期刊文献+
共找到32,954篇文章
< 1 2 250 >
每页显示 20 50 100
Interfacial reinforcement of core-shell HMX@energetic polymer composites featuring enhanced thermal and safety performance
1
作者 Binghui Duan Hongchang Mo +3 位作者 Bojun Tan Xianming Lu Bozhou Wang Ning Liu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期387-399,共13页
The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves... The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves the pretreatment of HMX to endow—OH groups on the surface via polyalcohol bonding agent modification and in situ coating with nitrate ester-containing polymer,was proposed to address the problem.Two types of energetic polyether—glycidyl azide polymer(GAP)and nitrate modified GAP(GNP)were grafted onto HMX crystal based on isocyanate addition reaction bridged through neutral polymeric bonding agent(NPBA)layer.The morphology and structure of the HMX-based composites were characterized in detail and the core-shell structure was validated.The grafted polymers obviously enhanced the adhesion force between HMX crystals and fluoropolymer(F2314)binder.Due to the interfacial reinforcement among the components,the two HMX-based composites exhibited a remarkable increment of phase transition peak temperature by 10.2°C and 19.6°C with no more than 1.5%shell content,respectively.Furthermore,the impact and friction sensitivity of the composites decreased significantly as a result of the barrier produced by the grafted polymers.These findings will enhance the future prospects for the interface design of energetic composites aiming to solve the weak interface and safety concerns. 展开更多
关键词 HMX crystals Polyalcohol bonding agent Energetic polymer core-shell structure Interfacial reinforcement
下载PDF
Synthesis of Core-shell ZSM-5@ Ordered Mesoporous Silica by Tetradecylamine Surfactant
2
作者 马扩彦 ZHAO Pengxian +4 位作者 YI Hongyu 俞海军 ZHOU Moxi ZHANG Lingling LIU Yupu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期332-336,共5页
A core-shell composite consisting of ZSM-5 zeolite as the core and ordered mesoporous silica as the shell was prepared by a surfactant-controlled sol-gel process and using tetradecylamine(TDA) as the template and Tetr... A core-shell composite consisting of ZSM-5 zeolite as the core and ordered mesoporous silica as the shell was prepared by a surfactant-controlled sol-gel process and using tetradecylamine(TDA) as the template and Tetraethylorthosilicate(TEOS) as the silica precursor.The pores of the silica shell were found to be ordered and perpendicular to the crystal faces of the zeolite core.The thickness of the shell in the coreshell structured composite can be adjusted in the range of 20-90 nm,while the surface morphology and the pore size distribution were modified by changing the mass ratio of TEOS to zeolite.The composite molecular sieves have higher surface area for capturing molecules than ZSM-5,and with the increase of mesoporous shell layer,the ZSM-5@SiO_(2)-x composites show stronger adsorption capacity of butyraldehyde.However,when the shell thickness exceeds 90 nm,the adsorption capacity of butyraldehyde decreases instead.The composites have a huge potential for environmental applications. 展开更多
关键词 core-shell COMPOSITE tetradecylamine SURFACTANT ADSORPTION
下载PDF
Carbon nanotube-hyperbranched polymer core-shell nanowires with highly accessible redox-active sites for fast-charge organic lithium batteries 被引量:1
3
作者 Zhonghui Sun Meng Shu +4 位作者 Jiabin Li Bing Liu Hongyan Yao Shaowei Guan Zhenhua Sun 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第3期30-36,I0002,共8页
Organic electrode materials are promising for lithium-ion batteries(LIBs) because of their environmental friendliness and structural diversity.However,they always suffer from limited capacity,poor cycling stability,an... Organic electrode materials are promising for lithium-ion batteries(LIBs) because of their environmental friendliness and structural diversity.However,they always suffer from limited capacity,poor cycling stability,and rate performance.Herein,hexaazatrinaphthalene-based azo-linked hyperbranched polymer(HAHP) is designed and synthesized as a cathode for LIBs.However,the densely stacked morphology lowers the chance of the active sites participating in the redox reaction.To address this issue,the singlewalled carbon nanotube(SWCNT) template is used to induce the growth of nanosized HAHP on the surface of SWCNTs.The HAHP@SWCNT nanocomposites have porous structures and highly accessible active sites.Moreover,the strong π-π interaction between HAHP and highly conductive SWCNTs effectively endows the HAHP@SWCNT nanocomposites with improved cycling stability and fast charge-discharge rates.As a result,the HAHP@SWCNT nanocomposite cathode shows a high specific capacity(320.4 mA h g^(-1)at 100 mA g^(-1)),excellent cycling stability(800 cycles;290 mA h g^(-1)at 100 mA g^(-1),capacity retained 91%) and outstanding rate performance(235 mA h g^(-1)at 2000 mA g^(-1),76% capacity retention versus 50 mA g^(-1)).This work provides a strategy to combine the macromolecular structural design and micromorphology control of electrode materials for obtaining organic polymer cathodes for high-performance LIBs. 展开更多
关键词 Organic electrode Organic lithium batteries core-shell nanowire Hexaazatrinaphthylene polymer electrode materials
下载PDF
Core-Shell Semiconductor-Graphene Nanoarchitectures for Efficient Photocatalysis:State of the Art and Perspectives
4
作者 Jinshen Lan Shanzhi Qu +6 位作者 Xiaofang Ye Yifan Zheng Mengwei Ma Shengshi Guo Shengli Huang Shuping Li Junyong Kang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期553-588,共36页
Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and str... Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields. 展开更多
关键词 core-shell semiconductor-graphene Nanoarchitecture PHOTOCATALYSIS Driving force Interface
下载PDF
Recent advances in core-shell organic framework-based photocatalysts for energy conversion and environmental remediation
5
作者 Qibing Dong Ximing Li +9 位作者 Yanyan Duan Qingyun Tian Xinxin Liang Yiyin Zhu Lin Tian Junjun Wang Atif Sial Yongqian Cui Ke Zhao Chuanyi Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期168-199,I0004,共33页
Direct conversion of solar energy into chemical energy in an environmentally friendly manner is one of the most promising strategies to deal with the environmental pollution and energy crisis.Among a variety of materi... Direct conversion of solar energy into chemical energy in an environmentally friendly manner is one of the most promising strategies to deal with the environmental pollution and energy crisis.Among a variety of materials developed as photocatalysts,the core-shell metal/covalent-organic framework(MOF or COF)photocatalysts have garnered significant attention due to their highly porous structure and the adjustability in both structure and functionality.The existing reviews on core-shell organic framework photocatalytic materials have mainly focused on core-shell MOF materials.However,there is still a lack of indepth reviews specifically addressing the photocatalytic performance of core-shell COFs and MOFs@COFs.Simultaneously,there is an urgent need for a comprehensive review encompassing these three types of core-shell structures.Based on this,this review aims to provide a comprehensive understanding and useful guidelines for the exploration of suitable core-shell organic framework photocatalysts towards appropriate photocatalytic energy conversion and environmental governance.Firstly,the classification,synthesis,formation mechanisms,and reasonable regulation of core-shell organic framework were summarized.Then,the photocatalytic applications of these three kinds of core-shell structures in different areas,such as H_(2)evolution,CO_(2)reduction,and pollutants degradation are emphasized.Finally,the main challenges and development prospects of core-shell organic framework photocatalysts were introduced.This review aims to provide insights into the development of a novel generation of efficient and stable core-shell organic framework materials for energy conversion and environmental remediation. 展开更多
关键词 Organic framework core-shell structure PHOTOCATALYSIS Energy conversion Environmental remediation
下载PDF
Lithium Salt Combining Fluoroethylene Carbonate Initiates Methyl Methacrylate Polymerization Enabling Dendrite-Free Solid-State Lithium Metal Battery
6
作者 Xue Ye Jianneng Liang +6 位作者 Baorong Du Yongliang Li Xiangzhong Ren Dazhuan Wu Xiaoping Ouyang Qianling Zhang Jianhong Liu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期50-59,共10页
This work demonstrates a novel polymerization-derived polymer electrolyte consisting of methyl methacrylate,lithium bis(trifluoromethanesulfonyl)imide and fluoroethylene carbonate.The polymerization of MMA was initiat... This work demonstrates a novel polymerization-derived polymer electrolyte consisting of methyl methacrylate,lithium bis(trifluoromethanesulfonyl)imide and fluoroethylene carbonate.The polymerization of MMA was initiated by the amino compounds following an anionic catalytic mechanism.LiTFSI plays both roles including the initiator and Li ion source in the polymer electrolyte.Normally,lithium bis(trifluoromethanesulfonyl)imide has difficulty in initiating the polymerization reaction of methyl methacrylate monomer,a very high concentration of lithium bis(trifluoromethanesulfonyl)imide is needed for initiating the polymerization.However,the fluoroethylene carbonate additive can work as a supporter to facilitate the degree of dissociation of lithium bis(trifluoromethanesulfonyl)imide and increase its initiator capacity due to the high dielectric constant.The as-prepared poly-methyl methacrylate-based polymer electrolyte has a high ionic conductivity(1.19×10^(−3)S cm^(−1)),a wide electrochemical stability window(5 V vs Li^(+)/Li),and a high Li ion transference number(t_(Li^(+)))of 0.74 at room temperature(RT).Moreover,this polymerization-derived polymer electrolyte can effectively work as an artificial protective layer on Li metal anode,which enabled the Li symmetric cell to achieve a long-term cycling performance at 0.2 mAh cm^(−2)for 2800 h.The LiFePO_(4)battery with polymerization-derived polymer electrolyte-modified Li metal anode shows a capacity retention of 91.17%after 800 cycles at 0.5 C.This work provides a facile and accessible approach to manufacturing poly-methyl methacrylate-based polymerization-derived polymer electrolyte and shows great potential as an interphase in Li metal batteries. 展开更多
关键词 in situ polymerization lithium anode polymer electrolyte solid-state lithium batteries
下载PDF
A novel Ag/ZnO core-shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals
7
作者 Wenmei Han Wenli Wang +4 位作者 Jie Fan Runping Jia Xuchun Yang Tong Wu Qingsheng Wu 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第2期366-377,共12页
The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by ... The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance. 展开更多
关键词 Ag/ZnO hollow core-shell structures ANTIBIOTICS GENTAMYCIN Synergistic sterilization PHOTODEGRADATION
下载PDF
Exploring the Core-shell Structure of BaTiO3-based Dielectric Ceramics Using Machine Learning Models and Interpretability Analysis
8
作者 孙家乐 XIONG Peifeng +1 位作者 郝华 LIU Hanxing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期561-569,共9页
A machine learning(ML)-based random forest(RF)classification model algorithm was employed to investigate the main factors affecting the formation of the core-shell structure of BaTiO_(3)-based ceramics and their inter... A machine learning(ML)-based random forest(RF)classification model algorithm was employed to investigate the main factors affecting the formation of the core-shell structure of BaTiO_(3)-based ceramics and their interpretability was analyzed by using Shapley additive explanations(SHAP).An F1-score changed from 0.8795 to 0.9310,accuracy from 0.8450 to 0.9070,precision from 0.8714 to 0.9000,recall from 0.8929 to 0.9643,and ROC/AUC value of 0.97±0.03 was achieved by the RF classification with the optimal set of features containing only 5 features,demonstrating the high accuracy of our model and its high robustness.During the interpretability analysis of the model,it was found that the electronegativity,melting point,and sintering temperature of the dopant contribute highly to the formation of the core-shell structure,and based on these characteristics,specific ranges were delineated and twelve elements were finally obtained that met all the requirements,namely Si,Sc,Mn,Fe,Co,Ni,Pd,Er,Tm,Lu,Pa,and Cm.In the process of exploring the structure of the core-shell,the doping elements can be effectively localized to be selected by choosing the range of features. 展开更多
关键词 machine learning BaTiO_(3) core-shell structure random forest classifier
下载PDF
Core-shell mesoporous carbon hollow spheres as Se hosts for advanced Al-Se batteries
9
作者 Haiping Lei Tianwei Wei +1 位作者 Jiguo Tu Shuqiang Jiao 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期899-906,共8页
Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery performance.However,the cycling stability of Se positive electrodes has challen... Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery performance.However,the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction products.In this work,we aim to harness the advantages of Se while reducing its limitations by preparing a core-shell mesoporous carbon hollow sphere with a titanium nitride(C@TiN)host to load 63.9wt%Se as the positive electrode material for Al-Se batteries.Using the physical and chemical confinement offered by the hollow mesoporous carbon and TiN,the obtained core-shell mesoporous carbon hollow spheres coated with Se(Se@C@TiN)display superior utilization of the active material and remarkable cycling stability.As a result,Al-Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g^(-1)at a current density of 1000 mA·g^(-1)while maintaining a discharge specific capacity of 86.0 mAh·g^(-1)over 200 cycles.This improved cycling performance is ascribed to the high electrical conductivity of the core-shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN. 展开更多
关键词 aluminum-selenium batteries intermediate products core-shell mesoporous carbon hollow sphere cycling performance
下载PDF
Efficient in-situ end-functionalization of polydienes by isothiocyanate via neodymium mediated coordinative chain transfer polymerization system
10
作者 ZHANG Xiu-hui DONG Jing +2 位作者 WANG Feng LIU Heng ZHANG Xue-quan 《合成橡胶工业》 CAS 2024年第4期347-347,共1页
End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerizatio... End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerization systems,it is highly challenging to achieve such end-functionalizations,because most of polydienyl chains are capped withη3-allyl-Nd moiety during the end of polymerization,which shows very poor reactivity with nucleophile compounds.We launched a new diene polymerization strategy calling coordinative chain transfer polymerization(CCTP)[1].In such a system,all the polydienyl chains are capped withη1-allyl-Al moieties,which reveal greater reactivity with cyclic esters and epoxide compounds,providing an effective manner to prepare polydiene-polyester amphiphilic block copolymers.Inspired by such findings,we now show herein how such types of chain-ends react with isot-hiocyanate to demonstrate an efficient in-situ manner to access end-functionalized polydienes by using CCTP. 展开更多
关键词 properties. polymerization NEODYMIUM
下载PDF
Influence of external nitrogen-containing donors on polymerization behavior of neodymium-based cis-1,4-polybutadiene rubber
11
作者 LI Xin DONG Jing +3 位作者 HAN Zhuo-ling WANG Feng ZHANG Xue-quan LIU Heng 《合成橡胶工业》 CAS 2024年第5期438-438,共1页
Neodymium(Nd)-based catalyst in butadiene(Bd)polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal(Ti,Co,Ni,etc.)-based catalysts[1-2].Such outst... Neodymium(Nd)-based catalyst in butadiene(Bd)polymerization has drawn interests due to its availability in affording higher cis-1,4-unit selectivity than transition metal(Ti,Co,Ni,etc.)-based catalysts[1-2].Such outstanding high cis-1,4-unit selecti-vity is hypothetically originated from the presence of 4 f orbitals,that can participate in monomer coordination and thereby govern subsequent enchainment manners.This unique characteristic also renders the active species highly susceptible to Lewis bases,and may impact the overall selectivity as well as polyme-rization behavior after coordination.Nevertheless,it is still a virgin area in such a field,and the influence of Lewis bases on Nd-based diene polymerizations is still a black box.Based on this consideration,how nitrogen-containing donors(D)impacts the overall behaviors of Nd-mediated Bd polymerizations is disclosed. 展开更多
关键词 polymerization BASES SELECTIVITY
下载PDF
Fe-N_(x) sites coupled with core-shell FeS@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries
12
作者 Katam Srinivas Zhuo Chen +3 位作者 Anran Chen Fei Ma Ming-qiang Zhu Yuanfu Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期565-577,I0013,共14页
The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To ad... The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies. 展开更多
关键词 Fe-N_(x)sites core-shell FeS@C Synergistic interactions Oxygen reduction reaction Zn-air battery
下载PDF
Synergistic Tuning of Nickel Cobalt Selenide@Nickel Telluride Core-Shell Heteroarchitectures for Boosting Overall Urea Electrooxidation and Electrochemical Supercapattery
13
作者 Diab Khalafallah Weibo Huang +1 位作者 Mingjia Zhi Zhanglian Hong 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第1期301-312,共12页
Herein,we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride(Ni_(x)Co_(12-x)Se@NiTe)core-shell heterostructures via an electrodeposition approach for overall urea electrolysis and superc... Herein,we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride(Ni_(x)Co_(12-x)Se@NiTe)core-shell heterostructures via an electrodeposition approach for overall urea electrolysis and supercapacitors.The 3D vertically orientated NiTe dendritic frameworks induce the homogeneous nucleation of 2D Ni_(x)Co_(12-x)Se nanosheet arrays along similar crystal directions and bring a strong interfacial binding between the integrated active components.In particular,the optimized Ni_(6)Co_(6)Se@NiTe with an interface coupling effect works in concert to tune the intrinsic activity.It only needs a low overpotential of 1.33 V to yield a current density of 10 mA cm^(-2)for alkaline urea electrolysis.Meanwhile,the full urea catalysis driven only by Ni_(6)Co_(6)Se@NiTe achieves 10 mA cm^(-2)at a potential of 1.38 V and can approach a constant level of the current response for 40 h.Besides,the integrated Ni_(6)Co_(6)Se@NiTe electrode delivers an enhanced specific capacity(223 mA h g^(-1)at 1 A g^(-1))with a high cycling stability.Consequently,a hybrid asymmetric supercapacitor(HASC)device based on Ni_(6)Co_(6)Se@NiTe exhibits a favorable rate capability and reaches a high energy density of 67.7 Wh kg^(-1)and a power density of 724.8 W kg^(-1)with an exceptional capacity retention of 92.4%after sequential 12000 cycles at 5 A g^(-1). 展开更多
关键词 bifunctional Ni_(x)Co_(12-x)Se@NiTe core-shell electrodeposition heterointerfaces supercapacitors UOR
下载PDF
Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption
14
作者 Xiaoyu Chen 《Journal of Renewable Materials》 EI CAS 2024年第4期815-826,共12页
A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calci... A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the core.Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate.Scanning electron microscopy images showed the core-shell structure.The core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the core.During the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the core.Adsorption tests showed that the coreshell structure had a larger adsorption capacity than the core alone.The shell effectively enhanced the adsorption capacity to methylene blue compared to the single core.Methylene blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed. 展开更多
关键词 core-shell structure hydrogel bead attapulgite nanofiber sodium alginate POLYACRYLAMIDE methylene blue adsorption material
下载PDF
Nickel catalysts with asymmetric steric hindrance for ethylene polymerization
15
作者 Wanlu Tian Fuzhou Wang Chen Zou 《中国科学技术大学学报》 CAS CSCD 北大核心 2024年第6期48-52,59,I0010,I0011,共8页
α-Diimide catalysts have attracted widespread attention due to their unique chain walking characteristics.A series ofα-diimide nickel/palladium catalysts with different electronic effects and steric hindrances were ... α-Diimide catalysts have attracted widespread attention due to their unique chain walking characteristics.A series ofα-diimide nickel/palladium catalysts with different electronic effects and steric hindrances were designed and synthesized for olefin polymerization.In this work,we synthesized a series of asymmetricα-diimide nickel complexes with different steric hindrances and used them for ethylene polymerization.These nickel catalysts have high ethylene polymerization activity,up to 6.51×10^(6)g·mol^(−1)·h^(−1),and the prepared polyethylene has a moderate melting point and high molecular weight(up to 38.2×10^(4)g·mol^(−1)),with a branching density distribution between 7 and 94 branches per 1000 carbons.More importantly,the polyethylene prepared by these catalysts exhibits excellent tensile properties,with strain and stress reaching 800%and 30 MPa,respectively. 展开更多
关键词 Α-DIIMINE nickel complex POLYETHYLENE polymerization asymmetric steric hindrance
下载PDF
3D printing encouraging desired in-situ polypyrrole seed-polymerization for ultra-high energy density supercapacitors
16
作者 Tiantian Zhou Shangwen Ling +6 位作者 Shuxian Sun Ruoxin Yuan Ziqin Wu Mengyuan Fu Hanna He Xiaolong Li Chuhong Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期117-125,I0004,共10页
The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly co... The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly conductive polymer and a prospective pseudocapacitive materials for supercapacitors,yet the inferior cyclic stability and unpredictable polymerization patterns severely impede its real-world applicability.Here,for the first time,an innovative seed-induced in-situ polymerization assisted 3D printing strategy is proposed to fabricate PPy-reduced graphene oxide/poly(vinylidene difluoride-cohexafluoropropylene)(PVDF-HFP)(PPy-rGO/PH)electrodes with controllable polymerization behavior and exceptional areal mass loading.The preferred active sites uniformly pre-planted on the 3D-printed graphene substrates serve as reliable seeds to induce efficient polypyrrole deposition,achieving an impressive mass loading of 185.6 mg cm^(-2)(particularly 79.2 mg cm^(-2)for polypyrrole)and a superior areal capacitance of 25.2 F cm^(-2)at 2 mA cm^(-2)for a 12-layer electrode.In agreement with theses appealing features,an unprecedented areal energy density of 1.47 mW h cm^(-2)for a symmetrical device is registered,a rarely achieved value for other PPy/rGO-based supercapacitors.This work highlights a promising route to preparing high energy density energy storage modules for real-world applications. 展开更多
关键词 3D printing Seed-induced polymerization SUPERCAPACITOR POLYPYRROLE High energy density
下载PDF
Two-photon polymerization lithography for imaging optics
17
作者 Hao Wang Cheng-Feng Pan +16 位作者 Chi Li Kishan S Menghrajani Markus A Schmidt Aoling Li Fu Fan Yu Zhou Wang Zhang Hongtao Wang Parvathi Nair Suseela Nair John You En Chan Tomohiro Mori Yueqiang Hu Guangwei Hu Stefan A Maier Haoran Ren Huigao Duan Joel K W Yang 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第4期21-60,共40页
Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio fre... Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives.Traditional glass lenses are fabricated through a series of complex processes,while polymers offer versatility and ease of production.However,modern applications often require complex lens assemblies,driving the need for miniaturization and advanced designs with micro-and nanoscale features to surpass the capabilities of traditional fabrication methods.Three-dimensional(3D)printing,or additive manufacturing,presents a solution to these challenges with benefits of rapid prototyping,customized geometries,and efficient production,particularly suited for miniaturized optical imaging devices.Various 3D printing methods have demonstrated advantages over traditional counterparts,yet challenges remain in achieving nanoscale resolutions.Two-photon polymerization lithography(TPL),a nanoscale 3D printing technique,enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin.It offers unprecedented abilities,e.g.alignment-free fabrication,micro-and nanoscale capabilities,and rapid prototyping of almost arbitrary complex 3D nanostructures.In this review,we emphasize the importance of the criteria for optical performance evaluation of imaging devices,discuss material properties relevant to TPL,fabrication techniques,and highlight the application of TPL in optical imaging.As the first panoramic review on this topic,it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics,promoting a deeper understanding of the field.By leveraging on its high-resolution capability,extensive material range,and true 3D processing,alongside advances in materials,fabrication,and design,we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications. 展开更多
关键词 two-photon polymerization lithography 3D printing additive manufacturing IMAGING optics and nanophotonics
下载PDF
Effect of solvent on the initiation mechanism of living anionic polymerization of styrene:A computational study
18
作者 Shen Li Yin-Ning Zhou +1 位作者 Zhong-Xin Liu Zheng-Hong Luo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期135-142,共8页
For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of sol... For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and kinetics.In this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic modeling.In terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules.Furthermore,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient.Counterintuitively,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic modeling.It is found that in benzene and n-pentane,the polymerization rate exhibits first-order kinetics.While,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics. 展开更多
关键词 Living anionic polymerization Solvent effect Reaction kinetics Computational chemistry Mathematical modeling Kinetic modeling
下载PDF
Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization
19
作者 Zhengquan Dong Pei Li +1 位作者 Guoyong Xu Fuzhou Wang 《Open Journal of Organic Polymer Materials》 2024年第1期1-12,共12页
The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, ... The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature. 展开更多
关键词 Ethylene polymerization α-Diimine Ni(II) Complex Chain-Walking polymerization Branched Polyethylene
下载PDF
Synthesis and Characterization of Poly Styrene-Co-Poly 2-Hydroxyethylmethacrylate (HEMA) Copolymer and an Investigation of Free-Radical Copolymerization Propagation Kinetics by Solvent Effects
20
作者 Anaif M. Alhewaitey Ishrat Khan Naif M. Alhawiti 《Open Journal of Polymer Chemistry》 2024年第1期63-93,共31页
A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The sa... A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (<sup>1</sup>H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an amphiphilic copolymer with diverse characteristics. A plausible explanation underlying our observations is that the reaction conditions employed in the synthesis of these copolymers might not be the right route required under free radical polymerization. 展开更多
关键词 2-Hydroxyethyl Methacrylate polymerization
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部