Synthesis and Adsorption Property of Two Polymeric Adsorbents with Pendent Ether Bonds

Two polymeric adsorbents, poly(methyl p-vinylbenzvl ether) and oolv(ohenvl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene, Their adsorptionproperty for phenol in hexane solution was investigated. The results showed that the twoadsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.     

Synthesis of Thiourea Derivatives on Soluble Polymeric Support

A modified poly(ethylene glycol) (PEG) has been developed as the soluble polymeric supports for liquid phase synthesis of novel thiourea derivatives.In each step of the sequence,the PEG-bound products were precipitated in cold Et2O and the unreacted materials and by-products were removed by simple filtration.The progress of reaction,purity of the isolation and the structure of the PEG-bound products were easily monitored by TLC,IR and ^1H NMR spectra.Representative thiourea derivatives were obtained in moderate yields with excellent purity from this modified PEG-bound product by the cleavage with 50% TFA/H2O.     

Online Separation and Preconcentration of Gold and Palladium on Amidinothiourea Immobilized Glass Bead for Interference-Free Flame Atom Absorption Spectrometry Determination

Amidinothiourea immobilized glass bead (AGB) was applied as the microcolumn packing for the flow-injection online separation and preconcentration of Au(III) and Pd(II) coupled with FAAS determination. The peak-area absorbance (A) and the peak-height absorbance (H) were all used as the evaluating modes. Au(III) and Pd(II) in 0.50 M HCl solution were absorbed onto AGB completely and then eluted into AAS with thiourea solution. Base metal ions with a concentration of 2.0 mg/mL and anions with a concentration of 20.0 mg/mL caused no interference in the determination of Au(III) and Pd(II). The LODs of Au(III) and Pd(II) for a preconcentration time of 60 s with a sampling flow rate of 5.0 mL/min for 0.20 μg/mL of Au(III) and 0.30 μg/mL of Pd(II) were 2.7 and 6.5 ng/mL with the H mode and 4.6 and 10.2 ng/mL with the A mode, respectively. The RSD of seven replicate determinations of 0.20 μg/mL of Au(III) and 0.30 μg/mL of Pd(II) were 0.018 and 0.024 for the H mode and 0.013 and 0.018 for the A mode, respectively. The method was successfully applied to the determination of Au and Pd in real samples. __________ From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 10, 2005, pp. 1023–1029. Original English Text Copyright ? 2005 by Liu, Pu, Su. The text was submitted by the authors in English.     

Hyperbranched poly(ether amine)(hPEA)as novel backbone for amphiphilic one-component type-Ⅱ polymeric photoinitiators

A series of amphiphilic polymeric photoinitiators with hyperbranched poly(ether amine) (hPEA) as novel backbone were developed, which can initiate photopolymerization of water-soluble and hydrophobic monomers very efficiency and might have great potential applications in the field of photo-curing.     

Synthesis and Characterization of Poly（ether amide）s Containing Bisphthalazinone and Ether Linkages

A novel aromatic diacid, 4, 4′-bis[2-(4-carboxyphenyl)phthalazin- 1-one-4-yl]-bisphenyl ether III, containing bisphthalazinone and ether linkages was prepared from nucleophilic substitution of p-chlorobenzonitrile with the bisphenol-like monomer I, followed by alkaline hydrolysis of the intermediate dinitrile II. A series of poly(ether amide)s containing bisphthalazinone and ether linkages derived from diacid III and aromatic diamines were synthesized by one-step solution condensation polymerization using triphenyl phosphite and pyridine as condensing agents. Moreover, the properties of poly(ether amide)s including thermal stability,solubility and crystallinity were also studied.     

Synthesis and characterization of new soluble poly（aryl ether nitrile）s containing phthalazinone moiety

A series of novel poly（aryl ether nitrile）s containing phthalazinone moiety were synthesized by the nucleophilic displacement reaction of bisphenol-like monomers （I） with 2,6-difluorobenzonitrile. The inherent viscosities ranged from 0.46 to 1.07 dL g^-1. The glass transition temperatures were in the range of 277-295℃, and the temperatures for 10% weight loss in nitrogen atmosphere were found between 495 and 527 ℃. The structures of these resultant polymers were confirmed by FT-IR and 1^H NMR. Moreover, the properties of poly（aryl ether nitrile）s including solubility and crystallinity were also studied.     

Hyperbranched Polymeric Fluorosurfactants:Synthesis,Surface Activity and Their Application in Firefighting Foams

Fluorosurfactants are the key ingredients in the formulations of aqueous film-forming foams(AFFFs) for extinguishing flammable liquids,thus developing high-efficient and low-toxic fluorosurfactants is desirable in AFFFs application.Herein,a series of hyperbranched polymeric fluorosu rfactants(HPFs) were successfully synthesized through sequentially modifying hyperbranched polyethylenimine(PEI) with the hydrophilic poly(ethylene glycol)(PEG) chains and the hydrophobic C6/C4-based perfluoroalkyl c...     

Synthesis,curing and properties of poly(phthalazione ether sulfone ketone) copolymers crosslinked by click chemistry

Functionalized poly(phthalazinone ether sulfone ketone) was synthesized by successive chloromethylation and azidation, followed by curing reaction with the propargyl end-groups of various molecular weight crosslinking agents in the presence of Cu(Ⅰ) catalyst via the azide-alkyne click reaction. The influences of the chain length of crosslinking agents on the poly(phthalazinone ether sulfone ketone) system were studied. FTIR and DSC tests demonstrated certain crosslinking by azide-alkyne reaction with the formation of triazole ring. DSC results showed that curing temperature shifted to lower temperatures considerably in the presence of Cu(Ⅰ) catalyst. TGA showed cured polymers were of much higher thermal stability, including higher thermal decomposition temperatures and higher char-yielding properties. After being cured, the polymers became insoluble in organic solvents and the gel fraction of the cured polymers exceeded 71%. Wide-angle X-ray diffraction results indicated there was a short distance order in the poly(ether sulfone)(PES) main chain except for the azido methyl poly(phthalazinone ether sulfone ketone) and 4,4'-bis(2-propynyloxy) biphenyl( AMPPESK-BP) system.     

Poly(1-vinylimidazole) Prospects in Gene Delivery

Polymeric amines are being studied intensively as components of systems for gene delivery in genetic engineering and gene therapy of genetic disorders, including cancer. Despite remarkable achievements in the field, polymeric amines, such as polyethyleneimine, show some disadvantages. Strong interaction between the amine-containing polymer and nucleic acid hampers the release of nucleic acid in the cell cytoplasm. Amine groups can interact with the cell membrane which results in cell death. These limitations of polymeric amines stimulated an investigation of new structures for gene delivery. Imidazole-containing polymers have attracted attention as lesser basic substances, while they are able to interact with polymeric acids. Further development of imidazole-based gene delivery agents requires knowledge about some fundamental aspects of interaction between nucleic acids, and polymeric imidazoles. In this work, we studied the complexation of poly(1-vinylimidazole) and oligomeric DNA. We found that the number of active sites capable of binding with negatively charged phosphate groups is comparable with the number of protonated imidazole units in the case of high molecular weight polymer. The increase in polymer charge by 1-bromopropane quaternizating 1%?5% imidazole units or by decreasing the pH to 6.5?7 considerably increased the ability of poly(1-vinylimidazole) to interact with oligonucleotides. The pH sensitivity of this interaction is interesting for cancer gene therapy because the tumours have a lowered intercellular pH (stable oligonucleotide complex) and a higher extracellular pH which can lead to complex dissociation. Minimal critical length for complexation of quaternized poly(1-vinylimidazole) and DNA is below eight units which corresponds to polymers with amine groups. Fluorescence-tagged poly(1-vinylimidazole) samples were obtained and their potential for monitoring the polymer and polymer-oligonucleotide complex internalization into living cells was demonstrated.     

Base-free aerobic oxidation of glycerol on TiO_2-supported bimetallic Au–Pt catalysts

The aerobic oxidation of glycerol provides an economically viable route to glyceraldehyde, dihydroxyacetone and glyceric acid with versatile applications, for which monometallic Pt, Au and Pd and bimetallic Au–Pt, Au–Pd and Pt–Pd catalysts on Ti O2 were examined under base-free conditions. Pt exhibited a superior activity relative to Pd, and Au–Pd and Pt–Pd while Au was essentially inactive. The presence of Au on the Au–Pt/Ti O2 catalysts led to their higher activities(normalized per Pt atom) in a wide range of Au/Pt atomic ratios(i.e.1/3–7/1), and the one with the Au/Pt ratio of 3/1 exhibited the highest activity. Such promoting effect is ascribed to the increased electron density on Pt via the electron transfer from Au to Pt, as characterized by the temperature-programmed desorption of CO and infra-red spectroscopy for CO adsorption. Meanwhile,the presence of Au on Au–Pt/Ti O2, most like due to the observed electron transfer, changed the product selectivity, and facilitated the oxidation of the secondary hydroxyl groups in glycerol, leading to the favorable formation of dihydroxyacetone over glyceraldehyde and glyceric acid that were derived from the oxidation of the primary hydroxyl groups. The synergetic effect between Au and Pt demonstrates the feasibility in the efficient oxidation of glycerol to the targeted products, for example, by rational tuning of the electronic properties of metal catalysts.     

Adsorption and Dissociation of Methanol on Pd(111), Pd/Au(111) and Pd/Rh(111) Surfaces

The adsorption and dissociation behaviors of methanol on Pd(111), Pd/Au(111) and Pd/Rh(111) surfaces were studied using a periodical slab model and the PW91 generalized gradient approximation(GGA) within the framework of first-principles calculations based on density functional theory(DFT). The adsorption energy and geometric parameters for the three surfaces showed that methanol is preferentially adsorbed onto the top-Pd sites and that the adsorption energy of methanol on these surfaces decreases in the order Pd/Au(111) Pd/Rh(111) Pd(111). After adsorption, the C–O, C–H and O–H bonds in methanol adsorbed onto these surfaces are elongated and the vibrational stretching frequency of the O–H bond is obviously redshifted. Furthermore, the first step for the possible dissociation pathway for methanol on these surfaces was calculated. Our results indicate that the O–H bond in methanol decomposes producing methoxy and a hydrogen atom, with the Pd/Au(111) surface exhibiting the smallest dissociation barrier.     

Heat treatment bimetallic PdAu nanocatalyst for oxygen reduction reaction

Pd-based nanocatalyst is a potential oxygen reduction oxidation(ORR)catalyst because of its high activity in alkaline medium and low cost.In this work,bimetallic Pd Au nanocatalysts are prepared by one-pot hydrothermal method using triblock pluronic copolymers,poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)(PEO_(19)-PPO_(69)-PEO_(19))(P123)as reducer and stabilizer,and heat-treatment method is applied to regulate catalyst structure and improve catalyst activity.The results show that the heat treatment can agglomerate the catalyst to a certain extent,but effectively improve the crystallinity and alloying degree of the catalyst.The ORR performance of the Pd Au nanocatalysts obtained under different heat treatment conditions is systematically investigated.Compared with commercial Pd black and Pd Au catalyst before heat treatment,the ORR performance of Au Pd nanocatalyst obtained after heat treatment for one hour at 500°C has been enhanced.The Pd Au nanocatalysts after heat treatment also display enhanced anti-methanol toxicity ability in acidic medium.     

Polymer Surfactants a; Analytical Reagents——Synthesis of PPOTA and PPOCA and Their Analytical Properties

Two new polymer surfactants poly(propylene oxide)-a-tetradecyl-dimethylammonium chloride(PPOTA) and poly(propylene oxide)-a-cetyl-dimethylammonium chloride(PPOCA) were synthesized,which possess the characteristics of both cationic and nonionic surf actants.The properties of PPOTA and PPOCA were investigated.The synthesized surfactants can be used as sensitizing and solubilizing reagents for spectrophotometric analysis.Some examples of micellae improved by spectrophotometric systems such as Sc(Ⅲ)-CAS,Ge(Ⅳ)-PF and Ni(Ⅱ)-CAS were given.     

Mass Spectrometric Studies on Metal-hexafluorobenzene Anionic Complexes（M=Ag, Au, Pd, Pt, Pb and Bi）

The anionic products from the reactions between metal(M=Ag, Au, Pd, Pt, Pb and Bi) vapour produced by laser ablation and hexafluorobenzene seeded in carrier gas(Ar) were studied by means of a homemade reflectron time-of-flight mass spectrometry(RTOF-MS). Experimental results show that the dominant products were [MmC6F6]-complexes for the reactions of Ag, Au, Pd and Pt with C6F6, while the dominant products were [MmC6F5]-complexes for the reactions of Pb and Bi with C6F6. The formation mechanisms of the prod...     

Flexible Gradient Poly(ether-ester) from the Copolymerization of Epoxides and ε-Caprolactone Mediated by a Hetero-bimetallic Complex

Copolymerization is a commonly employed method for optimizing the properties of polymer materials. Incorporating ether segments into polyesters main chain to obtain polyether-polyester copolymers is an effective strategy to realize the integration of multiple properties of polyester and polyether, and to develop more high-performance, multi-purpose polymer materials. Herein, the synthesis of poly(ether-ester)s is accessible by employing the biphenyl-linked heterodinuclear salen Cr-Al complex in the presence of PPNCl for the copolymerization of epoxides and ε-caprolactone(CL). Monitoring the copolymerization process reveals that catalyst 1 exhibited good performance for the copolymerization of epoxides and CL, affording copolymers with a gradient sequence structure. The dynamic thermomechanical analysis(DMA) study indicates the obtained poly(ether-ester)s possess enhanced flexibility compared with the block copolymers or blend of PPO and PCL homopolymers with the same ratio. This study provides a theoretical basis for the preparation of high-performance polymer materials.     

SYNTHESIS OF POLYMERS CONTAINING N-N LINKAGES

The N-N linkage in hydrazine is thermally stable when it is tetrasubstituted and there are electron-withdrawinggroups attached to the nitrogen atoms. Our research on the synthesis of polymers contaning N--N linkages is reviewed. TheN,N-bisimide structure has been introduced in the backbone of polymers as well as a pendant group in poly(aryl ether)s togive very thermoxidatively stable polymers with very high glass transition temperatures. Most of the polymers form tough,flexible films. N-Aminotriazoles also form stable imides by reaction with anhydrides and these N-imidotriazole groups havebeen introduced as pendent groups on poly(aryl ether)s. The polymers are highly fluorescent materials. Three methods for thesynthesis of polymers containing the tetrasubstituted-azine structure will be discussed: (1) oxidative coupling of bisimines;(2) condensation of bishydrazones with diketones; (3) poly(aryl ether azines) from the azine formed from 4-fluorobenzo-phenone by reaction with salts of bisphenols.     

PREPARATION AND MAGNETIC PROPERTIES OF POLY(SCHIFF BASE) COMPLEXES CONTAINING PHENANTHROLINE UNITS

Two poly(Schiff base)s (PDBT and PDPE) were synthesized by polycondensation of 1,10-phenanthroline-5,6- dione (PD) with 2,2′-diamino-4,4′-bithiazole (DABT) and 4,4′-diaminodiphenyl ether (DAPE),respectively.The structures of the polymers were determined by FTIR and element analysis.The metal (Fe~(2+),Ni~(2+)) complexes were prepared from the polymers with FeSO_4 or NiSO_4,and the metal contents of the complexes were measured by complexometric titration.The magnetic behaviors of the complexes were examine...     

Polymeric adsorbents with peptide pendants as artificial receptors for β-Mactam antibiotics by mimicking the binding sites of β-lactamases

A scries of polymeric adsorbents with peptide pendants were designed as the artificial receptors of β-laetarn antibiotics by mimicking the structures of binding site in β-lactamases.Crosslinked poly(N,N-dimethyl acry-lamide) gel as a carrier was prepared by suspension copolyrnerization of N,N-dimethyl acrylamide and N,N-bisacryl-diaminoethane and then functionalized with ethylenediamine after partial hydrolysis.Using solid-phase peptide synthesis with symmetrical anhydride of protected amino acid step by step,various peptide pendants were respectively anchored onto the functionalized carrier.The adsorption properties of these peptide-containing adsorbents for β-lactam antibiotics such as ampicillin and cefotaxime were then studied.The results showed that only those adsorbents in which peptide chains contained more than one lysine residues could obviously adsorb both β-lactams and that static interaction as well as hydrogen bond played an important role during the adsorption     

Proton Conductivity Improvement Effect of Cellulose on SPEEKK Based PEM

The proton exchange membranes(PEMs) were prepared through the solution mixing method of sulfonated poly(etlier ether ketone ketoneXsPEEKK) and cellulose. Cellulose was dissolved by 1-ally 1-3-methylimidazolium chioride(AMIMC1) and then mixed with sPEEKK solution. sPEEKK/cellulose(SC) composite membranes were prepared by solution casting. The membranes have high flexibility and transparency, which meant the compounding in molecular level. Meanwhile, the composite membranes showed excellent mechanical properties and high proton conductivity. The mechanical property reached 29 MPa, and the proton conductivity was as high as 0.32 S/cm. Thus, as a kind of biomaterials, cellulose could be ail excellent reinforcing material for poly(aryl ether ketone)(PAEK) based PEMs.     

Thermo-sensitive poly(DEGMMA-co-MEA) microgels: Synthesis,characterization and interfacial interaction with adsorbed protein layer

The novel microgels, poly[di(ethylene glycol) methyl ether methacrylate-co-2-methoxyethyl acrylate] poly(DEGMMA-co-MEA) microgels, were synthesized. The poly(DEGMMA-co-MEA) microgels were thermo-sensitive and exhibited a volume phase transitive temperature(VPTT) of 14–22 ?C. The incorporation of hydrophobic comonomer MEA shifted the VPTT of poly(DEGMMA-co-MEA) microgels to lower temperatures. The interfacial interaction of poly(DEGMMA-co-MEA) microgels and three model proteins, namely fibrinogen, bovine serum albumin and lysozyme, was investigated by quartz crystal microbalance(QCM). An injection sequence of "microgel-after-protein" was then established for the real-time study of the interaction of proteins and the microgels at their swollen and collapsed states by using QCM technique. The results indicated that the interfacial interaction of poly(DEGMMA-co-MEA) microgels and adsorbed protein layers was mainly determined by the electrostatic interaction. Because poly(DEGMMA-co-MEA) microgels were negatively charged in Tris-HCl buffer solution(p H = 7.4), the microgels did not adsorb on negatively charged fibrinogen and bovine serum albumin layers but strongly adsorbed on positively charged lysozyme layer. Stronger interaction between lysozyme and the microgels at collapsed state(i.e. at 37 ?C) was observed. Furthermore, the incorporation of MEA might weaken the interaction between poly(DEGMMA-co-MEA) microgels and proteins.