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Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

Science China Chemistry 2009年第11期52卷 1843-1850页

作者： XiongFa Yang XuFeng Ni ZhiQuan Shen Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Institute of Polymer Science Zhejiang University Hangzhou 310027 China

The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H2salen)2Cl3·2C2H7OH/Al(i-Bu)3) at room temperature was investigated. The influences of ligand str... 详细信息

The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H₂salen)₂Cl₃·2C₂H₇OH/Al(i-Bu)₃) at room temperature was investigated. The influences of ligand structure, catalyst composition, polymerization temperature, polymerization time, the concentration of catalyst and monomer, and the polymerization solvent on the polymerization of isocyanates were studied. It was found that under the polymerization conditions, examined La(H₂salen_A)₂Cl₃·2C₂-H₇OH/Al(i-Bu)₃ (H₂salen_A= N,N′-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature. PHNCO could be prepared with yield of 74.0%, number-average molecular weight (M _n) of 40.20×10⁴ and MWD of 1.79 under the following optimum conditions: [Al]/[La] = 30 (molar ratio), [n-HexNCO]/[La] = 100 (molar ratio), [n-HexNCO] = 3.43 mol/L polymerization at 20°C for 12 h in toluene. In the same polymerization conditions, poly (n-octyl isocyanate) (PONCO) with yield of 67.3%, and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%, could be prepared respectively. The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.

关键词： rare earth catalyst Schiff base complex polymerization alkyl isocyanate

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Honeycomb-patterned films of polystyrene/poly(ethylene glycol): Preparation, surface aggregation and protein adsorption

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Science China Chemistry 2009年第7期52卷 969-974页

作者： WAN LingShu KE BeiBei LI XiaoKai MENG XiangLin ZHANG LuYao XU ZhiKang Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Institute of Polymer Science and State Key Laboratory of Chemical EngineeringZhejiang UniversityHangzhou 310027China

Highly ordered honeycomb-patterned polystyrene (PS)/poly(ethylene glycol) (PEG) films were prepared by a water-assisted method using an improved setup, which facilitated the formation of films with higher regularity, better reproducibility, and larger area of honeycomb structures. Surface aggregation of hydrophilic PEG and adsorption of bovine serum albumin (BSA) on the honeycomb-patterned films were investigated. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to observe the surface morphologies of the films before and after being rinsed with water. As confirmed by the FESEM images and the AFM phase images, PEG was enriched in the pores and could be gradually removed by water. The adsorption of fluorescence-labeled BSA on the films was studied in visual form using laser scanning confocal microscopy. Results clearly demonstrated that the protein-resistant PEG was selectively enriched in the pores. This water-assisted method may be a latent tool to prepare honeycomb-patterned biofunctional surfaces.

关键词： honeycomb-patterned film water-assisted method polystyrene poly(ethylene glycol) surface aggregation

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Covalently immobilized gelatin gradients within three-dimensional porous scaffolds

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Chinese Science Bulletin 2009年第18期54卷 3174-3180页

作者： WU JinDan TAN HuaPing LI LinHui GAO ChangYou Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education and Department of Science and Engineering Zhejiang University Hangzhou 310027 China

A stable gelatin gradient providing continuous increment of signaling for cell adhesion and proliferation was fabricated within 3D poly(L-lactic acid) (PLLA) scaffolds. The porous PLLA scaffold fabricated by NaCl particle leaching was vertically fixed on a glass vial. 1,6-Hexanediamine/propanol solution was continuously injected into the vial by a micropump to aminolyze the PLLA scaffold. As a result of reaction time difference, the introduced -NH2 groups increased continuously along with the longitude of the PLLA scaffold in the z-direction. After covalent immobilization of gelatin by glutaraldehyde coupling, the gelatin gradient scaffold was thus obtained. In vitro chondrocyte culture showed that the cells had higher viability and more extending morphology in the gelatin gradient scaffold than that in the uniform gelatin control.

关键词：多孔支架共价固定明胶梯度三维细胞粘附聚乳酸金属制品

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ELECTROSPRAYING/ELECTROSPINNING OF POLY(γ-STEARYL-LGLUTAMATE):FORMATION OF SURFACES WITH SUPERHYDROPHOBICITY

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Chinese Journal of Polymer Science 2009年第1期27卷 115-120页

作者：吴健徐志康 Department of Chemistry Zhejiang University Institute of Polymer Science and Key Laboratory of Macromolecular Synthesis and Functionalization (Ministry of Education)Zhejiang University

Electrospraying/electrospinning of poly(γ-stearyl-L-glutamate) (PSLG) was investigated on a series solutions with different concentrations in *** emission scanning electron microscopy (FESEM) and attenuated Iotal reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) were used to characterize the morphology and structure of the electrosprayed/electrospun polypeptide *** was found that electrospraying of PSLG with concentrations lower than 16 wt% afforded beads,while microfibers cou...

关键词： Electrospinning/electrospraying Poly（γ-stearyl-L-glutamate） Polypeptide Water contact angle Superhydrophobic surface

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synthesis,structure and catalytic activity of complexes [Ln(EDBP)_2(DME)Na(DME)_3](Ln=Er,Yb,Sm) for ring-opening polymerization of ε-caprolactone

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Science China Chemistry 2009年第10期52卷 1711-1714页

作者： YU JianFang, WU GuangMing, HUANG Jing, SUN WeiLin & SHEN ZhiQuan key laboratory of macromolecular synthesis and functionalization, Ministry of Education, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China 1. Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Discrete ion-pair complexes [Ln(EDBP)2(DME)Na(DME)3] [Ln=Er (1), Yb (2), Sm (3)] have been synthesized by the reaction between sodium salt of 2,2'-ethylidene-bis(4,6-di-tert-butylphenol)(EDBPH2) and Ln(BH4)3·3THF (Ln=Er, Yb, Sm) followed by centrifugation and recrystalization. The complexes were characterized by elemental analysis and FT-IR, and the bonding model of these compounds was confirmed by X-ray single crystal diffraction for complex 1. It was found that four O atoms in two biphenol ligands as well as two O atoms in one ethylene glycol dimethyl ether (DME) molecule connect to the center rare earth metal atom, while sodium exists as counterpart cation to balance the charge. Complexes 1―3 can all be used as single component initiators for the ring-opening polymerization of ε-caprolactone.

关键词： ring-opening polymerization ε-caprolactone X-ray single crystal biphenol

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Large enhancements in gelation behavior of wheat gliadins by incorporation of low concentrations of methylcellulose

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Chinese Chemical Letters 2009年第5期20卷 623-626页

作者： Yi Hu Song Ling Fang Li Qiang Zheng Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Zhejiang University Hangzhou 310027 China

Influence of non-gelling methylcellulose （MC） on gelation behavior of wheat gliadins in 13 wt% alkaline propanol/water （50：50, v/v） solution was investigated using dynamic theological time sweep test. Increasing MC concentration （CMC） up to CMC = 1 wt% caused a significant reduction in gelation time （tget） of the solution and an increase in loss tangent （tan δ） value of the resultant gel at T 〈 30 ℃.

关键词： Gliadin Gelation Rheology Methylcellulose （MC）

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Preparation and properties of wheat gluten/silica composites

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Science China Chemistry 2009年第3期52卷 257-260页

作者： SONG YiHu ZHENG Qiang ZHOU WenCe Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310027China Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Zhejiang UniversityHangzhou 310027China

Wheat gluten (WG)/silica (SiO2) hybrids were prepared through in-situ synthesis of SiO2 in WG disper-sion of aqueous ammonia. The hybrids with different SiO2 contents were mixed with glycerol plasticizer to form cohesive dough and the dough was compressively molded to form cross-linked sheets. Morphology, moisture absorption, protein solubility in water, tensile mechanical properties and dynamic rheological behavior of the WG/SiO2 composites were investigated in relation to SiO2 contents.

关键词： wheat gluten silica composites properties

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Surface modification of acrylate intraocular lenses with dielectric barrier discharge plasma at atmospheric pressure

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Science China Chemistry 2009年第8期52卷 1235-1243页

作者： WANG Yao LIU ZhenMei XU ZhiKang YAO Ke Institute of Ophthalmology and Eye Center Affiliated Second HospitalCollege of MedicineZhejiang UniversityHangzhou 310009China Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Institute of Polymer ScienceZhejiang UniversityHangzhou 310027China

Surface modification with dielectric barrier discharge(DBD) plasma was carried out at atmospheric pressure(argon as the discharge gas) to improve the biocompatibility of hydrophobic acrylate intraocular lens(IOL).Changes of the plasma-treated IOL surface in chemical composition,morphology and hydrophilicity were comprehensively evaluated by X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM) and water contact angle(WCA) *** surface biocompatibility of the untreated and plasma-treated IOLs was compared with the adhesion behavior of platelets,macrophages and lens epithelial cells(LECs) in *** DBD plasma treatment,the hydrophilicity of the IOL surface was obviously *** changes in WCA with treatment extension may be attributed to both the introduction of oxygen or/and nitrogen-containing polar groups and the increase of surface roughness induced by plasma etching *** existence of low molecular weight oxidized material(LMWOM) was proved on the plasma-treated IOL which was caused by the chain scission effect of the plasma *** plasma-treated IOLs resisted the adhesion of platelets and macrophages *** LECs spreading and proliferation were postponed on the IOLs plasma-treated for more than 180 s,with a well maintained epithelial phenotype of *** IOL biocompatibility was improved after the DBD plasma *** speculate that slighter foreign-body reaction and later incidence of anterior capsule opacification(ACO) may be expected after implantation of the argon DBD plasma-treated IOL.

关键词： hydrophobic acrylate intraocular lens surface modification dielectric barrier discharge plasma at atmospheric pressure biocompatibility surface property

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synthesis OF A HYPERBRANCHED POLY(AROYLARYLENE) CONTAINING TRIAZOLE AND FLUORENE FUNCTIONALITIES BY CLICK CHEMISTRY AND METAL-FREE,REGIOSELECTIVE POLYCYCLOTRIMERIZATION

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Chinese Journal of Polymer Science 2009年第2期27卷 145-148页

作者： Cathy K.W.Jim Jacky W.Y.Lam 唐本忠 Department of Chemistry The Hong Kong University of Science & TechnologyClear Water BayKowloonHong KongChina Department of Polymer Science and Engineering Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of EducationZhejiang University

A new bis(aroylacetylene) containing tfiazole and fluorene moieties is synthesized by click chemistry. Polycyclotrimerization of the monomer is catalyzed by piperidine in refluxed dioxane,furnishing a regioregular poly(aroylarylene) in a satisfactory *** hyperbranched structure of the polymer is characterized spectroscopically with satisfactory *** polymer enjoys no metal detriment and is soluble in common organic solvents such as tetrahydrofuran (THF),chloroform,dichloromethane (DCM),and N,N-...

关键词： Regioregular Click chemistry Polycyclotrimerization Hyperbranched polymer.

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STUDIES ON RELATION BETWEEN INTRINSIC VISCOSITY OF POLYELECTROLYTES IN SOLUTIONS USED FOR LAYER-BY-LAYER SELFASSEMBLY AND THEIR CORRESPONDING ADSORPTION AMOUNTS IN THE RESULTANT MULTILAYER MEMBRANES

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Chinese Journal of Polymer Science 2009年第3期27卷 297-306页

作者：钱锦文安全福 Phillip Choi Department of Polymer Science & Engineering Key Laboratory of Macromolecular Synthesis and Functionalization(Ministry of Education)Zhejiang University Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaCanada T6G 2G6

The adsorption amount of poly(styrene sulfonate) and poly(dimethyldiallyl ammonium chloride) (PSS/PDDA) self-assembled multilayer membranes in designed dipping solvents were measured by UV-Vis-spectroscopy and quartz crystal microbalance (QCM). Intrinsic viscosities of PSS and PDDA in corresponding dipping solvents were determined by an Ubbelohde viscometer. It is found that the adsorption amount of PSS/PDDA self-assembled multilayer membranes built up in different dipping solutions, added salt concentration, pH of solution and solvent quality, respectively changed oppositely with the corresponding intrinsic viscosity of PSS and PDDA in dipping solvents. A negative relation between the adsorption amount and intrinsic viscosity was revealed, and explained in term of the concept of excluded volume of polymer molecule in dilute solutions.

关键词： Self-assembled multilayer membrane PSS/PDDA Polyelectrolyte solution Intrinsic viscosity

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