Aliphatic Poly(ester-carbonate)s Bearing Amino Groups and Its RGD Peptide Grafting

This article deals with (1) synthesis of novel cyclic carbonate monomer (2-oxo [1,3]dioxan-5-yl)carbamic acid benzyl ester (CAB) containing protected amino groups; (2) ring-opening copolymerization of the cyclic monomer with L-lactide (LA) to provide novel degradable poly(ester-carbonate)s with functional groups; (3) removal of the protective benzyloxycarbonyl (Cbz) groups by catalytic hydrogenation to afford the corresponding poly(ester-co-carbonate)s with free amino groups; (4) grafting of oligopeptide Gly-Arg-Gly-Asp-Ser-Tyr (GRGDSY, abbreviated as RGD) onto the copolymer pendant amino groups in the presence of 1,1'-carbonyldiimidazole (CDI).

Synthesis and characterisation of novel functional polyolefin containing sulfonic acid groups

The strong polar group, sulfonic acid, has successfully been introduced into ethylene/allylbenzene copolymers without degradation or crosslinking via chlorosulfonation reaction with chlorosulfonic acid as a chlorosulforiating agent in 1, 1,2,2-tetrachloroethane followed by hydrolysis. The degree of sulforiation (DS) can be easily controlled by changing the ratio of chlorosulfonic acid to the pendant phenyls of the copolymer. The microstructure of sulfonated copolymers were unambiguously revealed by H-1 NMR and H-1-H-1 COSY spectral analyses, which indicates that all the sulforiation reactions exclusively took place at the para-position of the aromatic rings.

Branched polystyrene with abundant pendant vinyl functional groups from asymmetric divinyl monomer

Branched polystyrenes with abundant pendant vinyl functional groups were prepared via radical polymerization of an asymmetric divinyl monomer, which possesses a higher reactive styryl and a lower reactive butenyl. Employing a fast reversible addition fragmentation chain transfer (RAFT) equilibrium, the concentration of active propagation chains remained at a low value and thus crosslinking did not occur until a high level of monomer conversion. The combination of a higher reaction temperature (120 degrees C) and RAFT agent cumyl dithiobenzoate was demonstrated to be optimal for providing both a more highly branched architecture and a higher polymer yield.

Synthesis and characterization of titanium complexes bearing two beta-enaminoketonato ligands with electron-withdrawing groups and their behavior in ethylene polymerization

A series of new titanium complexes with two asymmetric bidentate beta-enaminoketonato (N,O) ligands (4b-t), [RN=CCF3)CHC(t-BU)O](2)TiCl2 (4b, R = -C6H4F(o); 4c, R = -C6H4F(m);4d, R = -C6H4F(p); 4e, R = - C6H3F2(2,3); 4f, R = -C6H3F2(2,4); 4g, R = -C6H3F2(2,5); 4h, R = -C6H3F2(2,6); 4i, R = -C6H3F2(3,4); 4j, R = -C6H3F2(3,5); 4k, R = -C6H2F3(2,3,4); 4l, R = -C6H2F3(3,4,5); 4m, R = -C6H4CF3(o); 4n, R =-C6H4CF3(m); 4o, R = -C6H4CF3(p); 4p, R = -C6H4Cl(p); 4q, R = -C6H4I(p); 4r, R = -C6H4NO2(P); 4s, R = -CH2C6H5; 4t, R = -C6H11), have been synthesized and characterized.

Naphthalene-Based Poly(arylene ether ketone) Copolymers Containing Sulfobutyl Pendant Groups for Proton Exchange Membranes

A new monomer 1,5-bis(4-fluorobenzoyl)-2,6-dimethoxynaphthalene (DMNF) was prepared and further polymerized to form naphthalene-based poly(arylene ether ketone) copolymers containing methoxy groups (MNPAEKs). The side-chain-type sulfortated naphthalene-based poly(arylene ether ketone) copolymers (SNPAEKs) were obtained by demethylation and sulfobutylation. Flexible and tough membranes with reasonably high mechanical strength were prepared. The SNPAEKs membrane showed anisotropic membrane swelling with larger swelling in thickness than in plane. Transmission electron microscopy (TEM) analysis revealed clear nano-phase separated structure of SNPAEKs membranes, which composed of hydrophilic side chain and hydrophobic main-chain domains.

Effect of hydroxyl and amino groups on electrochemiluminescence activity of tertiary amines at low tris(2,2 '-bipyridyl)ruthenium(II) concentrations

ECL of several amines containing different numbers of hydroxyl and amino groups was investigated. N-butyldiethanolamine is found to be more effective than 2-(dibutylamino)ethanol at gold and platinum electrodes, and is the most effective coreactant reported until now. Surprisingly, ECL intensities of monoamines, such as 2-(dibutylamino)ethanol and N-butyldiethanolamine, are much stronger than that of diamines including N,N,N',N'-tetrakis-(2-hydroxyethyl)-ethylenediamine and N,N,N',N'-tetrakis-(2-hydroxypropyl)ethlenediamine. The striking contrast between ECL signals of the investigated monoamines and diamines may result from more significant side reactions of diamines, such as the intramolecular side reactions between oxidative amine cation radicals and reductive amine free radicals.

Synthesis of Soluble Poly(arylene ether sulfone) Ionomers with Pendant Quaternary Ammonium Groups for Anion Exchange Membranes

A new bisphenol monomer, 2,2'-dimethylaminemetllylene-4,4'-biphenol (DABP), was easily prepared by Mannich reaction of dimethylamine and formaldehyde with 4,4'-biphenol. Novel partially fluorinated poly(arylene ether sulfone)s with pendant quaternary ammonium groups were prepared by copolymerization of DABP, 4,4'-biphenol, and 3,3',4,4'- tetrafluorodiphenylsulfone, followed by reaction with iodomethane. The resulting copolymers PSQNI-x (where x represents the molar fraction of DABP in the feed) with high molecular weight exhibited outstanding solubility in polar aprotic solvents; thus, the flexible and tough membranes of PSQNI-x with varying ionic content could be prepared by casting from the DMAc solution. Novel anion exchange membranes, PSQNOH-x, were obtained by an anion exchange of PSQNI-x with 1 N NaOH.

Novel sulfonated poly(arylene ether ketone) copolymers bearing carboxylic or benzimidazole pendant groups for proton exchange membranes

A novel strategy in which the benzimidazole group and sulfonic group are simultaneously attached to an aromatic polymer has been reported in this paper. For this purpose, sulfonated poly(arylene ether ketone) copolymers containing carboxylic acid groups (SPAEK-x-COOH, x refers to the molar percentage Of sulfonated repeating units) are prepared by the aromatic nucleophilic polycondensation of sodium 5,5'-carbonyl-bis(2-fluobenzene-sulfonate) (SDFBP), 4,4'-difluorobenzophenone (DFBP) and phenolphthalin (PPL). Then the carboxylic acid groups attached to the SPAEK-x-COOH are transformed to benzimidazole units through condensation reactions (referred to as SPAEK-x-BI). Fourier transform infrared spectroscopy and H-1 NMR measurements are used to characterize and confirm the structures of these copolymers.

Synthesis and characterization of novel sulfonated poly(arylene ether ketone) copolymers with pendant carboxylic acid groups for proton exchange membranes

A series of novel side-chain-type sulfonated poly(arylene ether ketone)s with pendant carboxylic acid groups copolymers (C-SPAEKs) were synthesized by direct copolymerization of sodium 5,5'-carbonyl-bis(2-fluorobenzenesulfonate), 4,4'-difluorobenzophenone and 4,4'-bis(4-hydroxyphenyl) valeric acid (DPA). The expected structure of the sulfonated copolymers was confirmed by FT-IR and H-1 NMR. Membranes with good thermal and mechanical stability could be obtained by solvent cast process. It should be noted that the proton conductivity of these copolymers with high sulfonation degree (DS > 0.6) was higher than 0.03 S cm(-1) and increased with increasing temperature. At 80 degrees C, the conductivity of C-SPAEK-3 (DS = 0.6) and C-SPAEK-4 (DS = 0.8) reached up to 0.12 and 0.16 S cm-1, respectively, which were higher than that of Nafion 117 (0.10 S cm(-1)).

Super-hydrophobicity of silica nanoparticles modified with vinyl groups

Super-hydrophobic films with vinyl-modified silica nanoparticles (V-SiOx-NPs) were successfully prepared. The rough surface, which was composed of microstructures of disordered V-SiOx-NPs and nanostructures on the surface of V-SiOx-NPs, rather than the chemical composition devoted to the super-hydrophobicity of film. The relationship between contact angle and diameter of V-SiOx-NPs was then investigated. The sessile contact angles (CA) of films with 150-1600nm V-SiOx-NPs were around 166 regardless the diameter, while the film with 85 nm V-SiOx-NPs had the lowest CA of about 158. The packing manner of V-SiOx-NPs determined the air fraction on the surface and then the CA.

Effects of polymerization conditions on hydrophilic groups in aromatic polyamide thin films

For polyamide used in reverse osmosis (RO) membranes, the content of pendant acid groups is critical to its performance. In this work, FTIR was used to analyze the acid contents in the polyamide films prepared via interfacial polymerization of trimesic acid trichloride (TMC) in hexane and 1,3-phenylenediamine (MPDA) in water, and the effects of reaction conditions, including monomer concentrations, time, and temperature, were studied. It was found that more pendant acid groups are present in the polyramide film at higher TMC concentrations or lower MPDA concentrations, and longer reaction times and lower temperatures also favor the formation of the free acids. These results can be explained by the monomer diffusion in the interfacial polymerization process. This work may help the design and fabrication of RO membranes with different hydrophilicity and target performance.

Naphthyl and thionaphthyl end-capped oligothiophenes as organic semiconductors: Effect of chain length and end-capping groups

Two series of oligothiophenes (OThs), NaTn and TNTn (n = 2-6 represents the number of thiophene rings), end-capped with naphthyl and thionaphthyl units have been synthesized by means of Stille coupling. Their thermal properties, optical properties, single crystal structures, and organic field-effect transistor performance have been characterized. All oligomers display great thermal stability and crystallinity. ne crystallographic structures of NaT2, NaT3, TNT2, and TNT3 have been determined. The crystals of NaT2 and NaT3 are monoclinic with space group P2(1)/C, while those of TNT2 and TNT3 are triclinic and orthorhombic with space groups P-1(-) and P2(1)2(1)2(1), respectively. All oligomers adopt the well-known herringbone packing-mode in crystals with packing parameters dependent on the structure of the end-capping units and the number of thiophene rings. The shorter intermolecular distance in NaT3 compared to NaT2 indicates that the intermolecular interaction principally increases with increasing molecular length. X-ray diffraction and atomic force microscopy (AFM) characterization indicate that the NaTn oligomers can form films with better morphology and high molecular order than TNTn oligomers with the same number of thiophene rings. The NaTn oligomers exhibit mobilities that are much higher than those for TNTn oligomers (0.028-0.39 cm(2) V-1 s(-1) versus 0.010-0.055 cm(2) V-1 s(-1), respectively).

Synthesis and characterization of rigid-rod sulfonated polyimides bearing sulfobenzoyl side groups as proton exchange membranes

A novel wholly aromatic diamine, 2,2 '-bis(3-sulfobenzoyl)benzidine (2,2 '-BSBB), was successfully prepared by the reaction of 2,2 '-dibenzoylbenzidine (2,2 '-DBB) with fuming sulfuric acid. Copolymerization of 1,4,5,8-naphathlenetetracarboxylic dianhydride with 2,2 '-BSBB and 2,2 '-DBB generated a series of rigid-rod sulfonated polyimides. The synthesized copolymers with the -SO3H group on the side chain of polymers possessed high molecular weights revealed by their high viscosity and the formation of tough and flexible membranes. The copolymer membranes exhibited excellent oxidative stability and mechanical properties due to their fully aromatic structure extending through the backbone and pendent groups. They displayed clear anisotropic membrane swelling in water with negligibly small dimensional changes in the plane direction of the membrane. The proton conductivities of copolymer membranes increased with increasing IEC and temperature, reaching value above 1.25 x 10(-1) S/cm at 20 degrees C, which is higher than that of Nafion (R) 117 at the same measurement condition. They displayed reasonably high proton conductivity due to the higher acidity of benzoyl sulfonic acid group, the larger interchain spacing, which is available for water to occupy, taking their lower water uptake (WU) into account. Consequently, these materials proved to be promising as proton exchange membrane.

Sulfonated polyimides bearing benzimidazole groups for proton exchange membranes

A series of sulfonated polymides containing benzimidazole groups were synthesized using 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BTDA), 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid (ODADS) as the sulfonated diamine, and 2-(3',5-diaminophenyl)benzimidazole (a) or 6,4'-diamino-2-phenylbenzimidazole (b) as the nonsulfortated diamine. The electrolyte properties of the synthesized polyimides Ia-x, Ib-x, x refers to molar percentage of the sulfonated diamine) were investigated and compared with those of polyimides (Ic-x) from BTDA, ODADS, and m-phenylenediamine (c). All synthesized polyimides possessed high molecular weights revealed by their high viscosity, and formation of tough and flexible membranes. Polyintides with benzimidazole groups exhibited much better swelling capacity than those without benzimiclazole groups. This was attributed to the strong interchain interaction through basic benzimidazole functions and sulfonic acid groups. The sulfortated polyimides that are incorporated with 1, 1',8,8'-binaphthalimide exhibited better hydrolytic stability than that with 1,4,5,8-naphthalimide. Polyimide membranes with good water stability as well as high proton conductivity were developed. Polyimide membrane (Ia - 90), for example, did not lose mechanical properties after being soaked in boiling water for tOOO h, while its proton conductivity was still at a high level (compared to that of Nafion 117).

Synthesis, properties, and gas permeation performance of cardo poly(arylene ether sulfone)s containing phthalimide side groups

Novel bisphenol monomers (1a-d) containing phthalimide groups were synthesized by the reaction of phenolphthalein with ammonia, methylamine, aniline, and 4-tert-butylanilne, respectively. A series of cardo poly (arylene ether sulfone)s was synthesized via aromatic nucleophilic substitution of 1a-d with dichlorodiphenylsulfone, and characterized in terms of thermal, mechanical and gas transport properties to H-2, O-2, N-2, and CO2. The polymers showed high glass transition temperature in the range 230-296 degrees C, good solubility in polar solvents as well as excellent thermal stability with 5% weight loss above 410 degrees C. The most permeable membrane studied showed permeability coefficients of 1.78 barrers to O-2 and 13.80 barrers to CO2, with ideal selectivity. factors of 4.24 for O-2/N-2 pair and 28.75 for CO2/CH4 pair. Furthermore, the structure-property relationship among these cardo poly(arylene ether sulfone)s had been discussed on solubility, thermal stability, mechanical, and gas permeation properties. The results indicated that introducing 4-tert-butylphenyl group improved the gas permeability of polymers evidently.