Preparation and characterization of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands by modified suspension polymerization

A novel preparation method of micron‐sized non‐porous magnetic polymer microspheres with immobilized metal affinity ligands was developed. A modified suspension polymerization of methacrylate (MA) and divinylbenzene (DVB) was performed in the presence of oleic acid‐coated magnetic Fe₃O₄ nanoparticles to obtain magnetic poly (methacrylate‐divinylbenzene) (mPMA‐DVB) microspheres. Through ammonolysis using ethylenediamine (EDA) and subsequent carboxymethylation with chloroacetic acid, magnetic polymer microspheres with chelate ligands of iminodiacetic acid (IDA) were obtained. Charging with copper ions resulted in magnetic polymer microspheres capable of binding proteins that display metal affinity. The morphology, magnetic properties, and composition of magnetic polymer microspheres were characterized with scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR), respectively. Bovine hemoglobin (BHb) was adopted as a model protein to investigate their affinity adsorption capacity. It was found that the adsorption capacity was as high as 168.2 mg/g microspheres and with rather low non‐specific adsorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2174–2180, 2005     

Synthesis of Composite Nanoparticles Bearing Epoxy Functional Groups：Encapsulation of Silica by Emulsion Polymerization of GMA

Poly （ glycidyl methacrylate ） / silica （PGMA/silica） composite nanoparticles , containing epoxy functional groups on the surface, were synthesized via emulsion polymerization. With batch process, high yield and binding efficiency （ both around 90% ） were achieved. The amount of crosslinked GMA was approximately 8wt%- 14wt% to the polymerized monomer. It was found that both the encapsulating ratio and the number of the original silica beads per composite particles altered with the amount of silica added. The obtained particles, with their average particle size of about 60- 70 nm, had a spherical shape and a clear core- shell structure.     

多巴胺的自聚-附着行为与膜表面功能化

多巴胺(dopamine)是一种生物神经递质,在水溶液条件下,它能在溶解氧的作用下发生氧化-交联反应,形成强力附着于固体材料表面的聚多巴胺复合薄层.基于多巴胺的这一特性,近年来膜技术研究者们通过多巴胺在固体基膜上的自聚-复合,对膜进行表面改性,并以具有反应活性的聚多巴胺复合层为平台,对膜进行进一步的表面修饰,实现膜的功...     

Preparation and characterization of chloroacetylated polystyrene‐supported zinc complexes and evaluation of their catalytic activities for the synthesis of 1,1‐diacetates

Zinc chloride was immobilized onto chloroacetylated polystyrene via different linkages to afford polymer‐supported Lewis acid catalysts. The functionalized beads and the immobilized catalysts were characterized by elemental analysis, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and inductively coupled plasma and thermal analysis. The reaction of aldehydes with anhydride in the presence of the supported catalysts was investigated. The effects of various parameters, including the solvent, amount of catalyst, and temperature, on the reaction were also studied. We found that the reaction proceeded smoothly under solvent‐free conditions at room temperature and afforded the corresponding acylals in good yields. Moreover, the catalysts could be recovered easily and reused several times without a significant loss in activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

PtRu nanoparticles supported on nitrogen-doped multiwalled carbon nanotubes as catalyst for methanol electrooxidation

Nitrogen-doped carbon nanotubes (N-CNT) obtained by plasma treatment were compared to the conventional acid-treated carbon nanotubes (O-CNT) as catalyst support for platinum-ruthenium (PtRu) nanoparticles in the anodic oxidation of methanol in direct methanol fuel cells. PtRu catalysts were prepared by an impregnation-reduction method from chloride precursors with metal loadings of 20 wt.%, and were characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical methods. Voltammetry and chronoamperometry studies showed that the performance of PtRu/N-CNT was significantly higher compared to PtRu/O-CNT and also to the commercial E-TEK PtRu/C catalyst, indicating that N-CNT are an interesting support material for fuel cell electrocatalyst. Nitrogen plasma treatment produced pyridinic and pyrrollic species on the CNT surface, which acts as the anchoring sites for the deposition of PtRu particles. A mechanism for the deposition of PtRu on N-CNT is tentatively proposed and discussed.     

Modulation of Lumen Formation by Microgeometrical Bioactive Cues and Migration Mode of Actin Machinery

How endothelial cells (ECs) express the particular filopodial or lamellipodial form of the actin machinery is critical to understanding EC functions such as angiogenesis and sprouting. It is not known how these mechanisms coordinately promote lumen formation of ECs. Here, adhesion molecules (RGD peptides) and inductor molecules (BMP‐2 mimetic peptides) are micropatterned onto polymer surfaces by a photolithographic technique to induce filopodial and lamellipodial migration modes. Firstly, the effects of peptide microgeometrical distribution on EC adhesion, orientation and morphogenesis are evaluated. Large micropatterns (100 μm) promote EC orientation without lumen formation, whereas small micropatterns (10–50 μm) elicit a collective cell organization and induce EC lumen formation, in the case of RGD peptides. Secondly, the correlation between EC actin machinery expression and EC self‐assembly into lumen formation is addressed. Only the filopodial migration mode (mimicked by RGD) but not lamellipodial migration mode (mimicked by BMP‐2) promotes EC lumen formation. This work gives a new concept for the design of biomaterials for tissue engineering and may provide new insight for angiogenesis inhibition on tumors.     

Acid‐dye‐dyeable polyacrylonitrile/ poly(N,N‐dilkylaminoethylacrylate) acrylic blend fiber

An acid‐dye‐dyeable polyacrylonitrile/poly (N,N‐dilkylaminoethylacrylate) blend fiber was prepared. On the basis of research for the dye uptake, color strength, tensile strength, and breaking elongation of the polyacrylonitrile/poly (N,N‐dilkylaminoethylacrylate) blend fiber, it was found that the blend fiber and its fabrics for acid dyes possessed favorable dyeability and mechanical properties. The effect of the polyacrylonitrile ratio on the blend fiber was examined. The optimum dyeing‐process parameters were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Reversible addition–fragmentation chain transfer polymerization of styrene using a novel thiophene dithioester as the reversible addition–fragmentation chain transfer agent

Benzyl thiophene‐2‐carbodithioate and 2‐methyl‐2‐(4‐methylcyclohex‐3‐enyl)propyl thiophene‐2‐carbodithioatewere synthesized. The reversible addition–fragmentation chain transfer polymerizations of styrene with benzyl thiophene‐2‐carbodithioate and 2‐methyl‐2‐(4‐methylcyclohex‐3‐enyl)propyl thiophene‐2‐carbodithioate as chain‐transfer agents and with 2,2′‐azobisisobutyronitrile as an initiator were carried out. The polymerization kinetics were investigated. An ab initio calculation method was used to explore the differences between benzyl thiophene‐2‐carbodithioate and benzyl benzodithioate. The structure of the obtained polymers was characterized with ¹H‐NMR. Chain‐extension experiments of the obtained polymer with styrene were carried out. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Mesoporous ordered silica structures modified by metal organic reagents and their application in catalytic Michael additions

Periodic mesoporous silica was modified with metal organic reagents via direct surface substitution reactions, thus introducing functional groups into the channels of the structure. Using materials functionalised with basic aromatic molecules as catalysts, the efficient Michael addition of diethyl malonate to trans-β-nitrostyrene was achieved. The catalysts anchored to the silica surface show high activity in the catalytic process even at low concentrations and low temperatures. The catalysts also prove to be stable during many recycling procedures. In combination with the remarkably reduced cost for the synthesis of these solid bases, the new hybrid systems are promising candidates for a new generation of catalysts.     

Properties of amine‐containing coatings prepared by plasma polymerization

Two monomers, ethylenediamine (EDA) and diaminocyclohexane (DACH), were plasma‐polymerized in continuous‐wave (CW) and pulse modes. The influence of different plasma parameters on the deposition rate and film composition were investigated in detail and the changes in aminofunctionalization with varying pulse parameters were examined by FTIR, ESCA, and chemical‐derivatization techniques. It was shown that a varying duty cycle does not produce a considerable effect on the retention of amine groups into the film, while power and t_on play a significant role in the polymerization process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 979–990, 2004