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PREPARATION OF CARBON NANOFIBERS BY polymer blend TECHNIQUE

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Chinese Journal of Reactive polymers 2007年第Z1期 108-111页

作者： LING Fen YANG Pengfei PAN Wei YANG Shenglin LI Guang College of Material Science and Engineering, Donghua University, Shanghai 200051, China.

The polymer blend technique is a novel method to produced carbon nanofibers. In this paper, we have prepared fine carbon fibers and porous carbon materials by this technique, and we will discuss the experiment results... 详细信息

关键词： Carbon nanofibers polymer blend Wet-spinning Compatibility Morphology.

Formation of biomimetic hierarchical nanostructure in homopolymers and block copolymer ternary blend particles

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Particuology 2022年第5期20卷 98-109页

作者： Shu Kikuchi Ryoka Shoji Shinji Kanehashi Guanghui Ma Kenji Ogino Graduate School of Bio-Applications and Systems Engineering Tokyo University of Agriculture and Technology2-24-16 NakachoKoganei-shiTokyo 184-8588Japan Institute of Global Innovation Research Tokyo University of Agriculture and Technology2-24-16 NakachoKoganei-shiTokyo 184-8588Japan State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100080China

In order to mimic hierarchical nanostructures in nature,particles of polymer blends consisting of poly(4-butyltriphenylamine)(PBTPA),poly(methyl methacrylate)(PMMA)and PBTPA-block-PMMA were fabricated by a solvent evaporation method.Effects of the molecular weight and the chemical composition of PBTPA-b-PMMA,molecular weights of homopolymers,and the composition of the blend on the morphology were investigated.The polymer blend particle consisting of PBTPA and PMMA homopolymers exhibited thermodynamically favored core-shell structure,in which more hydrophilic PMMA-shell surrounded PBTPA-core.The addition of 10 wt%of PBTPA-b-PMMA caused the morphological transition from core-shell toJanus or inversed core-shell,in which PBTPA-shell surrounded PMMA-core,depending on the molecular weight of PBTPA segment in PBTPA-b-PMMA.When the molecular weight of PMMA segment was higher than that of PMMA homopolymer,watermelon-like particles in which small PBTPA domain less than 80 nm dispersed in the PMMA domain surrounded by PBTPA shell were observed.As the ratio of PBTPA-b-PMMA increased,the interface of the macrophase separation became obscure.At 50 wt%of the PBTPA-b-PMMA,only microphase separation was observed.The measurement of interfacial tension by pendant drop method demonstrated that PBTPA-b-PMMA lower the interfacial tension between PBTPA and the aqueous phase to the value similar to that of PMMA with the aqueous phase.

关键词： Microsphere Hierarchical structure polymer blend Block copolymer Solvent evaporation Phase separation

UNIQUE EVOLUTION OF SPATIAL AND DYNAMIC HETEROGENEITIES ON THE GLASS TRANSITION BEHAVIOR OF PVPh/PEO blendS

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Chinese Journal of polymer Science 2012年第6期30卷 900-915页

作者：孙平川 Key Laboratory of Functional polymer Materials Ministry of EducationCollege of ChemistryNankai University

Glass transition behavior of hydrogen bonded polymer blends of poly（vinyl phenol）（PVPh） and poly（ethylene oxide）（PEO） is systematically investigated using normal differential scanning calorimetry （DSC） and recently developed multifrequency temperature-modulated DSC （TOPEM）, in combination with Fourier transform infrared spectroscopy （FTIR） and nuclear magnetic resonance （NMR） techniques, focusing on the effect of the PEO molecular weight on the spatial and dynamic heterogeneity. It is found, for the first time, that both the glass transition temperature （Tg） and activity energy （Ea） of the blends strongly depend on PEO molecular weight, and a common turning point, which separates the rapid and slow increasing regions, can be found. The interchain hydrogen bonding interactions, both determined by FTIR measurements and obtained from the Kwei equation, decrease with increasing PEO molecular weight, indicating a decrease of the componential miscibility. A series of parameters related to the microscopic spatial and dynamic heterogeneity, such as the activity energy, fragility, nonexponential factor and the size of cooperatively rearranging regions, are calculated from frequency dependency complex heat capacity measured using TOPEM. It is found that each of these parameters monotonically changes with increasing the PEO molecular weight during the glass transition process, demonstrating that hydrogen bonding interaction is the key factor in controlling the spatial and dynamic heterogeneity, thus the glass transition. NMR relaxation results reveal the existence of obvious phase separation large than 5 nm, implying that the cooperatively rearranging regions should be closely related to the interphase region between the two components. The above obtained origin and evolution of spatial and dynamic heterogeneity provide a new insight into the glass transition behavior of polymer blends.

关键词： Glass transition polymer blend DSC FTIR Solid-state NMR.

blend MEMBRANES FOR DIRECT METHANOL AND PROTON EXCHANGE MEMBRANE FUEL CELLS

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Chinese Journal of polymer Science 2012年第4期30卷 548-560页

作者： Perumal Bhavani Dharmalingam Sangeetha Department of Chemistry Anna UniversityChennai 25India

Sulphonated polystyrene ethylene butylene polystyrene （SPSEBS） prepared with 35% sulphonation was found to be highly elastic and enlarged up to 300%-400% of its initial length. It absorbed over 110% of water by weight. A major drawback of this membrane is its poor mechanical properties which are not adequate for use as polymer electrolytes in fuel cells. To overcome this, SPSEBS was blended with poly（vinylidene fluoride）（PVDF）, a hydrophobic polymer. The blend membranes showed better mechanical properties than the base polymer. The effect of PVDF content on water uptake, ion exchange capacity and proton conductivity of the blend membranes was investigated. This paper presents the results of recent studies applied to develop an optimized in-house membrane electrode assembly （MEA） preparation technique combining catalyst ink spraying and assembly hot pressing. Easy steps were chosen in this preparation technique in order to simplify the method, aiming at cost reduction. The open circuit voltage for the cell with SPSEBS is 0.980 V which is higher compared to that of the cell with Nation 117 （0.790 V）. From this study, it is concluded that a polymer electrolyte membrane suitable for proton exchange membrane fuel cell （PEMFC） and direct methanol fuel cell （DMFC） application can be obtained by blending SPSEBS and PVDF in appropriate proportions. The methanol permeability and selectivity showed a strong influence on DMFC performance.

关键词： Fuel cell Impedance polymer blend Proton conductivity.

polymeric artificial solid/electrolyte interphases for Li-ion batteries

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Progress in Natural Science:Materials International 2015年第6期25卷 563-571页

作者： Nae-Lih Wu Yu-Ting Weng Fu-Sheng Li Nai-Hsuan Yang Chin-Lung Kuo Dong-Sheng Li Deprtment of Chemical Engineering National Taiwan University Department of Materials Science and Engineering National Taiwan University

During the operation of Li-ion batteries(LIBs),solvent and electrolyte decomposition takes place at the electrode surface to form a so-called solid-electrode interphase(SEI) passivating-layer.The physical structure and chemical composition of the SEI exert profound effects on various aspects of the electrode performance of the batteries.A new concept of forming polymeric artificial SEIs(A-SEIs) based on rational design of multifunctional polymer-blend coating to achieve favorable electrode/A-SEI/electrolyte interfacial properties is described.Three examples using binary and ternary polymer blends to form mechanically robust and highly Li-ion permeable surface coatings with selected functionalities in the cases of graphite and silicon–graphite composite electrodes have demonstrated greatly enhanced capacity,rate and cycle performance.Given the rich chemistry available from polymer blends,this surface preconditioning approach holds great promise for improving the performance of various negative electrodes to meet the requirements for advanced LIBs.

关键词： Li ion battery Solid electrolyte interphase Surface modification polymer blend

Fabrication of Highly Anisotropic and Interconnected Porous Scaffolds to Promote Preosteoblast Proliferation for Bone Tissue Engineering

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Chinese Journal of polymer Science 2021年第9期39卷 1191-1199页

作者： Ya-Hui Liu Wei Liu Zi-Li Zheng Xin Wei Nouman Ali Shah Hao Lin Bai-Song Zhao Shi-Shu Huang Jia-Zhuang Xu Zhong-Ming Li College of polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China Department of Anesthesiology Guangzhou Women and Children's Medical CenterGuangzhou 510623China Department of Orthopaedic Surgery West China HospitalSichuan UniversityChengdu 610065China

Mimicking the complex structure of natural bone remains a challenge for bone tissue scaffolds.In this study,a novel processing strategy was developed to prepare the bone-like scaffolds that are featured by highly oriented and fully interconnected pores.This type of biomimetic scaffolds was evolved from solid phase stretching of immiscible polycaprolactone(PCL)/poly(ethylene oxide)(PEO)blends with cocontinuous structure and the pore morphology was inherited from selective extraction of water soluble PEO phase.The pore anisotropy was readily tuned by varying the stretching strain without loss of interconnectivity.Significant promotion in preosteoblast proliferation,alkaline phosphatase activity and osteogenic gene expression was observed in the oriented porous scaffolds compared to the isotropic porous counterpart.The oriented architecture provided a topographical cue for aligned growth of preosteoblasts,which activated the Wnt/β-catenin signaling pathway.The proposed strategy enriches the toolbox for the scaffold design and fabrication for bone tissue engineering.

关键词： Porous scaffold Pore anisotropy polymer blend Co-continuous structure Tissue engineering

Polyaniline-poly(vinylidene fluoride) blend microfiltration membrane and its spontaneous gold recovery application

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Science China Chemistry 2018年第1期61卷 118-126页

作者： Gang Liu Tangliu Yan Yuanzhao Wu Xiaohui Yi Bin Chen Run-Wei Li CAS Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China Zhejiang Province Key Laboratory of Magnetic Materials and Applied Technology Ningbo Institute of Materials Technology and Engineering. Chinese Academy of Sciences Ningbo 315201 China University of Chinese Academy of Sciences Beijing 100049 China

Structural regular polyaniline was synthesized via a modified-chemical oxidative polymerization reaction. Highly hydrophilic polyaniline(PANi) and polyaniline-poly(vinylidene fluoride) blend(PANi-PVDF) membranes were prepared by solution casting and phase inversion techniques. Both of the mechanical and filtration properties of the membranes depend on the polymer composition and doping level of the blends. The elasticity of the membrane is greatly improved upon introducing poly(vinylidene fluoride) into the blend. The water permeability of the blend membranes is further enhanced when the membranes are doped with hydrochloric acid. The PANi-PVDF blend membranes are capable of recovering metallic gold from the acid/halide leaching streams spontaneous and sustainably, and are promising candidates for wastewater treatments in electronic industries.

关键词： polyaniline poly(vinylidene fluoride) polymer blend microfiltration membrane gold recovery

Preparation of Polypropylene/Poly(styrene-co-(butyl methacrylate)) Nanoblends by Diffusion and Subsequent Copolymerization of Monomers in Isotactic Polypropylene Pellets

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Chinese Journal of polymer Science 2015年第10期33卷 1380-1388页

作者： Hai-yue Qiu Fang Chen 郭朝霞于建 Key Laboratory of Advanced Materials(MOE) Department of Chemical Engineering Tsinghua University

The diffusion and subsequent copolymerization of styrene （St）/butyl methacrylate （BMA） mixed monomers in iPP pellets to prepare copolymer nanoblends were investigated. The diffusion step was carded out at 90 ℃ for 2 h in water, and the copolymerization was initiated by the addition of BPO with the aid of a small amount of St. The diametrical distributions of both St and BMA units and their ratio St/BMA were investigated by micro FTIR. Both St and BMA can diffuse into the centres of iPP pellets. The diametrical distribution of St/BMA ratio is constant in all the copolymer blends. The copolymer composition depends on the comonomer feed ratio. The molecular weights of the copolymers were measured by GPC after extraction with tetrahydrofuran. The phase morphology of the copolymer blends was investigated by FESEM, showing the average particle sizes of less than 100 nm. DSC measurements show that the diffusion and subsequent copolymerization of St/BMA monomers only occur in the amorphous regions of iPP pellets.

关键词： Polypropylene polymer blend Diffusion Copolymerization

Comparison of the Free Volume of LiCl-Added SPPO Membrane and SPPO-PES blend Membrane by Positron Annihilation Method

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Plasma Science and Technology 2007年第5期9卷 575-577页

作者： Htwe Htwe YIN 黄环唐世彪马庆力 Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Center of Physical Experiment and Teaching School of ScienceUniversity of Science and Technology of ChinaHefei 230026China Electronics Department Electronic Engineering InstituteHefei 230038China

Positron annihilation lifetime spectroscopy （PALS） is a powerful technique for the study of free volume in polymers. The lifetime of ortho-positronium （o-Ps）, a bound state of an electron and a positron, can be used to assess the pore size, while the intensity can be used to characterize the number of pores. Based on the values of the long-lived o-Ps components in the lifetime spectra, the radii and fractional free volumes of sulfonated poly （2,6-dimethyl-1,4- phenyleneoxide）（SPPO） membranes with added LiCl and SPPO-PES （Polyethersulfone） blend were compared. Free volume radii in both kinds of membranes are discussed.

关键词： positron annihilation free volume pore size SPPO polymer blend