained by RAFT polymerization can significantly broaden the application range for DCB vinylogous urethane. In general, this work could provide a facile approach to design and fabricate high performance renewable CNC based composites with excellent self-healing, reprocessing and recycling capabilities.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2013
·Vol. 3
·期 38
·17485-17491
·
IF 2.562
Yu Qin,Ping Chen,Jinzhao Duan,Junxing Han,Hui Lou,Xiaoming Zheng,Haiping Hong
Carbon nanofiber-supported molybdenum carbide catalysts (Mo2C/CNF) with different loadings were prepared by the carbothermal hydrogen reduction method. Characterizations with Raman, XRD, N2-TGA, SEM, TEM and HAADF-STEM confirmed that Mo2C nanoparticles were successfully supported on the carbon nanofibers. The optimal reaction conditions with model compounds on Mo2C/CNF had a conversion of 98.03% and yield of 95.26%. It is interesting to note that a low evaporation rate positions the Mo2C nanoparticles on the outside of the CNF due to the capillary effect and the Mo2C nanoparticles on the outside of the CNFs showed high catalytic activity compared to ones on the inside of the CNFs. The Mo2C/CNF catalyst was recycled 5 times without any apparent loss of catalytic activity. Catalytic performances of Mo2C/CNF, Mo2C/AC (activated carbon) and Mo2C/CNT (multi-walled carbon nanotubes) were examined using methyl palmitate and maize oil. The results showed that molybdenum carbide could be a potential substitute for noble metals in transformation of vegetable oils.
研究领域:
材料科学
·
催化化学
·
能源化学
·
纳米技术
·
绿色化学
✓ 已验证
DOI
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2022
·Vol. 86
·期 10
·2718-2731
·
IF 2.43
Wang Bo,Cao Xuan,Li Shifeng,Yao Shuhua,Wang Haibo
Nickle-copper ferrite (Ni 0.5 Cu 0.5 Fe 2 O 4 ) supported on activated carbon (AC) (AC@Ni 0.5 Cu 0.5 Fe 2 O 4 ) was synthesized and used as adsorbent, photocatalyst, and activator of peroxydisulfate (PDS) to realize the removal of ciprofloxacin (CIP). AC@Ni 0.5 Cu 0.5 Fe 2 O 4 properties were characterized by scanning electron microscope equipped with energy-dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), N 2 adsorption-desorption isotherm plot of Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH), vibrating sample magnetometer (VSM). A rapid removal rate (94.30%) of CIP was achieved on AC@Ni 0.5 Cu 0.5 Fe 2 O 4 /PDS/UV system with the condition of catalyst dosage 0.30 g/L, initial pH 7.3, PDS addition 0.20 mM, CIP concentration 10 mg/L (200 mL), UV 28 W, in 30 min. Free radical quenching experiments indicate that reactive species of superoxide (·O 2 − ), holes (h + ), sulfate radicals (SO 4 − ·) and hydroxyl radicals (·OH) were produced and all worked. The reusability test demonstrated that AC@Ni 0.5 Cu 0.5 Fe 2 O 4 could be recycled five times with minimal performance reduction for the removal of CIP. The XRD and SEM of the after used AC@Ni 0.5 Cu 0.5 Fe 2 O 4 did not change significantly, which further showed its stability and recyclability. This work might provide new insight into the application of AC@Ni 0.5 Cu 0.5 Fe 2 O 4 in photocatalysis coupled with adsorption in peroxydisulfate assisted system and has high potential in CIP removal. AC@Ni 0.5 Cu 0.5 Fe 2 O 4 was synthesized by a simple co-precipitation method. AC@Ni 0.5 Cu 0.5 Fe 2 O 4 has a large specific surface area and thus can provide more reaction sites. AC@Ni 0.5 Cu 0.5 Fe 2 O 4 can be used as adsorbent, photocatalyst, and activator of peroxydisulfate. AC@Ni 0.5 Cu 0.5 Fe 2 O 4 displayed an excellent recyclability.
研究领域:
环境科学
·
材料科学
·
化学工程
·
水处理技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 94
·91791-91797
·
IF 3.289
Jia-yi Pu,Jin-quan Wan,Yan Wang,Yong-wen Ma
In this study, Co-based MOF with a 2D structure, 3D microrod structure and 3D nano-dodecahedral structure was synthesized by the coordination of cobalt ions and different organic ligands. Then, Co3O4, which was derived from these Co-based MOFs, was used to activate oxone for RhB degradation. It was found that the morphology and structure of the templates can significantly influence the formation of the nano Co3O4 products, which has an indirect effect on the catalytic ability of the resulting Co3O4 for oxone to degrade RhB. Among the products, nano-sphere Co3O4, which was derived from a template with a 3D nano-dodecahedral structure (ZIF-67) can effectively activate oxone to degrade RhB. Under neutral conditions, the rate constant of the degradation of RhB (0.1 mM) was 0.0509 min−1 with 50 mg L−1 catalyst and 1.0 mM oxone based on first-order kinetics. In addition, the influence of a series of parameter factors (pH, the dosage of catalyst and oxone) on the catalyst was also studied. Low cobalt ion dissolution (0.04 mg L−1 at pH = 3, <0.01 mg L−1 at pH = 7) and good recyclability (degradation rate of RhB after 5 cycles: close to 96%, 89% at pH = 7, pH = 3) further proved that the as-prepared Co3O4 can be used as a promising catalyst.
研究领域:
环境化学
·
材料科学
·
催化化学
·
纳米技术
·
环境污染治理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）