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Photoresponsive α-Diimine Nickel Modulated Ethylene (Co)Polymerization

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Chinese Journal of Chemistry 2022年第24期40卷 2919-2926页

作者： Jingshuang Yang Xiaoqiang Hu zhongbao jian State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesRenmin Street 5625ChangchunJilin130022 China University of Science and Technology of China HefeiAnhui230026 China

Beyond the single ligand electronic and/or steric modifications, external stimuli are a useful tool for modulating catalytic polymerization reactions. Light stands out from external stimuli, but the corresponding photoresponsive transition metal catalysts are significantly rare for olefin polymerization due to the difficult synthesis. In this contribution, in consideration of the key role of steric shielding on the axial sites, we installed four concerted azobenzene moieties into symmetrically terphenyl-based α-diimine Ni(II) complexes to prepare photoresponsive catalysts, which were applied to ethylene polymerization and copolymerization with polar monomer. Via the trans-cis isomerization of azobenzene-functionalized Ni(II) catalysts in dark or under UV light, catalytic activity, polymer molecular weight, branching density, incorporation of co-monomer, and even the ratio of branching pattern were significantly modulated in ethylene (co)polymerizations. This photo-controlled strategy behaved an opposite influence between ethylene polymerization and copolymerization, in terms of catalytic activity and polymer molecular weight. As a result, slightly branched ultrahigh molecular weight polyethylenes and high molecular weight functionalized polyethylenes were produced at ambient conditions.

关键词： Olefin polymerization Photochemistry Polyethylene Polar monomer Nickel catalyst

Direct Synthesis of Ultrahigh Molecular Weight Functionalized Isotactic Polypropylene

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CCS Chemistry 2023年第11期5卷 2638-2649页

作者： Guanglin Zhou Hongliang Mu Xin Ma Xiaohui Kang zhongbao jian State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022 University of Science and Technology of China Hefei 230026 College of Pharmacy Dalian Medical UniversityDalian 116044

Ultrahigh molecular weight functionalized isotactic polypropylene(f-UHMW-iPP)through the direct copolymerization of propylene with polar monomers is highly desirable but has not been accessed thus far because it involves challenging regio-and stereochemistry along with usually reduced molecular weight.Herein,in contrast to the unsuccessful catalyst strategy,a polar monomer-assisted strategy is used to access the above material.The introduction of O-or S-functionalized long-chain polar olefins into the hafnium-catalyzed copolymerization of propylene(and bulkierα-olefins)significantly increases the copolymer molecular weight with a maximum observed increase of+488%.f-UHMW-iPP and functionalized isotactic poly(α-olefin)s(M_(w)>2000 kDa,[mmmm]:99%)are thus prepared at ambient conditions.The incorporation of 1 mol%of polar monomer improves the surface property and significantly increases the long-sought toughness(860%)of brittle iPP,without reducing the tensile strength(42 MPa)due to the key achievement of ultrahigh molecular weight.A discussion of the mechanism involved in the beneficial effects of incorporating the polar monomer is herein presented by an in-depth density functional theory calculation.

关键词： homogeneous catalysis olefin polymerization polar monomer ultrahigh molecular weight functionalized isotactic polypropylene

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

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CCS Chemistry 2022年第5期4卷 1680-1694页

作者： Xiaoqiang Hu Xiaohui Kang Yixin Zhang zhongbao jian State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022 University of Science and Technology of China Hefei 230026 College of Pharmacy Dalian Medical UniversityDalian 116044

The most straightforward and potentially ideal route to produce polar-functionalized polyethylene is direct copolymerization of ethylene with polar monomers.However,access to high-molecular-weight polar copolymers represents one of the biggest challenges in the field of olefin polymerization.In this contribution,we report a family of well-designed nickel catalysts that readily address this issue under convenient and highly desired ambient conditions.Under 1 bar at 30℃,polar-functionalized ultrahigh number-average molecular weight polyethylenes(UHMWPEs,Mn=0.83-1.10×10^(6) g mol^(−1))are directly generated.The highest average number of incorporated polar units per polymer chain is 122.This enhances copolymer molecular weights by two orders of magnitude relative to previous reports.Notably,this nickel catalyst family also exceptionally produces the highest number-average molecular weight polyethylenes(Mn=6.04×10^(6) g mol^(−1))at 1 bar.The Sterimol B1 steric parameter of nickel catalyst quantitatively correlates to polymer molecular weight.Mechanistic insights from density functional theory(DFT)calculation reveal that the low barrier(10.4 kcal mol^(−1))of ethylene insertion as the rate-limiting step should be responsible for high activity and the formation of UHMWPE.This coordination-insertion approach is a striking contrast to the high energy free-radical approach.

关键词： coordination polymerization functionalized UHMWPE homogeneous catalysis nickel catalyst polyolefin

Horizontally and Vertically Concerted Steric Strategy inα-Diimine Nickel Promoted Ethylene(Co)Polymerization

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Chinese Journal of Chemistry 2021年第10期39卷 2829-2836页

作者： Xiaoqiang Hu Yixin Zhang Baixiang Li zhongbao jian State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesRenmin Street 5625ChangchunJilin130022 China University of Science and Technology of China HefeiAnhui230026 China

Main observation and conclusion Steric bulk plays a significantly paramount role in late transition metal promoted olefin(co)polymerization in terms of polymer molecular weight and catalyst thermal stability.Numerous sterically encumbered nickel and palladium catalysts have been developed,but they are usually uni-directional.In this contribution,from a bi-directional side the distinctive horizontally and vertically concerted steric strategy was well-developed and applied toα-diimine nickel catalysts.In ethylene polymerization,the increase of vertically steric bulk(H,Ph,Biph)led to an enhanced polymer molecular weight,a slightly ascended branching density;likewise increasing horizontally steric bulk(Ph,Nap,Ant)further resulted in the increase of polymer molecular weight and branching density.As a result,in sharp contrast to Ni1(H)without steric bulk,Ni5(Ant)with horizontally and vertically concerted steric bulk was thermally stable,showed very high activities at a level of 107 g·mol–1·h^(–1),and produced polyethylenes with the highest molecular weight of 518.8×10^(4)g·mol^(-1)and the broader range of branching density from 2.4/1000C to 27.8/1000C.In the copolymerization of ethylene with methyl 10-undecenoate,Ni5(Ant)also provided the highest copolymer molecular weight but gave the lowest incorporation of co-monomer.This work sheds light on the steric effect on olefin(co)polymerization.

关键词： Olefin polymerization Steric effect Homogeneous catalysis UHMWPE Nickel

Macrocyclic Binuclearα-Diimine Nickel Catalysts for Ethylene Polymerization

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Chemical Research in Chinese Universities 2023年第5期39卷 797-802页

作者： YANG Jingshuang ZHANG Yuxing jian zhongbao State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026P.R.China

Polyolefins are globally important plastics.Molecular weight and molecular weight distribution are two key parameters for determining the properties of polyolefin materials.In this contribution,we develop a strategy for combining the macrocyclic framework and the binuclear effect into the benchmarkα-diimine late transition metal catalysts,and thus macrocyclic binuclearα-diimine nickel catalysts(Ni_(2)-Me and Ni_(2)-iPr)are prepared.Compared to the classical Brookhart's acyclic mononuclearα-diimine nickel analogues(Ni_(1)-Me and Ni_(1)-iPr),these nickel catalysts exhibit enhanced thermostability(up to 110℃)and produce polyethylenes with higher molecular weights(up to 7 times)and lower branching densities(as low as 9 branches/1000C)in methylaluminoxane(MAO)activated ethylene polymerization.This translates into the ability of the catalyst to afford more linear high molecular weight polyethylenes.In particular,bimodal polyethylenes with broad molecular weight distributions(Mw/Mn=8.08-14.66)are generated by the sole catalyst.This work affords diverse polyethylenes.

关键词： Polyolefin Nickel catalyst Diimine ligand Macrocyclic binuclear strategy Bimodal polyethylene

An Online Adaptive Internal Short Circuit Detection Method of Lithium-Ion Battery

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Automotive Innovation 2021年第1期4卷 93-102页

作者： jian Hu zhongbao Wei Hongwen He National Engineering Laboratory of Electric Vehicles School of Mechanical EngineeringBeijing Institute of Technology5 ZhongGuanCun South StreetHaidian DistrictBeijing 100181China

Internal short circuit(ISC)is a critical cause for the dangerous thermal runaway of lithium-ion battery(LIB);thus,the accurate early-stage detection of the ISC failure is critical to improving the safety of electric vehicles.In this paper,a model-based and self-diagnostic method for online ISC detection of LIB is proposed using the measured load current and terminal voltage.An equivalent circuit model is built to describe the characteristics of ISC cell.A discrete-time regression model is formulated for the faulty cell model through the system transfer function,based on which the electrical model parameters are adapted online to keep the model accurate.Furthermore,an online ISC detection method is exploited by incorporating an extended Kalman filter-based state of charge estimator,an abnormal charge depletion-based ISC current estimator,and an ISC resistance estimator based on the recursive least squares method with variant forgetting factor.The proposed method shows a self-diagnostic merit relying on the single-cell measurements,which makes it free from the extra uncertainty caused by other cells in the system.Experimental results suggest that the online parameterized model can accurately predict the voltage dynamics of LIB.The proposed diagnostic method can accurately identify the ISC resistance online,thereby contributing to the early-stage detection of ISC fault in the LIB.

关键词： Lithium-ion battery Internal short circuit Recursive least squares Extended Kalman filter

Secondary sclerosing cholangitis from percutaneous transhepatic biliary drainage in a patient with gallbladder cancer after surgery: A case report

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Journal of Interventional Medicine 2020年第1期3卷 58-59页

作者： zhongbao Tan Qingqing Wang Xuequn Mao Rong Zou jian Zhang Zhenhai Di Huanjing Wang Department of Interventional Radiology Affiliated Hospital of Jiangsu UniversityJiangsu212001China

Secondary sclerosing cholangitis(SSC)is a chronic cholestatic liver disease characterized by fibrosis and stricture of the bile ducts.SSC in association with multiple factors such as spontaneous choledochoduodenal fistula and metastatic gallbladder cancer has rarely been reported.However,to the best of our knowledge,reports of SSC after percutaneous transhepatic biliary drainage(PTBD),especially in cases with diffuse calcification of the bile duct walls,have not been reported.We report a case of SSC from PTBD in a patient with gallbladder cancer after surgery.The patient underwent external percutaneous biliary drainage for malignant bile duct obstruction after cholecystectomy.Repeated exchanges were performed at the first and the sixth month after PTBD using an internal and external drainage catheter.Two months after the third catheter exchange,findings of laboratory and imaging examinations were suggestive of SSC.The liver function tests of the patient were suggestive of cholestasis.Multidetector computed tomography showed diffuse calcification of the bile duct walls.Cholangiography showed intrahepatic biliary stenosis or dilatation.

关键词： patient biliary percutaneous

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空间位阻与氟效应协同增强镍系乙烯聚合

化学学报 2022年第6期80卷 741-747页

作者：王玉银胡小强穆红亮夏艳迟悦简忠保长春工业大学化学与生命科学学院高等材料研究院长春130012 长春工业大学材料科学与工程学院先进结构材料教育部重点实验室长春130012 中国科学院长春应用化学研究所高分子物理与化学国家重点实验室长春130022

烯烃聚合在工业上是最重要的化学反应之一.过渡金属催化剂是烯烃聚合反应发展的核心,其中水杨醛亚胺后过渡金属中性镍催化剂由于杂质耐受性强与无需助催化剂的双重优势备受青睐.为增强镍催化剂的催化性能,空间位阻效应或者氟效应策略已... 详细信息

烯烃聚合在工业上是最重要的化学反应之一.过渡金属催化剂是烯烃聚合反应发展的核心,其中水杨醛亚胺后过渡金属中性镍催化剂由于杂质耐受性强与无需助催化剂的双重优势备受青睐.为增强镍催化剂的催化性能,空间位阻效应或者氟效应策略已有广泛报道;然而将两者结合形成协同策略仍鲜有研究.在本工作中,对位氢和空间位阻取代基(苯基、萘基和蒽基)与邻位氟取代基被同时引入至水杨醛亚胺中性镍催化剂中,利用空间位阻效应与氟效应来协同增强镍系乙烯聚合.系统研究空间位阻效应、氟效应、聚合反应温度、聚合时间对乙烯聚合反应的活性、分子量、支化度的影响.结果表明,邻位氟取代基显著提升活性、催化剂寿命与聚合物分子量,降低聚合物支化度;对位空间位阻取代基的体积根据催化活性或聚合物分子量的需求而定,但对聚合物支化度几乎无影响.本工作发展了一种新的调控水杨醛亚胺镍烯烃聚合催化剂手段.

关键词：烯烃聚合氟效应空间位阻镍催化剂水杨醛亚胺

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Measurement of the relative neutron sensitivity curve of a LaBr_(3)(Ce)scintillator based on the CSNS Back-n white neutron source

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Chinese Physics B 2023年第10期32卷 66-72页

作者：刘建王东明甫跃成李忠宝易晗易龙涛 Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621900China Spallation Neutron Source Science Center Dongguan 523803China

A scintillator detector consisting of a LaBr_(3)(Ce)(0.5%)scintillator,a photomultiplier tube(PMT),and an oscilloscope were used to study the neutron sensitivities of the LaBr_(3)(Ce)scintillator at the China Spallation Neutron Source(CSNS)Back-n white neutron source in the double-bunch and single-bunch operation modes,respectively.Under the two operational modes,the relative neutron sensitivity curves of the LaBr_(3)(Ce)scintillator in the energy regions of 1–20 MeV and 0.5–20 MeV were obtained for the first time.In the energy range of 1–20 MeV,the two curves were nearly identical.However the relative neutron sensitivity uncertainties of the double-bunch experiment were higher than those of the single-bunch experiment.The above results indicated that the single-bunch experiment's neutron sensitivity curve has a lower minimum measurable energy than the double-bunch experiment.Above the minimum measurable energy of the double-bunch experiment,there is little difference between the measured relative neutron sensitivity curves of the single-bunch and double-bunch experiments of the LaBr_(3)(Ce)scintillator and those of other scintillators with a similar neutron response signal intensity.

关键词： relative neutron sensitivity LaBr_(3)(Ce) China Spallation Neutron Source(CSNS) white neutron source

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