X-ray crystallographic structure of cyclic tetramer ester based on bisphenol-A and o-phthaloyldichloride

The polycrystalline powder of the cyclic tetramer ester based on bisphenol-A and o-phthaloyldichloride has been prepared by recrystallization from nitrobenzene and its crystal structure determined by wide-angle X-ray diffraction. The unit cell is orthorhombic and has dimensions a=0.967 nm, b=0.8699 nm, c = 2.0859 nm. With two tetramers per unit cell, the crystal density is 1.36 g cm(-3). Indices of crystal diffraction peaks are also detailed in the present work. Copyright (C) 1996 Elsevier Science Ltd.

Effect of structures of modifiers on electrochemistry of di-mu-oxo dimanganese 2,2'-bipyridine complex

The gold electrodes modified with 2-picolinic acid , nicotinic acid, iso-nicotinic or thiophene were prepared using membrane transfer method, The electrochemistry of di-mu-oxodimanganese 2,2'-bipyridine complex was studied in the acetic acid buffer solution at different modified gold electrodes, It was found that the modifiers which can promote the electrochemical reaction of the complex should be of at least two functional groups, One group can be bound to the electrode surface and the other can form electron transfer pathway between the modifier and the complex through sal; bridge or hydrogen bond, In addition, the mechanism of the electrochemical reaction was discussed.

Comparative study on polyimides from 3,3'- and 4,4'-linked diphthalic anhydride

1,4-Bis(2,3-dicarboxyphenoxy)benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy)benzene dianhydride, bis(2,3-dicarboxyphenoxy) sulfide dianhydride, bis (3,4-dicarboxyphenoxy)sulfide dianhydride, and 2,3,3',4'-tetracarboxy diphenyl sulfide dianhydride were synthesized from 3-chlorophthalic anhydride and 4-chlorophthalic anhydride. Bis(2,3-dicarboxyphenyl)sulfone and bis(3,4-dicarboxyphenyl) sulfone were obtained by the oxidation of the corresponding bis(dicarboxyphenyl)sulfide by hydrogen peroxide. The polyimides from the dianhydrides mentioned above and 4,4'-oxydianiline were prepared. The properties, such as dynamic mechanical behavior, thermooxidative stability, stress-strain behavior, chemical resistance, and permeability to some gases have been in investigated for the isomeric polyimides. (C) 1996 John Wiley & Sons, Inc.

SYNTHESIS AND ORIENTATION OF MELAMINEALDEHYDE RESIN CROSS-LINKED POLYMERS

Three kinds of hydroxy-terminated oligomers were synthesized and characterized by IR, DSC and GPC. The oligomers were crosslinked by melaminealdehyde resin. The orientation and relaxation of the poled and crosslinked polymers were studied by UV-Vis spectra. It was shown that polymers had high orientational stability after corona-poling and crosslinking.

GAS PERMEABILITIES AND PERMSELECTIVITY OF PHOTOCHEMICALLY CROSS-LINKED POLYIMIDES

Photosensitive polyimide BTDA-3MPDA was modified by UV irradiation. The structure of UV-irradiated polyimides was investigated by FTIR and gel fraction measurements. The results showed that longer UV exposure time resulted in a higher extent of crosslinking. The gas permeabilities of hydrogen, oxygen and nitrogen through UV-irradiated polyimides were characterized in a temperature range from 30 degrees C to 90 degrees C. Photocrosslinking resulted in a sharp decline in gas permeability for hydrogen, oxygen, and nitrogen through polyimide in the initial stage of photocrosslinking. Then, as the crosslinked benzophenone percentage amounted to 28-38% for hydrogen, 17-31% for oxygen and 3-28% for nitrogen, the gas permeabilities showed another sharp decline. Gas permselectivity increased significantly with the progress of photocrosslinking, and it can be adjusted in a wide range by controlling the extent of crosslinking. Arrhenius plots of gas permeability for hydrogen and oxygen through UV-irradiated polyimides are straight lines; for nitrogen, however, change in the slope of the straight line is observed and activation energies for hydrogen and oxygen permeation show abrupt increases when crosslinked benzophenone percentage amounts to about 30%. UV-irradiated polyimides with simultaneous high gas permeability and permselectivity make them ideal candidate materials for gas separation. (C) 1995 John Wiley & Sons, Inc.

SYNTHESIS OF CROSS-LINKED 2ND-ORDER NONLINEAR-OPTICAL POLYMERS WITH HIGH T-G

Synthesis and characterization of a diamino dihydroxyl azo compound were reported, The crosslinking reaction process of the diamino dihydroxyl azo compound with the biuret of hexamethylene diisocyanate was studied by FTIR, The glass transition temperatures of crosslinked polymers were measured by DSC, The orientation and oriented stability of crosslinked and poled polymers were studied by UV-Vis spectra.

POLYMERIZATION OF ACRYLONITRILE INITIATED BY DI(2,6-DI-TERT-BUTYL-4-METHYLPHENOXO) SAMARIUM COMPLEX

The polymerization of acrylonitrile initiated by organolanthanide complexes alone is studied for the first time. The effect df polymerization conditions on catalytic activity of the title complex and molecular weight of the polymers produced have been studied.

SYNTHESIS AND CHARACTERIZATION OF CROSS-LINKED 2ND-ORDER NONLINEAR-OPTICAL POLYMER

The present paper reports the synthesis of glycidyl monoether of 4-[(p-nitrophenyl) azo] phenol (GMNA) and crosslinking reaction of GMNA with hexamethylene diisocyanate biuret (HDIB). The Tg of crosslinked polymer was investigated by DSC. The orientation and stability of the poled and crosslinked polymer film were studied by UV-Vis spectra and Maker fringe method.

GAMMA-RADIATION INDUCED CROSS-LINKED PEO-LICLO4 SOLID-ELECTROLYTE SYSTEM

Aimed at raising the room temperature ionic conductivity of PEO-based solid polymer electrolyte and considered that the ionic conduction preferentially occurs in the amorphous phase, we lightly crosslinked the high MW PEO through gamma-irradiation and further suppressed the residual crystallinity by plasticizing with propylene carbonate. By incorporating LiClO4 salt to the above described polymer host, the ambient (25 degrees C) ionic conductivity of the electrolyte system could reach as high as 6.8 X 10(-4) S/cm. As the electrolyte was a crosslinked system, it was mechanically self-supportable. Based on the preliminary results of the electrochemical performance of the secondary lithium battery, assembled by using this kind of solid electrolyte and polyaniline as positive electrode, it is realized that the electrolyte thus prepared is of high expectancy.

A BIS(2,6-DI-TERT-BUTYL-4-METHYLPHENOLATO)-SAMARIUM(II) COMPLEX, [SM(OAR)2(THF)3]-THF

The title complex, bis(2,6-di-tert-butyl-4-methyl-phenolato-O)tris(tetrahydrofuran-O)samarium tetrahydrofuran solvate, [Sm(C15H23O)2(C4H8O)3].C4H8O, has distorted trigonal bipyramidal geometry around the Sm(II) atom. The 0(2), 0(3) and 0(4) atoms of the

STRUCTURE AND PROPERTIES OF AB CROSS-LINKED POLYMERS

Hydroxy-terminated oligomers, such as polyester, polyether, or castor oil, were reacted with toluene diisocyanate to form isocyanate-terminated prepolymers, which were then reacted with 2-hydroxyethyl acrylate to obtain vinyl-terminated prepolymer (VTP).

CYCLIC VOLTAMMETRIC STUDY OF QUININE DERIVATIVES TRANSFER ACROSS THE WATER NITROBENZENE INTERFACE

Quinine derivatives, quinine hydrochloride and 8-hydroxyquinoline, transfer across the water/nitrobenzene interface was studied by cyclic voltammetry. The effect of solution acidity on the transfer behaviour was observed. Transfer mechanism was discussed

SYNTHESIS AND MOLECULAR-STRUCTURE OF NBU2[(MEO)3C6H2C(O)N2CHC6H4O]SN FORMED IN THE REACTION OF DI-N-BUTYLTIN(IV) OXIDE WITH 3,4,5-TRIMETHOXY-BENZOYL SALICYLAHYDRAZONE

The title complex was synthesized and characterized by H-1, C-13, Sn-119 NMR and IR spectra. A single crystal X-ray diffraction study confirmed its molecular structure and revealed that 3,4,5-trimethoxy-benzoyl salicylahydrazone was a tridentate and approximately planar ligand. The complex crystallizes in the triclinic space group P1BAR with a = 9.208(3), b = 12.536(2), c = 12.187(4) angstrom, alpha = 113.12(2), beta = 90.58(2), gamma = 81.42(2), V = 1277.5(6) angstrom, Z = 2. The structure was refined to R = 0.033 and R(w) = 0.041 for 3944 observed independent reflections. The tin atom has a distorted trigonal bipyramidal coordination. The Sn-C bond lengths are 2.129(5) and 2.113(5) angstrom (av. 2.121(5) angstrom), the C-Sn-C angle is 123.3(2); the bond length between the tin atom and the chelating nitrogen is 2.173(3) angstrom. Two chain carbon atoms and the chelating nitrogen atom occupy the basal plane. The skeleton of two erect oxygen atoms and the tin atom is bent (O-Sn-O angle = 153.5(1)). In the complex, the ligand exists in the enol-form.

EFFECTS OF DOPANT AND SOLVENT ON THE PROPERTIES OF POLYPYRROLE - INVESTIGATIONS WITH CYCLIC VOLTAMMETRY AND ELECTROCHEMICALLY INSITU CONDUCTIVITY

A new method for electrochemically in situ conductivity measurements based on a reusable glassy carbon disc carbon fibre array double electrode is described. Using this technique and cyclic voltammetry, we have investigated the effects of the doping anion and solvent on the electrochemical properties of polypyrrole film. The electroactivity and potential dependent conductivity of polypyrrole film are strongly affected by solvent and the doping anion's solubility in the solvent, and also by the history of electrochemical treatments in different electrolyte solutions. It is very interesting that NO3-doped polypyrrole can completely keep its conducting state (doped state) at a reasonably negative potential (eg -0.8 V vs. sce) in acetonitrile solutions.