POLYMER BULLETIN
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2024
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IF 3.1
Yan Xin,Yang Jianming,Zhang Hexin,Yoon Keun-Byoung,Chen Min
The single-sited metallocene catalyst has attracted significant attention due to its high activity and application in olefin polymerization industry. In this work, we introduced a strategy of in situ modification of metallocene catalyst with pyrene through π–π stacking to study the effect in olefin polymerization. After activated by MMAO, the pyrene-modified metallocene catalyst exhibited high activities (up to 1333 kg mol −1 h −1 ) in ethylene polymerization, which was 1.9 times higher than that of the pyrene free catalyst system. This could be because the electron-donating ability of cyclopentene to the transition metal was enhanced through π–π interaction of pyrene with cyclopentene. The copolymerization of ethylene and 1-hexene was also studied. The pyrene-modified metallocene catalyst system performs with higher activity in the copolymerization with a lower monomer incorporation ratio. Density functional theory (DFT) calculations indicated the formation of π–π interaction between the Zr center with pyrene molecule leading to the increase in steric hindrance and electron density. Graphical abstract
研究领域:
高分子化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 3
·270
·
IF 4.501
Wenqian Kang,Sheng Chen,Xiong Wang,Guangquan Li,Xiaoyu Han,Minfeng Da
Porous organic polymers (POPs) are widely used in various areas such as adsorption, separation and catalysis. In the present work, ionic liquid-modified porous organic polymers (IL-POPs) synthesized by dispersion polymerization were applied to immobilize metallocene catalysts for olefin polymerization. The prepared IL-POPs were characterized by Fourier transform infrared spectrometer (FT-IR), nitrogen sorption porosimetry, X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), inductively coupled plasma atomic emission spectrometer (ICP) and scanning electron microscope (SEM) analysis. The IL-POPs obtained pores with surface specific area (SSA) ranging from 16.9 m2/g to 561.8 m2/g, and total pore volume (TPV) ranging from 0.08 cm3/g to 0.71 cm3/g. The supported catalysts Zr/MAO@IL-POPs exhibit great activity (3700 kg PE/mol·Zr·bar·h) in ethylene polymerization, and the GPC-IR results show that the polyethylene has narrow molecular weight distribution (2.2 to 2.8). The DSC results show that the melting point of prepared polyethylene was as high as 138 °C, and the TREF analysis results indicate that they have similar chemical composition distribution with elution temperature at 100.5–100.7 °C.Keywords:ionic liquid;porous organic polymer (POP);metallocene catalyst;ethylene polymerization;heterogeneous polymerization
研究领域:
材料科学
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化学工程
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高分子科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2025
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IF 2.7
Qingyun Chu,Yun Sun,Yuanlong Yu,Xuelian He
To address the inherent limitations in impact resistance of isotactic polypropylene, strategic incorporation of ethylene monomers into polypropylene chains is implemented as an effective toughening modification strategy. In this study, the Me 2 Si(2-Me-4-PhInd) 2 ZrCl 2 /(Ph 3 C)B(C 6 F 5 ) 4 catalytic system is employed for ethylene-propylene copolymerization, with particular emphasis on elucidating the influence of alkyl-aluminum species on propylene homo-polymerization kinetics. Systematic evaluation of four distinct alkyl-aluminum compounds as cocatalyst reveals that tri-isobutyl-aluminum demonstrates optimal performance, achieving both the maximum polymerization activity (44.16 × 10 6 g mol −1 h −1 ). Ethylene-propylene block copolymers are synthesized via a sequential two-stage polymerization approach, copolymers exhibiting both distinctive thermal characteristics and superior macroscopic performance. Prolonged ethylene–propylene copolymerization duration induces notable structural evolutions in the block copolymers, proportion of flexible random copolymer segments increases, and weight-average molecular weight reduces from 21.15 × 10 6 to 10.83 × 10 6 g mol −1 accompanied by narrowed polydispersity (Đ from 5.18 to 4.02). Comparative studies with MAO-activated systems further reveal that the current catalytic system produced block copolymers with enhanced molecular weights ( M w = 34.11 × 10 4 g mol −1 ), tighter molecular weight distributions (Đ = 2.46), and elevated propylene content.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2016
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IF 3.782
Zain-ul-Abdin,Li Wang,Haojie Yu,Muhammad Saleem,Muhammad Akram,Hamad Khalid,Nasir M. Abbasi,Xianpeng Yang
Ferrocene-based derivatives are widely used as ferrocene-based burning rate catalysts (BRCs) for ammonium perchlorate (AP)-based propellant. However, in long storage, small ferrocene-based derivatives migrate to the surface of the propellant, which results in changes in the designed burning parameters and finally causes unstable combustion. To retard the migration of ferrocene-based BRCs in the propellant and to increase the combustion of the solid propellant , zero to third generation ethylene diamine-based ferrocene terminated dendrimers ( 0G , 1G , 2G and 3G ) were synthesized. The synthesis of these dendrimers was confirmed by 1 H NMR and FT-IR spectroscopy. The electrochemical behavior of 0G , 1G , 2G and 3G was investigated by cyclic voltammetry (CV) and the burning rate catalytic activity of 0G , 1G , 2G and 3G on thermal disintegration of AP was examined by thermogravimetry (TG) and differential thermogravimetry (DTG) techniques. Anti-migration studies show that 1G , 2G and 3G exhibit improved anti-migration behavior in the AP-based propellant.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
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2013
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IF 3.777
Chang Su,Lingmin Wang,Lihuan Xu,Cheng Zhang
A novel ferrocene-contained pyrrole, 4-(1H-pyrrol-1-yl) phenyl ferrocenecarboxylate (FcPy) was synthesized by esterification of 4-(1H-pyrrol-1-yl) phenol (PLPY) and ferrocenecarboxylic acid. Then the homopolymer of FcPy (PFcPy), copolymer of FcPy and pyrrole (P(FcPy-co-Py)), polypyrrole (PPy) were prepared by chemical oxidative polymerization. And the structure, morphology, electrochemical properties of prepared polymers were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), cyclic voltammograms (CV) and electrochemical impedance spectra (EIS), respectively. Also, the charge/discharge properties of the prepared polymers were studied by galvanostatic charge–discharge testing. The results demonstrated that the introduction of ferrocene to polypyrrole obviously improved the specific capacity of PPy cathode and gave a well-defined plateau at the potential rang of about 3.5 V. Under our experimental conditions, the discharge capacity of undoped PPy-based electrodes only presented 16.5 mAh g −1 at 20 mA g −1 between 2.5 and 4.2 V, while PFcPy-based electrodes exhibited an initial discharge capacity of up to 43.2 mAh g −1 . Specially, the P(FcPy-co-Py)-based electrodes even showed a discharge capacity of 68.1 mAh g −1 and the improved discharge platform, which were ascribed to the resonance doping effect of pendant group, the advanced electrochemical nature of ferrocene moiety and the loose morphology of copolymer.
研究领域:
材料科学
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电化学
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DOI
高影响因子
JOURNAL OF ORGANOMETALLIC CHEMISTRY
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2022
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IF 2.345
Li Dai,Di Xu,Peng-Fei Song,Jun Zhang
Featured by abundant derivation and powerful catalytic activities, chiral catalysts and ligands with oxazolinyl ferrocenes core play a vital role in the area of enantioselective transformations. Despite great researches on phosphine ligands with oxazolinyl ferrocene silyl ether core have been broadly explored, the example of N,O -ferrocene compounds with identical core is rare. We herein disclosed the practical approaches to the preparation of planar chiral oxazolinyl hydroxyl ferrocene silyl ethers. Several available methods were employed for the establishment of the configuration on planar chirality , which considered as key parameter for the subsequent relative products. Furthermore, an array of N,O,O- tridentate ferrocenes was obtained through desilylation treated with TBAF. The absolute stereochemical configuration of the synthesized ferrocene derivatives was determined by X-ray diffraction.
研究领域:
有机化学
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催化化学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2017
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IF 3.387
Xiong Wang,Zhenyou Li,Xiaoyu Han,Zhengang Han,Yongxiao Bai
Porous organic Polymers (POPs) can not only exhibit high specific surface area and pore volume, but also tunable pore size distribution. Herein, copolymers of 2-hydroxyethylmethylacrylate (HEMA) and divinylbenzene (DVB) with specific pore structure were synthesized via a dispersion polymerization strategy, and then immobilized metallocene catalysts with well-defined pore structure were obtained on the produced POP supports. The nitrogen sorption and Gel permeation chromatography (GPC) results demonstrate that the pore structure of the immobilized metallocene catalyst is highly dependent on the pore structure of the POPs , and the pore structure of metallocene catalysts or the POPs has a significant influence on the molecular chain growth of the produced polyethylene. By tuning the distribution of the active species scattered in the micro- and the narrow meso-pore range (roughly ≤4 nm), the chain growth of the polyolefin can be tailored effectively during the polymerization process, although differential scanning calorimetry (DSC) and temperature rising elution fractionation (TREF) results show that the chemical composition distributions (CCDs) of produced PE from the POPs-supported metallocene catalysts are not determined by polymerization activity or molecule chain length, but mainly by the active site species scattered in the supported catalysts. Scanning electron micrograph (SEM) shows that the produced polyethylene has highly porous fabric which consists of nanofiber and spherical beads of micron dimension.
研究领域:
高分子化学
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催化化学
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材料科学
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纳米材料
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聚合物科学
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石油化工
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
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IF 9.965
Jiahui Yang,Liu Yang,Qin Li,Liangke Zhang
Ferrocene and its derivatives have great potential for biomedical applications, but few related studies have been reported. In this study, copper ions and ferrocene derivatives were used for the first time to construct the ferrocene-based nanoparticles (Cu-Fc) with a hydrated particle size of approximately 220 nm. Their good photothermal conversion properties were verified in vitro and in vivo for the first time, indicating that they could be used as a novel photothermal agent for tumor treatment. In addition, the nanoparticles exhibited efficient Fenton effect under weakly acidic conditions, indicating that they can generate hydroxyl radicals ( OH) to kill tumors in the weakly acidic environment of the tumor-specific microenvironment. More importantly, the nanoparticles can deplete glutathione (GSH), thus further enhancing Fenton effect-mediated chemodynamic therapy (CDT). Multifunctional ferrocene-based nanoparticles ( [email protected] ) were obtained after loading the chemotherapeutic drug doxorubicin hydrochloride (DOX). The results of in vitro and in vivo experiments showed that [email protected] could enhance tumor treatment by the combination of chemo/CDT/photothermal therapy (PTT).
研究领域:
生物医学工程
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纳米技术
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癌症治疗
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产品关联
DOI
PubMed
高影响因子
Journal of Coatings Technology and Research
·
2018
·Vol. 15
·期 3
·593-602
·
IF 1.619
Li Lin,Wang Yunli,Zhu Yingchun
Metallocene polyethylene/nano-silver coatings were prepared by a facile air-spray method on polymer films. Different from the prevailing strategy to endow polyethylene with antibacterial performance, we used metallocene polyethylene sol and nano-silver as a precursor to deposit coatings on polymers at a relatively low operating temperature. Antibacterial coatings with excellent mechanical properties, water resistance, and low silver release were achieved. The composite coatings were examined in terms of surface characteristics, mechanical properties, and antibacterial activity against two representative bacterial strains including Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). The composite coatings exhibited favorable microstructure, good mechanical properties, and suitable crystallinity. The antimicrobial tests indicated that the fabricated composite coatings showed promising antibacterial activity against E. coli and S. aureus . Furthermore, Ag ions released by the composite coating after 30 days were under 1.2 ppb. These results indicated a promising prospect of the composite coating for wide antibacterial applications.
研究领域:
材料科学
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高分子科学
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纳米技术
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2016
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IF 4.425
Ting He,Huiqiong Wu,Xiaojuan Wang,Qiguang Zang,Peng Xue,Rujuan Shen,Li Dang,Yi Zhang,Juan Xiang
A facile strategy was developed to fabricate structure controllable microcrystals of ferrocene-based metal–organic (Fc-Ala-BCB) materials through evaporation-induced self-assembly. Two distinctive microcrystals, microrods and microtubes had been achieved by tuning the solvents during the self-assemblies. X-ray diffraction analysis was conducted on single crystals to investigate the packing mode of Fc-Ala-BCB molecules, which indicated the two crystals with the hexagonal system. Inheriting the aromaticity and chirality of ferrocenyl and l-Ala, this organic molecule self-assembled into a single-helix structure through intermolecule hydrogen bonds and π–π stacking. Theoretical analysis and stimulated computations were carried out to compare the surface energies of certain planes. Among those microcrystals, the microrods exhibited a higher chemical activity in catalyzing the decomposition of H2O2, due to the high-density atomic steps and kinks on the high energy surfaces. However, the hollow hexagonal tubes displayed appropriate catalytic activity and novel maneuverability toward catalyzing H2O2. The O2 bubbles accumulated at the inner walls of the microtube were periodically released as individual bubbles, suggesting their potential application as a new kind of microengine (e.g., the microrotor).
研究领域:
材料科学
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纳米技术
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化学工程
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2022
·Vol. 19
·期 2
·2205024
·
IF 15.153
Jundong Lin,Huikang Yang,Yixun Zhang,Fen Zou,Huichan He,Wenjie Xie,Zhihao Zou,Ren Liu,Qianfeng Xu,Jie Zhang,Guowei Zhong,Yuejiao Li,ZhenFeng Tang,Yulin Deng,Shanghua Cai,Linyao Wang,Yugang Huang,Yangjia Zhuo,Xinqing Jiang,Weide Zhong
Mono-chemotherapy has significant side effects and unsatisfactory efficacy, limiting its clinical application. Therefore, a combination of multiple treatments is becoming more common in oncotherapy. Chemotherapy combined with the induction of ferroptosis is a potential new oncotherapy. Furthermore, polymeric nanoparticles (NPs) can improve the antitumor efficacy and decrease the toxicity of drugs. Herein, a polymeric NP, mPEG -b- PPLGFc@Dox, is synthesized to decrease the toxicity of doxorubicin (Dox) and enhance the efficacy of chemotherapy by combining it with the induction of ferroptosis. First, mPEG -b- PPLGFc@Dox is oxidized by endogenous H 2 O 2 and releases Dox, which leads to an increase of H 2 O 2 by breaking the redox balance. The Fe(II) group of ferrocene converts H 2 O 2 into ·OH, inducing subsequent ferroptosis. Furthermore, glutathione peroxidase 4, a biomarker of ferroptosis, is suppressed and the lipid peroxidation level is elevated in cells incubated with mPEG -b- PPLGFc@Dox compared to those treated with Dox alone, indicating ferroptosis induction by mPEG -b- PPLGFc@Dox. In vivo, the antitumor efficacy of mPEG -b- PPLGFc@Dox is higher than that of free Dox. Moreover, the loss of body weight in mice treated mPEG -b- PPLGFc@Dox is lower than in those treated with free Dox, indicating that mPEG -b- PPLGFc@Dox is less toxic than free Dox. In conclusion, mPEG -b- PPLGFc@Dox not only has higher antitumor efficacy but it reduces the damage to normal tissue.
研究领域:
药学
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纳米技术
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肿瘤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）