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Chinese Journal of polymer science 2001年第5期19卷 493-498页

作者： Chang-you Gao jian-jun Guan jia-cong shen department of polymer science and engineering zhejiang university hangzhou 310027, china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Two grafting methods, i.e. solution grafting and pre-adsorbing, are introduced to covalently immobilizehydrophilic polymers on segmented polyurethane (SPU) to modify its hydrophilicity and to improve its cell *** grafting results in higher degree of grafting and rougher surface morphology. Cell culture evaluation demonstratesthat the modified membranes thus obtained are disadvantageous to the endothelial cell (ECs) growth probably because thehydrophilic groups on the surface are over-crowded. However, pre-absorbing grafting generates lower degree of grafting,which is detected and confirmed by ATR-FTIR spectra and water conted angle. Scanning electron microscopic (SEM)measurement shows that the latter method produces a plane and smooth morphology, which is similar to the SPU controlsample controlled. When grafting with lower monomer concentration, ECs could grow on SPU-g-PHEA [poly(2-hydroxyethyl acrylate)], SPU-g-PAAm (polyacrylamide), SPU-g-PDMA [poly(2-(dimethylamino)ethyl methacrylate)] orquatemized SPU-g-PDMA surface with elongated cell shapes. Hence, the cell compatibility of SPU is improved and a usefulmethod to construct a cell compatible layer on the polymer surface has been developed.

关键词： segmented polyurethane cell compatibility surface grafting endothelial cell

A NOVEL RESISTIVE HUMIDITY SENSOR BASED ON SODIUM POLYSTYRENESULFONATE/TiO_2 NANOCOMPOSITES

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Chinese Journal of polymer science 2002年第3期20卷 237-241页

作者： Yang Li Mu-jie Yang Yong She department of polymer science and engineering zhejiang university, hangzhou 310027 china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2 nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis (< 4% RH) and quicker response (absorption: less than 2 s; desorption: less than 20 s) in comparison with sensor composed of NaPSS. The effect of concentration of NaPSS and TiO2 on humidity response of sensors was discussed.

关键词： humidity sensor nanocomposites TiO2 sodium polystyrenesulfonate

Lanthanum heterocyclic Schiff-base complex initiated ring-opening polymerization of ε-caprolactone

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Chinese Chemical Letters 2007年第9期18卷 1133-1136页

作者： Wen Lin Wei Lin Sun Zhi Quan shen department of polymer science and engineering,zhejiang university,hangzhou 310027,china department of polymer science and engineering Zhejiang University Hangzhou 310027 China

Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was *** study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.

关键词： Heterocyclic Schiff-base Rare earth complex ε-Caprolactone Ring-opening polymerization

RANDOM COpolymer OF PROPYLENE OXIDE AND ETHYLENE OXIDE PREPARED BY DOUBLE METAL CYANIDE COMPLEX CATALYST

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Chinese Journal of polymer science 2002年第5期20卷 453-459页

作者： Yi-jun Huang Guo-rong Qi Guan-xi Chen department of polymer science and engineering, zhejiang university hangzhou 310027,china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.

关键词： propylene oxide ethylene oxide double metal cyanide complex

RING-OPENING polymerIZATION OF TRIMETHYLENE CARBONATE BY CALIX[8]ARENE-NEODYMIUM

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Chinese Journal of polymer science 2000年第1期18卷 77-80页

作者： Ling Ge Zhi-quan shen Yi-feng Zhang Qiao-hong Huang department of polymer science and engineering, zhejiang university, hangzhou 310027, china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Ring-opening polymerization of trimethylene carbonate (TMC) with a rare earth calixarene compound as catalyst has been studied for the first time. The effect of TMC/Nd (molar ratio) and polymerization conditions were investigated in detail. It was found that calix[8]arene-neodymium is a highly effective catalyst for the bulk polymerization of TMC and gives high molecular weight (M-v = 60,000) polymer. The optimum conditions of TMC polymerization were found to be as follows:TMC/Nd (molar ratio) = 2,000, 80 degrees C, 16 h. The polymers were characterized by NMR, GPC and DSC. Studying the mechanism by NMR showed that the polymerization of TMC catalyzed by calix[8]arene-neodymium proceeds via a cationic mechanism.

关键词： ring-opening polymerization trimethylene carbonate calixarene-neodymium

STEREOCHEMICAL CONTROL IN PROPYLENE polymerIZATION CATALYZED BY UNBRIDGED METALLOCENE CATALYSTS

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Chinese Journal of polymer science 2001年第4期19卷 407-413页

作者： Yin-bang Zhu Zhi-qiang Fan Tariq Yasin Lin-xian Feng department of polymer science and engineering zhejiang university hangzhou 310027, china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Two unbridged metallocene catalysts, bis(2,4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2,4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six-membered ring of the indenyl ligands were synthesized. The effect of substituents in the two metallocenes on the propylene polymerization was studied in the presence of methylaluminoxane (MAO) and triisobutylaluminium (TIBA). From the analysis of microstructure determined by C-13-NMR, it was demonstrated that the polymers produced by met-II have higher [mmmm] isotactic sequences than that of met-I. Using a mechanism based on model statistical analysis, it was found that chain-end model was dominant for met-I. However, met-II obeys the concurrent two-sites model during polymerization, which can be attributed to the existence of 'racemic-like' conformer in its system.

关键词： unbridged metallocene propylene polymerization elastomeric polypropylene stereochemical mechanism

Design of a novel low power 8-transistor 1-bit full adder cell

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Journal of zhejiang university-science C(Computers and Electronics) 2011年第7期12卷 604-607页

作者： Yi WEI,Ji-zhong shen (department of Information science and Electronic engineering,zhejiang university,hangzhou 310027,china) department of Information science and Electronic engineering Zhejiang University

An addition is a fundamental arithmetic operation which is used extensively in many very large-scale integration (VLSI) systems such as application-specific digital signal processing (DSP) and *** adder determines the overall performance of the circuits in most of those *** this paper we propose a novel 1-bit full adder cell which uses only eight *** this design,three multiplexers and one inverter are applied tominimize the transistor count and reduce power *** power dissipation,propagation delay,and power-delay produced using the new design are analyzed and com-pared with those of other designs using HSPICE *** results show that the proposed adder has both lower power consumption and a lower power-delay product (PDP) *** low power and low transistor count make the novel 8T full adder cell a candidate for power-efficient applications.

关键词： Full adder design Low power CMOS circuit Very large-scale integration (VLSI)

Miktoarms hyperbranched polymer brushes:One-step fast synthesis by parallel click chemistry and hierarchical self-assembly

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science china Chemistry 2010年第12期53卷 2461-2471页

作者： HAN Yi & GAO Chao MOE Key Laboratory of Macromolecular Synthesis and Functionalization department of polymer science and engineering,zhejiang university,hangzhou 310027,china 1. MOE Key Laboratory of Macromolecular Synthesis and Functionalization department of polymer science and engineering Zhejiang University Hangzhou 310027 China

Spherical molecular brushes with amphiphilic heteroarms were facilely synthesized by grafting the arms of hydrophobic 2-azidoethyle palmitate and hydrophilic monoazide-terminated poly(ethylene glycol) onto the core of alkyne-modified hyperbranched polyglycerol (HPG) with high molecular weight (Mn=122 kDa) via one-pot parallel click *** parallel click grafting strategy was demonstrated to be highly efficient (～100%),very fast (～ 2 h) and well controllable to the amphilicity of molecular *** adjusting the feeding ratio of hydrophobic and hydrophilic arms,a series of brushes with different arm ratios were readily *** resulting miktoarms hyperbranched polymer brushes (HPG-g-C16/PEG350) were characterized by hydrogen-nuclear magnetic resonance (1H NMR),Fourier transform infrared (FT-IR) spectroscopy,gel permeation chromatography (GPC),and differential scanning calorimetry (DSC) *** spherical molecular brushes showed high molecular weights up to 230 kDa,and thus could be visualized by atomic force microscopy (AFM).AFM and dynamic laser light scattering (DLS) were employed to investigate the self-assembly properties of amphiphilic molecular brushes with closed proportion of hydrophobic and hydrophilic *** brushes could self-assemble hierarchically into spherical micelles,and network-like fibre structures,and again spherical micelles by addition of n-hexane into the dichloromethane or chloroform solution of *** addition,this kind of miktoarms polymer brush also showed the ability of dye loading via host-guest encapsulation,which promises the potential application of spherical molecular brushes in supramolecular chemistry.

关键词： miktoarms molecular brushes hyperbranched polyglycerol amphiphilic self-assembly

Dynamic behavior of polymer surface and the time dependence of contact angle

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science china Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & shen Zhiquan2 1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, department of Applied Chemistry, zhejiang Institute of science and Technology, hangzhou 310033, china 2. department of polymer science and engineering, zhejiang university, hangzhou 310027, china 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of polymer science and engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

polymerIZATION OF p-DIETHYNYLBENZENE INITIATED BY Ni(C≡CC_6H_4C≡CH)_2(PPH_3)_2

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Chinese Journal of polymer science 2001年第3期19卷 303-309页

作者： Mu-jie Yang Xiao-wei Zhan department of polymer science and engineering zhejiang university hangzhou 310027, china Present address: Institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china 浙江大学浙江杭州

Homogeneous polymerization of p-diethynylbenzene initiated by nickel acetylide Ni(C ≡ C C_6H_4 C ≡ CH)_2(PPh_3)_2has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomerconcentrations and polymerization temperatures. The yield and catalytic efficiency approach 88% and 11. 1 kg polymer/molNi, respectively, under the optimum conditions: [cat] = 0.01 mol/L, [M] = 1.0 mol/L, NEt_3/cat (mol ratio) = 3～5, 1,4-dioxane/toluene (volume ratio) = 1 and T = 25℃ for 5 h. The polymerization rate equation can be expressed as R_p =k_p[M][cat]~2, where k_p= 0.47 L^2. mol^(-2)·S^(-1) (25℃). The overall polymerization activation energy was found to be203 kJ·mol^(-1). Poly(p-diethynylbenzene) so obtained is soluble in THF, CHCl_3 and toluene with weight-average molecularweights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups ofp-C_6H_4C≡CH.

关键词： polymerization p-Diethynylbenzene Nickel acetylide Catalyst