检索结果-南通市图书馆

Adsorption properties of the double-imprinted electrospun crosslinked chitosan nanofibers

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2019年第3期30卷 762-766页

作者： Yan Li Mengqi Li Jie Zhang Xiaoyan Xu School of Materials Science and Engineering Tongji University Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic Chemistry Chinese Academy of Sciences

The adsorption properties of the Pb(Ⅱ)-Cd(Ⅱ) double-imprinted electrospun crosslinked chitosan nanofibers(Pd/Cd-DIECCNs) prepared by electropspinning and imprinting process for the removal of Pb(Ⅱ) and Cd(Ⅱ) from aqueous solutions were investigated. The prepared nanofibers were characterized by scanning electron microscope(SEM) analysis. Under the optimum experimental conditions, the minimum fiber average diameter was obtained 110 nm. Then the adsorption experiments were carried out to study the effect of different adsorption parameters, such as pH, the ratio between Pb(Ⅱ) and Cd(Ⅱ)in the mixed solutions, contact time, the Pd/Cd-DIECCNs dose and temperature in a batch system. The Extended Langmuir model was applied to describe the equilibrium data of Pb(Ⅱ) and Cd(Ⅱ). The maximum adsorption capacities of the Pd/Cd-DIECCNs arrived at 567 mg/g for Pb(Ⅱ) and 341 mg/g for Cd(Ⅱ), respectively.

关键词： Chitosan Double imprinted crosslinked Electrospun Adsorption

Synthesis and characterization of thermally crosslinked polyimide with second-order nonlinear optical chromophore

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1998年第4期41卷 395-402页

作者：孟继本麻洪沈玉全陈萍李晓陆李金亮王永梅 Department of Chemistry Nankai University Tianjin China Institute of Photographic Chemistry Chinese Academy of Sciences Beijing China

Synthesis of three novel crosslinked polyimides with push pull azobenzene group has been developed. 4 Nitro 4′ [N,N bis(2 aminoethyl)]aminoazobenzene was first prepared, then poly(amic acid) prepolymer, one crosslinkable component, was obtained by aminolysis of alternating styrene maleic anhydride copolymer, alternating thiophene maleic anhydride copolymer or alternating benzofuran maleic anhydride copolymer with it, and at last the crosslinked second order nonlinear optical polyimide was synthesized by crosslinking and imidizing poly(amic acid) prepolymer with corresponding alternating copolymer. The crosslinking and imidizing processes were studied by IR and UV Vis spectra. The chromophore density in one of the crosslinkable components, poly(amic acid) prepolymer, and the thermal stability of crosslinked polyimide thin film were measured by UV Vis spectra.

关键词： crosslinked polyimide azobenzene alternating copolymer second order nonlinear optical material.

PREPARATION OF MONODISPERSE crosslinked POLYMER MICROSPHERES HAVING CHLOROMETHYL GROUP BY DISTILLATIONPRECIPITATION POLYMERIZATION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2005年第2期23卷 197-202页

作者： Shu-FengLi Xin-LinYang Wen-QiangHuang StateKeyLaboratoryofFunctionalPolymerMaterialsforAdsorptionandSeparation InstituteofPolymerChemistryNankaiUniversityTianjin300071China

Monodisperse crosslinked poly(chloromethylstyrene-co-divinylbenzene)(poly(CMSt-co-DVB))microsphereswere prepared by distillation-precipitation copolymerization of chloromethylstyrene(CMSt)and divinylbenzene(DVB)inneat acetonitrile.The polymer particles had clean surfaces due to the absence of any added stabilizer.The size of the particlesranges from 2.59 μm to 3.19 μm and with mono-dispersity around 1.002-1.014.The effects of monomer feed incopolymerization on the microsphere formation were described.The polymer microspheres were characterized by SEM andchlorinity elemental analysis.

关键词： Chloromethylstyrene Divinylbenzene Distillation-precipitation polymerization crosslinked Monodisperse Polymer microspheres Chlorinity.

POLYETHYLENE crosslinked WITH ULTRAVIOLET LIGHT

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1991年第2期36卷 127-129页

作者：徐文英严庆 BENGT RNBY Department of Materials Science and Engineering University of Science and Technology of China Hefei 230026 PRC Department of Polymer Technology Royal Institute of Technology Sweden.

It was first proposed by Oster in 1956 that polyethylene could be crosslinked with ultraviolet fight in the presence of some photosensitizers. But the photocrossfinking method was not used in industry for a long period because the penetration of the light is limited. The recent work done by Rnby et al. is outstanding in the improvement on this method, and it is competitive to the high-energy irradiation method and the thermalchemistry method. Therefore, the photocrosslinking has a promising prospect in application now. This note is a brief introduction to the results about the theoretical analysis and

关键词： photocrosslinking crosslinked polyethylene photostabilization.

A New Method for Preparation of Anion Exchange Resins Based on crosslinked Polvstvrene

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 1997年第2期3卷 76-79页

作者：许辉 Institute of Chemistry Academia Sinica Beijing 100080 P. R. China

This paper presents a new method for preparing anion exchange resins based on crosslinked polystyrene which consists in the acylation of crosslinked polystyrene by FriedelCrafts reaction followed by reductive amination. Aminated resins are quaternized to formcorresponding strong base anion exchange resins. The method avoids the use of carcinogenic chloromethyl methyl ether which is widely used in the preparation of commercial anion exchange resins.

关键词： Anion exchange resins crosslinked polystyrene Preparation

Photophysical Study of Pyrene-labelled St/DVB Copolymers

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1994年第5期37卷 513-521页

作者：何炳林王国昌李新松陈柳生杜金环 Institute of Polymer Chemistry Nankai University Tianjin 300071 PRC Institute of Chemistry Academia Sinica Beijing 100080 PRC

The photophysical properties of a series of pyrene-labelled styrene/divinyl benzene (St/ DVB) copolymers have been studied for the first time by steady-state fluorescence spectra. The results indicate that when pyrenyl content (mol%) in the copolymer is lower than 0. 006% , the fluorescence spectra only show the pyrenyl monomer emission, while the 0-0 transition band is much suppressed and the vibronic structure is partially lost. However, in the fluorescence spectra of the copolymers with pyrenyl content higher than 0.3%, there appear some new emission bands at ca 420 nm, 440 nm and 475 nm. These results are explained in terms of the formation of ground-state and excited-state aggregates, which reveals the heterogeneity of the crosslinked networks.

关键词： pyrene photophyslcs ground-state aggregate crosslinked structure.

Studies on the heterogeneity of St/DVB copolymers by phenyl aggregate fluorescence

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1995年第9期38卷 1046-1054页

作者：王国昌叶彦春高焕何炳林栗凤珍高传喜 Institute of Polymer Chemistry Nankai UniversityTianjin 300071China Experimental Centre Tianjin Normal UniversityTianjin 300068China

A new method for characterizing St/DVB copolymer heterogeneity by phenyl aggregatefluorescence has been developed and used to study the effects of crosslinking degree,crosslinker and diluent onthe heterogeneity of the copolyruer gels.The results show that St/m-DVB copolymer gel is more homogeneousin structure than St/p-DVB copolymer gel,whereas increasing crosslinking degree and the proportion of goodsolvent in diluent lead to an increase of gel heterogeneity.These results provide structural evidence which mayserve as a bridge between St/DVB crosslinking reaction and the copolymer properties.

关键词： phenyl aggregate fluorescence crosslinked copolymers gel heterogeneity.

Approach for Reliability Evaluation of Cross-Linked Polyethylene Under Combined Thermal and Vibration Stresses

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2018年第6期23卷 758-763页

作者：刘骥张明泽陈昕齐朋帅 Key Laboratory of Engineering Dielectrics and Its Application Ministry of Education Harbin University of Science and Technology Heilongjiang Electric Power Research Institute

Based on Wiener process model, a new approach for reliability evaluation of cross-linked polyethylene(XLPE) is proposed to improve the lifetime evaluation reliability of XLPE under multi-stressing conditions and study the failure probability distribution. In this paper, two accelerated aging tests are carried out under combined thermal and vibration conditions. The volume resistance degradation data of XLPE samples are tested with a24 h interval under the accelerated stressing conditions at(130℃, 12 m/s^2) and(150℃, 8.5 m/s^2), respectively.Nonlinear degradation data obtained from the experiment are transformed to linear intermediate-variable values using time scaling function, and then linearized degradation data are calculated and evaluated on the basis of linear Wiener process model. Considering traditional Arrhenius equation and inverse power criterion, parameters of the linear Wiener model are estimated according to the maximum likelihood function. The relationship curves on probability density and reliability are given, and the lifetime distribution of XLPE under different stressing conditions is also obtained for evaluating the reliability of XLPE insulation. Finally, the life expectancy of XLPE is 17.9 a under an allowance temperature of 90℃ and an actual vibration acceleration of 0.5 m/s^2. The approach and results in this paper may be used for reliability assessment of high-voltage multiple samples or apparatuses.

关键词： accelerated multifactor aging lifetime evaluation reliability distribution degradation test crosslinked polyethylene (XLPE)

crosslinked Polymer Injection Showing Notable Effectiveness in Shengli Oilfields

在线全文

学校读者我要写书评

暂无评论

China Oil & Gas 1994年第1期1卷 42-42页

作者： $$$$Zhao Shouzeng(Oil production Technology Research Institute, Shengli Petroleum Administration Bureau) Oil Production Technology Research Institute Shengli Petroleum Administration Bureau

After more than half a year of crosslinked polymer inection test, oil production increased notably in western district No.7 of Gudong Oil Production Plant, Shengli Oilfields. In the test area, through the test daily fluid production increased from 397.9 tons to 434.6 tons and daily oil production increased from 79.6 to 101.3 tons, but comprehensive water cut dropped from 80.6% to 79.6%.

关键词： Polymer Injection Oilfields Shengli Notable Showing crosslinked Effectiveness