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SYNTHESIS OF TRIBLOCK COPOLYMERS OF STYRENE AND ISOPRENE BY A NITROXIDE-MEDIATED LIVING FREE RADICAL POLYMERIZATION 被引量:2
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作者 P. Najafi Mogaddam A. Entezami 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2004年第1期55-61,共7页
The controlled free radical polymerization of styrene and isoprene initiated with benzoyl peroxide (BPO) in the presence of 2,2,6,6-tetramethyl piperidine-N-oxyl (TEMPO) at 125 'C were performed. The obtained poly... The controlled free radical polymerization of styrene and isoprene initiated with benzoyl peroxide (BPO) in the presence of 2,2,6,6-tetramethyl piperidine-N-oxyl (TEMPO) at 125 'C were performed. The obtained polyisoprene and polystyrene homopolymers served as macroinitiators for block copolymerization of isoprene and styrene to synthesize poly- (styrene-b-isoprene) and poly(isoprene-b-styrene) diblock copolymers. Diblock copolymers with well-defined structures as well as controlled and narrow molecular weight distribution were obtained from the lower-mass polystyrene and polyisoprene homopolymers. These copolymers were found to be active as macroinitiators in the synthesis of the poly(styrene-b-isoprene-b-styrene) and poly(isoprene-b-styrene-b-isoprene) triblock copolymers. 1H-NMR spectroscopy and gel permeation chromatography (GPC) were used for the investigation of polymer structure, molecular weight and polydispersity (PD). 展开更多
关键词 Diblock and triblock copolymer Controlled radical polymerization TEMPO Polystyrene POLYISOPRENE
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Effect of spacer length on the liquid crystalline property of azobenzene-containing ABA-type triblock copolymers via ATRP 被引量:2
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作者 Xin De Tang Long Cheng Gao +1 位作者 Xing He Fan Qi Feng Zhou 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第9期1129-1132,共4页
The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated. For the study, the monomers, n-[4-(4-ethoxyphenylazo)phenoxy]alkyl... The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated. For the study, the monomers, n-[4-(4-ethoxyphenylazo)phenoxy]alkyl methacrylates with varying methylene groups (n = 0, 2, 6) were used to synthesize a series of azobenzene-containing amphiphilic triblock copolymers PAnC–PEG–PAnC by atom transfer radical polymerization (ATRP). Differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and one-dimensional X-ray diffraction (1D WAXD) have shown that the glass transition temperatures of these copolymers decreased with increasing n, PA0C–PEG–PA0C has no mesophase, while both PA2C–PEG–PA2C and PA6C–PEG–PA6C have a nematic mesophase. These differences derive from the length of spacer groups between the polymer backbone and side-chain LC monomers. 展开更多
关键词 Spacer group Liquid crystalline property AZOBENZENE triblock copolymer Atom transfer radical polymerization (ATRP)
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SYNTHESIS AND CHARACTERIZATION OF POLY(AMINO ACID-UREA)S COMPRISING NOVEL TRIBLOCK COPOLYMERS OF POLY(TETRAHYDROFURAN)AND POLY(γ-BENZYL L-GLUTAMATE)S 被引量:1
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作者 冯增国 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第3期317-325,共9页
A kind of novel triblock copolymers of poly(γ-benzyl L-glutamate)-b-poly(tetrahydrofuran)-b-poly(γ-benzyl L-glutamate)s(PBLG-b-PTHF-b-PBLG)was synthesized by using bis(3-aminopropyl)terminated polytetrahydrofuran to... A kind of novel triblock copolymers of poly(γ-benzyl L-glutamate)-b-poly(tetrahydrofuran)-b-poly(γ-benzyl L-glutamate)s(PBLG-b-PTHF-b-PBLG)was synthesized by using bis(3-aminopropyl)terminated polytetrahydrofuran to initiate the ring-opening polymerization ofγ-benzyl L-glutamate N-carboxyanhydride(BLG-NCA).The corresponding multiblock poly(amino acid-urea)s were prepared in one-pot protocol from the chain extension of PBLG-b-PTHF-b-PBLG with MDI.The resulting triblock and multiblock copolymers were characterized by FTIR,~1H-NMR,^(13)C-NMR and GPC techniques.It is demonstrated that the chain extension has taken place to give rise to the copolymers with the well-defined block composition and narrow molecular weight distribution.A distinct T_g arising from the hard-segments was observed in all the copolymers.Their mechanical properties showed an increasing trend with the molecular weight enhancement of the prepolymers. 展开更多
关键词 Polyurethane POLYPEPTIDE triblock copolymer Ring-opening polymerization.
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Monte Carlo Simulation for the Adsorption of Symmetric Triblock Copolymers 被引量:1
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作者 彭昌军 李健康 +1 位作者 刘洪来 胡英 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第3期357-362,共6页
The adsorption behavior of symmetric triblock copolymers, Am/2BnAm/2, from a nonselective solvent at solid-liquid interface has been studied by Monte Carlo simulations on a simple lattice model. Either segment A or se... The adsorption behavior of symmetric triblock copolymers, Am/2BnAm/2, from a nonselective solvent at solid-liquid interface has been studied by Monte Carlo simulations on a simple lattice model. Either segment A or segment B is attractive, while the other is non-attractive to the surface. Influences of the adsorption energy, bulk concentration, chain composition and chain length on the microstructure of adsorbed layers are presented. The results show that the total surface coverage and the adsorption amount increases monotonically as the bulk concentration increases. The larger the adsorption energy and the higher the fraction of adsorbing segments, the higher the total surface coverage is exhibited. The product of surface coverage and the proportion of non-attractive segments are nearly independent of the chain length, and the logarithm of the adsorption amount is a linear function of the reciprocal of the reduced temperature. When the adsorption energy is larger, the adsorption amount exhibits a maximum as the fraction of adsorbing segment increases. The adsorption isotherms of copolymers with different length of non-attractive segments can be mapped onto a single curve under given adsorption energy. The adsorption layer thickness decreases as the adsorption energy and the fraction of adsorbing segments increases, but it increases as the length of non-attractive segments increases. The tails mainly govern the adsorption layer thickness. 展开更多
关键词 triblock copolymers surface adsorption Monte Carlo simulation lattice model
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Morphologies of Core-Shell-Cylinder-Forming ABC Star Triblock Copolymers in Nanopores 被引量:1
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作者 Wen-bo Jiang Wen-chang Lang +1 位作者 Shi-ben Li Xiang-hong Wang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第3期337-342,共6页
The self-assembly behavior of ABC star triblock copolymers can lead to a large number of nanostructures. Indeed, many new and interesting structures have already been discovered and proven to be hotspot in soft matter... The self-assembly behavior of ABC star triblock copolymers can lead to a large number of nanostructures. Indeed, many new and interesting structures have already been discovered and proven to be hotspot in soft matter physics research. In this work, we introduce different phase diagrams of core-shell-cylinder-forming ABC star triblock copolymers under different conditions, including in-bulk and pore geometries with different sizes. The relation between the pore size geometries and their corresponding structures are also revealed. The different properties of the surface potential field that significantly affect the self-assembly process of ABC star triblock copolymers are investigated as well. 展开更多
关键词 Nanopore ABC star triblock copolymer Core-shell-cylinder-forming
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STUDIES ON MICELLE BEHAVIORS OF STYRENE-BUTADIENE-STYRENE (SBS) TRIBLOCK COPOLYMERS IN METHYL ETHYL KETONE (MEK) BY POSITRON ANNIHILATION TECHNIQUE
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作者 杨荣杰 叶美玲 +1 位作者 施良和 王蕴玉 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1992年第1期55-60,共6页
Positron annihilation technique was used to study the micelle behaviors of two SBS triblock copolymers in MEK solvent at different temperatures. Annihilation lifetime τ_3 of ortho-positronium (o-Ps) exhibited an obvi... Positron annihilation technique was used to study the micelle behaviors of two SBS triblock copolymers in MEK solvent at different temperatures. Annihilation lifetime τ_3 of ortho-positronium (o-Ps) exhibited an obvious transition from shorter lifetime to longer lifetime with temperature. It was attributed to the change of micelle behavior of SBS copolymer molecules in the solution. Experimental results of sedimentation velocity of ultracentrifuge were also reported. 展开更多
关键词 SBS triblock copolymer Micelle solution Positron annihilation
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An Overview of the Synthesis and Gene Transfer Properties of Triblock Copolymers Poly(2-Methyl-2-Oxazoline-b-Tetrahydrofurane-b-2-Methyl-2-Oxazoline)
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作者 Bazoly Rasolonjatovo Bruno Pitard +1 位作者 Philippe Guégan Hervé Cheradame 《Journal of Biomaterials and Nanobiotechnology》 2014年第2期53-65,共13页
The synthesis of poly(2-methyl-2-oxazoline-b-tetrahydrofurane-b-2-methyl-2-oxazoline) triblock copolymer of low molar mass has been carried out. Characterization of the purified polymer by 1H and 13C NMR spectroscopie... The synthesis of poly(2-methyl-2-oxazoline-b-tetrahydrofurane-b-2-methyl-2-oxazoline) triblock copolymer of low molar mass has been carried out. Characterization of the purified polymer by 1H and 13C NMR spectroscopies is described. These block copolymers did not give DNA containing polyplexes. The in vivo transfection properties were investigated by injection of tibialis muscles and intratracheal administration of female Swiss mice. These triblock copolymers with a molar ratio [2-methyl-2-oxazoline units]/[tetrahydrofurane units] in the 3 - 5 range gave a higher transfection efficiency than that of Lutrol or of PE6400 which are the gold standards of this transfection technique. Hydrolysis increased the performances of muscle transfection, showing the beneficial effect of the presence of positive charges, but was clearly detrimental to the transfection efficiency of pulmonary epithelium. 展开更多
关键词 triblock copolymer Cell Transfection Vector Gene Therapy Neutral Amphiphilic Block copolymers
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Phase Behavior of Sphere-Forming Triblock Copolymers in Films
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作者 Hong-Ge Tan Qing-Gong Song +1 位作者 Xin-Huan Yang Ya-Jing Deng 《Open Journal of Applied Sciences》 2012年第3期163-167,共5页
The self-assembly of sphere-forming triblock copolymers confined between two thin homogeneous surfaces is investigated based on mean-field dynamic density functional theory. The morphologies deviating from the bulk sp... The self-assembly of sphere-forming triblock copolymers confined between two thin homogeneous surfaces is investigated based on mean-field dynamic density functional theory. The morphologies deviating from the bulk sphere-forming phase are revealed, including cylinders oriented perpendicular to the surface, cylinders oriented parallel to the surface, perforated lamellae and lamellae by varying film thickness and surface field strength. The phase diagram of surface reconstruction is also constructed. By comparing the present phase diagram with the other relevant phase diagram for the cylinder-forming triblock copolymer film, the difference between the sphere-forming and the cylinder-forming triblock copolymer thin film is discussed. 展开更多
关键词 triblock copolymER MEAN-FIELD Dynamic Density Functional Theory THIN Film
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Electrochemical and Thermal Properties of Polymer Electrolytes Based on the Random and Triblock Copolymers of Poly(Ethylene Oxide) with Poly(Propylene Oxide)
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作者 Masashi Matsumoto Takahiro Uno +1 位作者 Masataka Kubo Takahito Itoh 《材料科学与工程(中英文A版)》 2011年第5X期607-615,共9页
关键词 聚合物电解质 三嵌段共聚物 电化学稳定性 热性能 环氧乙烷 环氧丙烷 随机和 离子电导率
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SELF ASSEMBLY OF ABC TRIBLOCK COPOLYMER THIN FILMS ON A BRUSH-COATED SUBSTRATE 被引量:1
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作者 汪蓉 薛奇 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第4期583-592,共10页
Self assemblies of ABC triblock copolymer thin films on a densely brush-coated substrate were investigated by using the self-consistent field theory.The middle block B and the coated polymer form one phase and the alt... Self assemblies of ABC triblock copolymer thin films on a densely brush-coated substrate were investigated by using the self-consistent field theory.The middle block B and the coated polymer form one phase and the alternating phase A and phase C occur when the film is very thin either for the neutral or selective hard surface(which is opposite to the brushcoated substrate).The lamellar phase is stable on the hard surface when it is neutral and interestingly,the short block tends to stay on this hard surface... 展开更多
关键词 Functional self-assembly Thin film Simulation Self-consistent field theory ABC triblock copolymer
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Effect of Poly(ε-caprolactone-b-tetrahydrofuran)Triblock Copolymer Concentration on Morphological,Thermal and Mechanical Properties of Immiscible PLA/PCL Blends 被引量:1
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作者 Paula do Patrocínio Dias Marcelo Aparecido Chinelatto 《Journal of Renewable Materials》 SCIE 2019年第2期129-138,共10页
In this study a low molecular weight triblock copolymer derived fromε-caprolactone and tetrahydrofuran was used as a non-reactive compatibilizer of immiscible PLA/PCL blends.Ternary blends with 0,1.5 wt%,3 wt%and 5 w... In this study a low molecular weight triblock copolymer derived fromε-caprolactone and tetrahydrofuran was used as a non-reactive compatibilizer of immiscible PLA/PCL blends.Ternary blends with 0,1.5 wt%,3 wt%and 5 wt% copolymer and about 75 wt%PLA were prepared by single screw extrusion and characterized by scanning electron microscopy(SEM),differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),tensile and Izod impact testing.SEM micrographs showed that the size of the dispersed PCL domains was practically constant regardless of copolymer concentration.This result can be explained by the low shear rate employed during processing step and a decrease of PCL viscosity by presence of the triblock copolymer.However,when the copolymer concentration increased,strain at break of PLA/PCL blends also increased.PLA/PCL blend with 0 wt% copolymer presented 2%strain at break,whereas PLA/PCL blend with 5 wt%copolymer exhibited 90%. 展开更多
关键词 BLENDS non-reactive compatibilization poly(lactic acid) poly(ε-caprolactone) triblock copolymer
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Self-assembly of block copolymers grafted onto a flat substrate:Recent progress in theory and simulations
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作者 王铮 李宝会 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第1期270-281,共12页
Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the... Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applica- tions; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB dibloek eopolymers, junction p0int-grafted AB diblock copolymers (i.e., Y-shaped brushes), and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress. 展开更多
关键词 grafted AB diblock copolymers grafted ABA triblock copolymers SELF-ASSEMBLY block copoly-mer brushes
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Electrorheological Properties of Suspensions of PAn-PEO-PAn Triblock Copolymer Particles
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作者 马会茹 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2005年第4期43-45,共3页
The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α,ω-bis(p-aminophenyl)poly(ethylene glycol)and characterized by FT-IR and... The PAn-PEO-PAn triblock copolymer with the PEG chain length of 400 was synthesized by chemical oxidation copolymerization of aniline and α,ω-bis(p-aminophenyl)poly(ethylene glycol)and characterized by FT-IR and TEM.The experimental results show that the copolymer particles are of μtypical core-shell structure after the self-assembly process in water.Its conductivity is much lower than that of the pure PAn.The suspension containing 20 vol% PAn-PEO-PAn tiblock copolymer in silicone oil exhibits.a typical electrorheological (ER) effect in DC electric field.while it shows a lower leakage current density than that of the pure PAn-based ER fluids.Therefore,the PEO shell hinders the electric hop among PANI chains and decreases the current density of ER fluids in an external electric field.at the same time the interface polarity improves the ER effects. 展开更多
关键词 PAn-PEO-PAn triblock copolymer core-shell particles ER properties
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Thermal Stability Improvement and Structural Change of Oil Gels Formed by Styrene-Butadiene-Styrene Triblock Copolymer Induced by Adding Poly(phenylene ether)
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作者 Kouichi Kato Yuki Tsukamoto +2 位作者 Eri Hirai Yasuhiro Matsuda Shigeru Tasaka 《Open Journal of Organic Polymer Materials》 2014年第4期65-73,共9页
The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg)... The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg). In naphthenic oil which is a good solvent for the butadiene blocks, but a non-solvent for the styrene blocks and PPE, PPE was selectively included into styrene blocks in SBS, and induced the increase of the Tg of these blocks. The melting temperature determined by viscoelastic measurements and softening temperature of the gels were elevated by adding PPE, while no significant change was detected by adding polystyrene. The gel became opaque by adding PPE, and partially separated phases were observed by field emission scanning electron microscopy (FE-SEM). The dependence of the viscoelastic behavior on the PPE concentration can be explained by the structural change observed by FE-SEM. 展开更多
关键词 Styrene-Butadiene-Styrene triblock copolymer Poly(phenylene ether) (PPE) OIL Gel Naphthenic OIL
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MONTE CARLO SIMULATION OF TRIBLOCK COPOLYMER/HOMOPOLYMER BLEND FILMS
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作者 HUANG Yongmin XIAO Xingqing +1 位作者 LIU Honglai HU Ying 《Chinese Journal of Reactive Polymers》 2006年第2期167-173,共7页
The morphologies of triblock copolymer/homopolymer blend films, ABA/A and ABAIB, confined between two neutral hard walls were studied via Monte Carlo (MC) simulation on a simple .cubic lattice. The effects of φh (... The morphologies of triblock copolymer/homopolymer blend films, ABA/A and ABAIB, confined between two neutral hard walls were studied via Monte Carlo (MC) simulation on a simple .cubic lattice. The effects of φh (the volume fraction of homopolymer) and Md/Mb (the molecular weight of homopolymer in relation to that of the corresponding blocks in the copolymer) on the morphologies were investigated in detail. 展开更多
关键词 MC simulation triblock copolymer/homopolymer blend film MORPHOLOGY
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三嵌段共聚物临界胶束浓度与分子横截面积测定
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作者 黄斐斐 田福平 +2 位作者 戴岳 张艳娟 贺民 《实验室科学》 2024年第2期43-46,共4页
采用双毛细管最大泡压法装置测定了25℃条件下不同浓度非离子表面活性剂聚乙二醇-聚丙二醇-聚乙二醇三嵌段共聚物(PEG-PPG-PEG;Pluronic L-64)对溶液表面张力的影响。采用Origin软件对数据进行处理分析,计算得到其临界胶束浓度(CMC)。... 采用双毛细管最大泡压法装置测定了25℃条件下不同浓度非离子表面活性剂聚乙二醇-聚丙二醇-聚乙二醇三嵌段共聚物(PEG-PPG-PEG;Pluronic L-64)对溶液表面张力的影响。采用Origin软件对数据进行处理分析,计算得到其临界胶束浓度(CMC)。基于吉布斯(Gibbs)与朗格缪尔(Langmuir)吸附等温式,对溶液表面张力与浓度关系进行一步非线性拟合,计算获得吸附分子的横截面积。该实验扩展了最大泡压法测定表面张力的应用,提高了学生分析处理实验数据的能力。 展开更多
关键词 最大泡压法 聚乙二醇-聚丙二醇-聚乙二醇三嵌段共聚物 临界胶束浓度 分子横截面积
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Enhanced stability of nitrogen-doped carbon-supported palladium catalyst for oxidative carbonylation of phenol
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作者 Xiaojing Liu Ruohan Zhao +4 位作者 Hao Zhao Zhimiao Wang Fang Li Wei Xue Yanji Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期19-28,共10页
Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticle... Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and industry.Herein,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen source.The Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 addition.The hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd NPs.This process helped to improve metal dispersion.The increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF catalyst.Furthermore,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction process.This work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts. 展开更多
关键词 Supported Pd catalyst N-doped carbon Amphiphilic triblock copolymer Pyridinic nitrogen STABILITY
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活性三嵌段共聚物的凝胶化转变
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作者 石子璇 金燕 +3 位作者 金奕扬 田文得 张天辉 陈康 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第17期97-105,共9页
活性物质的自推进特征引发了许多非平衡自组织现象,而聚合物链的构象自由度可以使链产生独特的平衡自组装行为,这激发了活性物质与聚合物物理的交叉研究.本文通过分子动力学模拟,研究了自驱动活性对ABA型三嵌段共聚物凝胶化转变的调控.... 活性物质的自推进特征引发了许多非平衡自组织现象,而聚合物链的构象自由度可以使链产生独特的平衡自组装行为,这激发了活性物质与聚合物物理的交叉研究.本文通过分子动力学模拟,研究了自驱动活性对ABA型三嵌段共聚物凝胶化转变的调控.研究结果表明活性嵌段共聚物凝胶的塌缩源于自驱动活性引起的网络链运动,活性越大则凝胶网络越容易产生大直径空洞.在凝胶网络的拓扑缺陷方面,当A嵌段之间吸引强度较大时,环链比例随活性力增强而增大,吸引强度较小时情况则相反.交联点的分支数随活性的变化除了受到吸引强度的影响,还与链刚性有关.在动力学方面,活性聚合物的定向运动会引发稳定聚合物凝胶整体的反常扩散.本文的研究有助于增进对活性聚合物集体行为的认识,为高分子活性材料的设计和应用提供了新的思路. 展开更多
关键词 活性物质 ABA 三嵌段共聚物 非平衡系统 聚合物凝胶
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层状ABC星型三嵌段共聚物和纳米颗粒的自组装
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作者 晏妙 张迎彤 王向红 《温州大学学报(自然科学版)》 2024年第2期19-26,共8页
采用耗散粒子动力学模拟方法研究了层状ABC星型三嵌段共聚物和纳米颗粒的协同自组装.主要考虑了不同密度下纳米颗粒的聚集行为及其对层状结构的影响.当纳米颗粒密度较低时,纳米颗粒呈囊泡状聚集;当纳米颗粒密度较高时,纳米颗粒呈柱状聚... 采用耗散粒子动力学模拟方法研究了层状ABC星型三嵌段共聚物和纳米颗粒的协同自组装.主要考虑了不同密度下纳米颗粒的聚集行为及其对层状结构的影响.当纳米颗粒密度较低时,纳米颗粒呈囊泡状聚集;当纳米颗粒密度较高时,纳米颗粒呈柱状聚集.通过分析体系能量和共聚物链的回转半径研究了该动力学过程;通过界面张力的计算,对体系中微结构的力学性能进行了探索.这些发现不仅有助于人们了解复杂的嵌段共聚物,也可以为探索嵌段共聚物和纳米颗粒的微结构提供思路,对研究嵌段共聚物纳米复合材料的潜在应用提供帮助. 展开更多
关键词 耗散粒子动力学 ABC星型三嵌段共聚物 纳米颗粒 自组装
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Ir和IrPd催化剂的合成及结构调控对其甲醇氧化性能的影响
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作者 周新文 沈晓宇 +5 位作者 付策 王攀 严烙意 程征 田贵贤 张荣华 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第2期412-420,共9页
以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO_(20)-PPO_(70)-PEO_(20))为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法... 以三嵌段共聚物P123(聚环氧乙烷-聚环氧丙烷-聚环氧乙烷,PEO_(20)-PPO_(70)-PEO_(20))为还原剂和保护剂,比较了水热法和溶剂热法对纯Ir和IrPd合金催化剂合成及其电催化氧化甲醇(MOR)性能的影响。对于纯Ir催化剂,在相同条件下,溶剂热法能更好地促进Ir前驱体的还原。对于IrPd合金催化剂,溶剂热法可制得表面富含Ir但MOR活性较低的核壳结构产物(IrPd-S)。水热反应得到的不同原子比(IrPd、Ir2Pd、IrPd_(2))的产物粒径更小,元素分布更均匀。其中比例为1:1的IrPd(IrPd-H)催化剂的MOR电催化活性最高。上述结果表明,通过调节溶剂类型以及P123的结构诱导作用,可以有效地调节纯Ir和IrPd合金催化剂的结构、表面组成和电催化活性。 展开更多
关键词 结构调控 水热合成 钯铱合金 三嵌段共聚物 甲醇氧化
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