Small
·
2025
·
IF 12.1
Yifan Chen,Derui Kong,Lianfen Chen,Peter VanNatta,Hang Li,Jiaao Cheng,Chengzhi Ma,Pinghuai Liu,Yujie Song,Shanshuai Chen,Cheng-Xia Chen,Thamraa AlShahrani,Shengqian Ma
Conversion of solar energy to clean energy via naphthalenetetracarboxylic dianhydride (ND)-based organic semiconductors represents a topic of research. Nonetheless, efforts in this area are challenging due to the rapid recombination of photogenerated electron-hole (e-h) pairs arising from over-accumulation. Herein, various n -type hybrid photocatalysts, ND-TiO 2 (x:y) (x and y represent the ratios of ND and TiO 2 , respectively), featuring excellent visible-light responsiveness, fast separation and migration ability of charge carriers, and permanent porosity, are constructed via a sol–gel self-assembly approach. The rational assembly of ND with TiO 2 not only effectively inhibits the problematic overgrowth of ND but also enables the composites with excellent visible-light responsiveness, and facilitates the separation and migration of charge carriers, thus resulting in greatly improved photocatalytic H 2 evolution performance. The optimized composite ND-TiO 2 (1:10) with 0.38 wt% Pt nanoparticle loading presents a maximum hydrogen-evolution rate of 3.23 mmol·g −1 ·h −1 , with extraordinary TON (2446) and TOF (163.1 h −1 ), which are much higher than ND (0.031 mmol·g −1 ·h −1 ) and TiO 2 -Colloid (0.027 mmol·g −1 ·h −1 ) counterparts. In addition, the underlying photocatalytic mechanism is well established through comprehensive experiments and computational studies.
研究领域:
材料科学
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能源化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2018
·Vol. 10
·期 5
·552
·
IF 2.935
Xianggen Chen,Lingyun Wang,Jiuying Feng,Xianling Huang,Xiuzhi Guo,Jing Chen,Zhenyuan Xiao,Xiangjun Liang,Lijun Gao
Thermally and mechanically enhanced poly(propylene carbonate) (PPC) with networks was prepared by adding a cyclic carboxylic dianhydride, bicyclo(2,2,2)oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BTCDA), in the CO2/propylene oxide (PO) copolymerization. The obtained copolymers were characterized by FT-IR,1H NMR, DSC, and TGA. The gel, melt flow rate, hot-set elongation, and tensile properties were also measured. The formation of networks was confirmed by the presence of gel and the shape recovery after the hot-set elongation test. The minimum permanent deformation of the copolymer is 3.8% and that of PPC is 4539% higher than this value. The results show that BTCDA units are inserted into the backbone of PPC, and the PPC chains are connected successfully owing to cyclic multifunctional anhydride groups in BTCDA. With increasing feed molar ratio of BTCDA to PO from 1 to 4%, the yield strength of copolymers increases from 18.1 to 37.4 MPa compared to 12.9 MPa of PPC. The 5% weight-loss degradation temperatures and maximum weight-loss degradation temperatures greatly increase up to 276.4 and 294.7 °C, respectively, which are 58.6 °C and 55.1 °C higher than those of PPC. These enhanced properties originate from the formation of crosslinks by the rigid and bulky multifunctional dianhydride.Keywords:poly(propylene carbonate);networks;dianhydride;terpolymerization;modification
研究领域:
材料科学
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化学工程
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DOI
PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Hongyang Deng,Lixian Guo,Keping Chen,Ping Zhang,Yewei Xu,Ningning Song,Chunrong Tian,Jianhua Wang,Shuen Liang
Polyurea (PUA) elastomers have gained increasing attention in both defense and civilian fields due to its remarkable mechanical properties and protective capabilities. However, its high flammability significantly limits its application in many fields. It is challenging to achieve high flame retardant rating and maintain high mechanical properties simultaneously. Synergistic combination of different types of flame retardants is essential for this purpose. Herein we report a highly efficient synergistic combination of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and ammonium phosphate (APP) for flame retardance of PUA. BTDA contributes to excellent char-forming in solid phase, and APP contributes to radical scavenging in gaseous phase. By incorporating BTDA and APP as additive flame retardants in PUA, the melt dripping in combustion was entirely suppressed, and V-0 rating in UL-94 test was achieved. The heat release rate and the release of smoke and toxic gases were greatly reduced. Meanwhile, the mechanical properties of PUA were maintained very well. The PUA composites with outstanding flame retardancy and mechanical properties may serve as ideal protective materials in a variety of applications.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
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2015
·Vol. 3
·期 35
·18180-18189
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IF 7.443
Yan Li,Yanan Wen,Lihuan Wang,Jianxin He,Salem S. Al-Deyab,Mohamed El-Newehy,Jianyong Yu,Bin Ding
By virtue of the affinity of pyromellitic dianhydride (PMDA) for lead(II) ion (Pb2+) and the inherent structural merits of electrospun nanofibrous membranes, a novel solid-phase nanofibrous material was facilely fabricated via the modification of deacetylated cellulose acetate membranes with PMDA (DCA-PMDA). The resultant DCA-PMDA can be applied for the simultaneous naked-eye detection and removal of Pb2+ from water matrixes by simple filtration followed by treatment with Na2S solution. Importantly, the color of the DCA-PMDA changes from white to dark yellow-brown due to the formation of PbS, which can be leveraged for the colorimetric detection of Pb2+ by the naked eye with a detection limit of 0.048 μM. Under the same circumstances, the maximum adsorption capacity was determined to be as high as 326.80 mg g−1. Furthermore, the extraction of Pb2+ from DCA-PMDA was possible with HNO3. The regenerated membrane that remained maintained the high sensitivity to Pb2+ and exhibited almost the same adsorption capacity as the original membrane. Therefore, the proposed membrane offers a cost-effective material that can be considered as a viable alternative for effectively detecting and removing toxic Pb2+ from water samples.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Jie Li,Shufeng Liu,Ge Zhu,Chunshan Lu,Yuxia Ba,Guofei Chen,Xingzhong Fang
Two isomeric dianhydride monomers, 1,4-bis(3,4-dicarboxyphenoxy)-2- tert -butylbenzene dianhydride (4,4′-TBHQDA) and 1,4-bis(2,3-dicarboxyphenoxy)-2- tert -butylbenzene dianhydride (3,3′-TBHQDA), were successfully synthesized from tert -butylhydroquinone and nitrophthalonitrile. Two series of polyetherimides (PEIs) were synthesized by chemical imidization using the above dianhydrides with four common commercially available diamines. The effects of dianhydrides with isomerization and tert -butyl group on the thermal properties, optical properties, melt processability, solubility, and mechanical properties of PEIs were systematically studied. Among them, PEI-2(a-d) derived from 3,3′-TBHQDA displayed better comprehensive performance than other PEIs, which showed well T g s at 234–261 ℃, good optical properties of 82–86 % at 450 nm, extremely low melt viscosities of 30–59 Pa·s at 400 ℃, excellent solubility and good mechanical properties (tensile modulus of 2.7–3.5 GPa, tensile strengths of 90–97 MPa and elongations at break of 3.4–4.8 %).
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 135
·期 17
·46159
·
IF 1.901
Sheng Xu,Liang Shen,Cailian Li,Yan Wang
In this work, three dianhydrides with similar chemical structures, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), 4,4′-oxydiphthalic anhydride (ODPA), and pyromellitic dianhydride (PMDA), are employed for the crosslinking modification of poly(vinyl alcohol) (PVA) membranes for ethanol dehydration via pervaporation. The changes in crosslinking degree, surface hydrophilicity, and glass-transition temperature are investigated and compared. Compared to the pure PVA membrane, all crosslinked membranes show higher fluxes but lower separation factors, because of the higher fractional free volume and the lower hydrophilicity by the crosslinking of the PVA matrix, respectively. In addition, all crosslinked PVA membranes exhibit similar flux, and the separation factor presents a decreasing order of PVA/PMDA-2 > PVA/ODPA-2 > PVA/BTDA-2, which is in the reverse order of their hydrophilicity, probably because of the reduction in the swelling resistance. With the PMDA content increasing from 0.01 to 0.04 mol/(kg PVA) in the PVA/PMDA crosslinked membranes, the crosslinking degree is enhanced and the hydrogen bonding is weakened, resulting in a flux increase from 120.2 to 190.8 g m −2 h −1 , but the separation factor declines from 306 to 58. This work is believed to provide useful insight on the chemical modification of PVA membranes for pervaporation and other membrane-based separation applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46159.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2014
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IF 2.269
Linhua Zhu,Xianghui Wang,Luyong Wu,Yi Luo,Yuqing Zhu,Qiang Lin,Zaifeng Shi
Poly(propylene carbonate pyromellitic dianhydride) (PPCPD) was synthesized from carbon dioxide (CO 2 ), propylene oxide (PO) and pyromellitic dianhydride (PD) using Zn–Fe(III) double metal cyanide (DMC) as a catalyst. The thermal properties of PPCPD were investigated with thermogravimetric analysis (TGA) and differential thermal gravity (DTG). TGA and DTG curves of PPCPD indicate that the decomposition process of PPCPD includes 2 stages: the chain scission decomposition stage (1st decomposition stage) and the chain unzipping decomposition stage (2nd decomposition stage). According to the Flynn–Wall–Ozawa method, the average apparent activation energies ( E a ) of 1st and 2nd decomposition stages are 98.95 kJ/mol and 150.39 kJ/mol, respectively. The result shows that the chain unzipping decomposition is difficult compared with the chain scission decomposition in the process of PPCPD decomposition. Furthermore, according to the Phadnis–Deshpande model, the degradation kinetic models of 1st and 2nd decomposition stages of PPCPD follow a phase boundary mechanism and a 3-dimensional diffusion mechanism, respectively.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 130
·107793-107803
·
IF 3.84
Shanyou Liu,Yunhe Zhang,Xueping Wang,Haiwei Tan,Ningnig Song,Shaowei Guan
To investigate the properties of hyperbranched polyimides (HBPIs) for potential optical applications, novel fluorinated tetra-amine monomers with ether and sulfonyl groups, 4,4′-di[3,5-di(2-trifluoromethyl-4-aminophenoxy)phenoxy]sulfone, and five kinds of long-chain dianhydrides, have been designed and synthesized. A series of anhydride-terminated hyperbranched polyimides have been prepared via a two-step method with chemical imidization. The HBPIs possess outstanding solubility and show excellent thermal and optical properties. The glass transition temperatures (Tg) of the HBPIs range from 230–242 °C determined by differential scanning calorimetry (DSC), and 232–263 °C by thermomechanical analysis (TMA), depending on the dianhydride used. The 5% weight loss temperatures are in the range of 480–533 °C, showing high intrinsic thermal-resistant characteristics of the HBPIs. The HBPI films show good optical transparency, higher than 80% at 800 nm. The cast polyimide films have favorable mechanical properties with tensile strengths of 91–112 MPa, elongation at break of 5.99–7.99%, and initial modulus of 2.14–2.57 GPa. The polyimides exhibit average refractive indices of 1.5780–1.6271, and birefringence of 0.0065–0.0079 because of the hyperbranched structure. The PI derived from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane possesses the lowest refractive indices due to the high fluorine content in the polymer chain.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Hongyang Deng,Lixian Guo,Keping Chen,Pingfeng You,Ping Zhang,Yewei Xu,Ningning Song,Chunrong Tian,Jianhua Wang,Shuen Liang
Polyurea (PU) elastomers have become increasingly popular in recent years due to their exceptional blast mitigation, ballistic protection, and wear resistance properties. However, their applications as protective materials are often limited as a result of their high flammability. In this study, aromatic dianhydrides (ArDAs) were employed to capture the thermal decomposing products of PU during combustion and facilitate the generation of highly heat-resistant aromatic polyimides (i.e., end group capturing effect), thus enhancing the material's char-forming ability and improving its flame retardancy. The ArDAs were found to significantly reduce the peak heat release rate (PHRR), total heat release (THR), total smoke release (TSR), and total CO release (TCO) of PU, and meanwhile increased the amount of char residue. At 20 wt% content of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), PHRR, THR, TSR and TCO of PU were reduced by 70.6%, 32.5%, 44.7% and 58.8%, respectively, the char residue was increased by 405%, and the mechanical properties of PU were well maintained (88.5% tensile strength and 91.0% elongation at break of pure PU). These findings demonstrate that ArDAs could serve as a new kind of halogen/phosphorus-free flame retardant for PU elastomers.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2022
·Vol. 14
·期 19
·4132
·
IF 4.967
Yao Wang,Xiangfu Liu,Jiulin Shen,Jianqiao Zhao,Guoli Tu
A new series of colorless polyimides (CPIs) with outstanding thermal properties and mechanical properties were fabricated by the copolymerization of a novel dianhydride and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 2,2′-bistrifluoromethyl benzidine (TFDB). The novel dianhydride, 10-oxo-9-phenyl-9-(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetraacid dianhydride (3FPODA), possessed a rigid semi-alicyclic structure, –CF3and phenyl side groups, and an active carbonyl group. Benefitting from the special structure of 3FPODA, the glass transition temperatures (Tg) of the new CPIs improved from 330 °C to 377 °C, the coefficient of thermal expansion (CTE) decreased from 46 ppm/K to 24 ppm/K, and the tensile strength (TS), tensile modulus (TM), and elongation at break (EB) increased from 84 MPa to 136 MPa, 3.2 GPa to 4.4 GPa, and 2.94% to 4.13% with the increasing amount of 3FPODA, respectively. Moreover, the active carbonyl group of the 3FPODA could enhance the CPI’s adhesive properties. These results render the new dianhydride 3FPODA an ideal candidate monomer for the fabrication of high-performance CPIs.Keywords:colorless polyimide;new dianhydride;coefficient of thermal expansion;glass transition temperatures
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Petroleum Science
·
2018
·Vol. 15
·期 1
·146-156
·
IF 1.624
Zhang Rui,Xu Xiaoying,Cao Bing,Li Pei
The pyromellitic dianhydride (PMDA) crosslinked poly(vinyl alcohol) (PVA) was coated on top of the PAN ultrafiltration membrane to form a PVA/PAN composite PV membranes for wastewater desalination. The composite membranes have high application value in industrial wastewater treatment. By varying the membrane fabrication parameters including the weight percent (wt%) of the PMDA, the crosslink temperature and duration, membrane with the best desalination performance was obtained. The composite membrane with a 2-μm-thick PVA selective layer containing 20 wt% of PMDA and being crosslinked at 100 °C for 2 h showed the highest NaCl rejection of 99.98% with a water flux of 32.26 L/(m 2 h) at 70 °C using the 35,000 ppm NaCl aqueous solution as feed. FTIR spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis and scanning electron microscope have been used to characterize the structures and properties of both the crosslinked PVA dense films and PVA/PAN composite membranes. The effects of the concentrations of PMDA, the crosslinking time and temperature to the membrane water contact angle, swelling degree, salt rejection and water flux were systematically studied.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Da Ke,Minjia Wang,Jiancheng Ruan,Xinzhi Chen,Shaodong Zhou
Continuous preparation of pyromellitic dianhydride (PMDA) from durene has been studied using a fixed-bed reactor. The reaction was performed using a phosphorus-vanadium-titanium ternary catalyst. Relatively high selectivity and yield of PMDA was obtained. The in-situ characterization was combined with theoretical calculation to reveal the reaction mechanisms, and the remarkable doping effect was discussed.
研究领域:
化学工程
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催化化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）