A new method for the preparation of fullerol

Reaction of C-60 with excessive potassium in toluene at refluxing temperature results in black precipitate KaC60 with high conversion, which can completely be hydrolyzed to prepare the fullerol. Investigations including FT-IR. H-1 NMR C-13 NMR, UV-Vis and FABMS of the product were reported.

Polymer-supported titanium catalysts for syndiotactic polymerization of styrene

Poly(styrene-co-acrylamide) (PSAm)-titanium complexes (PSAm . Ti) were prepared and characterized. It is found that the coordination number of acrylamide (Am) to Ti in the complexes is strongly dependent on Am content in PSAm, but not on [Am]/[Ti] ratio in the feed. The infrared and x-ray photoelectron spectra suggest that the polymer-supported complexes possess the structure [GRAPHICS] The catalytic behavior of the complexes in styrene polymerization is described. The catalytic activity is markedly affected by [Al]/[Ti] ratio in the complexes. C-13 NMR, IR, and DSC data indicate that the polystyrene obtained with PSAm . Ti/MAO (MAO = methylaluminoxane) is highly syndiotactic. Use of Et(3)Al and i-Bu(3)Al in place of MAO gives atactic polystyrene. The activities of the various aluminum compounds used as the cocatalysts decrease in the order: MAO > Et(3)Al > i-Bu(3)Al. The polymer-supported complexes show relatively high activity even after the complexes had been exposed to air for 19 h or higher polymerization temperature. (C) 1996 John Wiley & Sons, Inc.

Syntheses and crystal structures of [(C6H5CH2C5H4)(2)GdCl center dot THF](2) and (C6H5CH2C5H4)(2)ErCl center dot THF

[(C6H5CH2C5H4)(2)GdCl . THF](2) (1) and (C6H5CH2C5H4)(2)ErCl . THF (2) were prepared by the reaction of LnCl(3) (Ln=Gd, Er) with benzylcyclopentadienyl sodium in THF and characterized by elemental analysis, IR, H-1 NMR, C-13 NMR, MS and thermal gravimetry. The crystal structures of both compounds were determined. Complex 1 is dimeric and its structure belongs to the monoclinic, P2(1)/c space group with a=1.1432(2), b=1.2978(2), c=1.7604(3) nm, beta=108.75(2), V=2.4732(9) nm(3), Z=2(four monomers), D-c=1.54 g . cm(-3). R=0.0342 and R(w)=0.0362. Complex 2 is monomer and its structure belongs to the orthorhombic, P2(1)2(1)2(1) space group with a=0.8645(2), b=1.1394(3), c=2.5289(4) nm, V=2.4919(9) nm(3), Z=4, D-c=1.56 g . cm(-3). R=0.0514, R(w)=0.0529. The determination of the crystal structure shows that in complex 1 the benzyl groups on the cyclopentadienyls coordinated to Gd3+ are located in the opposite direction (139 degrees); in complex 2 the benzyl groups on the cyclopentadienyls coordinated to Er3+ are located in the same direction (6.5 degrees).

SYNTHESIS AND CHARACTERIZATION OF A NEW COMB-LIKE POLYMER-BASED ON POLY(VINYL METHYL ETHER-ALT-MALEIC ANHYDRIDE) BACKBONE

A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by LR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by C-13 NMR The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.

SYNTHESES AND CHARACTERIZATION OF [(MU-CF3CO2)(2)LN(MU-CF3CHO2)ALR(2)CENTER-DOT-2THF](2) AND THEIR CATALYTIC ACTIVITIES FOR POLYMERIZATION OF SOME POLAR MONOMERS

Three new bimetallic complexes were synthesized and crystalized by reactions of (CF3CO2)(3)Ln With R(1) AlR(2)(Ln=Nd and Y, R(1)=H, R=i-C4H9; Ln=Eu, R=R(1)=C2H5) in tetrahydrofuran solution, and their crystal structures were determined using a X-ray diffraction method. The structures and the questions on valence state and noncoplanarity in the structures were confirmed and cracked by means of H-1 NMR and C-13 NMR spectra, especially by C-13-H-1 COSY 2D NMR technique. A general formula of molecules of the three rare earth complexes was defined as follows: [(mu-CF3CO2)(2)Ln(mu-CF3CHO2)AlR(2) . 2THF](2) A mechanism on the formation of the new complexes was also proposed through the following five steps: alkylating, beta-elimination (or hydrogenation), hydrogen transfer, linkage and association. Both Y-Al and Eu-Al complexes function as a catalyst in polymerization of MMA and ECH. The polymer obtained from the first monomer is mainly syndiotactic chain structure and the polymerization of the last monomer shows higher catalytic activity. The Y-Al complex also capable of ring-opening polymerization of THF in case of adding-vary small amount of ECH and a oxonium ion mechanism of THF polymerization was suggested from the analysis of THF polymer terminal.

CURE AND IONIC-CONDUCTIVITY OF A 2-COMPONENT EPOXY NETWORK POLYMER ELECTROLYTE

In order to raise the room temperature ionic conductivity and improve the mechanical strength of a PEO-based polymer electrolyte, a non-crystalline two-component epoxy network was synthesized by curing diglycidyl ether of polyethylene glycol (DGEPEG) with triglycidyl ether of glycerol (TGEG) in the presence of LiClO4 salt, which acts in this system as both a ring opening catalyst and a source of ionic carrier. The structure of the precursors, the curing process and the cured films have been characterized by C-13 NMR, IR, DSC and ionic conductivity measurement techniques. The electrolyte system exhibits an ionic conductivity as high as similar to 10(-5) S/cm at 25 degrees C and is mechanically self-supportable. The dependence of ionic conductivity was investigated as a function of temperature, salt content, MW of PEG segment in DGEPEG and the proportion of DGEPEG in DGEPEG/TGEG ratio.

LOCAL MAIN-CHAIN DYNAMICS OF PHENOLPHTHALEIN POLYETHERSULFONE

Local main chain dynamics of dissolved phenolphthalein polyethersulfone (PES-C) in solution with chloroform-d(1) were examined through C-13 NMR relaxation measurements. Spin-lattice relaxation times and NOE (nuclear Overhauser effects) factors were measured as a function of temperature. The relaxation data were interpreted in terms of main chain segmental motion by using the damped orientational diffusion model (DAMP) and the conformation jump model (VJGM) derived by Valeur, Jarry, Geny, and Monnerie. The simulation method used is N-SIMPLEX, which gives, in this study, a result of the object function less than 10(-4). Correlation times were obtained for the main chain motion of PES-C with these models and the results indicate that the main chain of PES-C are flexible. The comparison between PES-C and 1,2-polybutadiene is proposed. The distribution of the correlation time for the main chain motion by using VJGM model is discussed. The temperature dependence of correlation times for PES-C indicating the dynamical rigidity of its chains is obtained.

Study on comblike polymer electrolyte

New comblike polymers(CP) have been synthesized by reacting monomethyl ether of polyethylene glycol(PEGME) with poly(methyl vinyl ether-alt-maleic anhydride)(MA) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification reaction in order to obtain a completely soluble product. They were characterized by IR, C-13 NMR and elemental analysis.

MOLECULAR CHARACTERISTICS AND CRYSTALLINE-STRUCTURE OF ETHYLENE-DIMETHYLAMINOETHYL-METHACRYLATE COPOLYMERS

The relationship between molecular and crystalline structural characteristics of the ethylene -dimethylaminoethylmethacrylate copolymers (EDAM) was investigated and related to melt flow index MI and average gross content of DAM comonomer, in comparison with low density polyethylene (LDPE) produced by the common high-pressure radical polymerization process. Although the average molecular weight and its distribution are influenced predominantly by the polymerization conditions, DAM-content seems not to depend significantly on molecular weight according to the GPC-FT/IR measurement. Comonomer sequence distributions were determined quantitatively with the C-13-NMR spectra entirely assigned by DEPT and H-1-C-13 COSY techniques. The result suggests the alternating copolymerization tendency and surprisingly coincides with the simulation out-puts based on the assumption of continuous complete mixing reactor model, using Mayo-Lewis equation and the same Q-e values as previously reported on different types of copolymers such as EVA and St.DAM (VA;vinylacetate, St;styrene). It was confirmed by WAXD and SAXS analyses that the crystallinity X(c) and the thickness of lamellar crystal l(c) decreased with increasing DAM-content, whereas the a-lattice and b-lattice dimensions enlarged. X(c) and l(c) can definitely be correlated to the heats of fusion and crystallization measured by DSC. The average size of spherulites measured with light scattering photometry tends to be enlarged with decreasing molecular weight (increasing MI) and DAM-content.

STRUCTURES AND PROPERTIES OF DIALKYL FUMARATES POLYMERS

Polymers of methyl-iso-propyl fumarate, di-iso-propyl fumarate, di-t-butyl fumarate, di-s-butyl fumarate, di-s-amyl fumarate and di-cyclo-hexyl fumarate were prepared by radical polymerization. The structures of the polymers were examined by H-1-NMR, C-13-NMR and WAXD. Some properties of the polymers, including thermal properties, were examined.

UNSTEADY DIFFUSION KINETICS OF ZIEGLER-NATTA HETEROGENEOUS CATALYST POLYMERIZATION .4. PREDICTION OF EXPERIMENTAL RESULTS OF PROPYLENE ETHYLENE 1-HEXADECENE TERPOLYMERIZATION

The prediction, based on unsteady diffusion kinetics, of the enhancement of reactivity and incorporation of 1-hexadecene in its copolymerization with propylene on adding a small amount of ethylene (increase from 5,2 mol-% to 10,8 mol-% when 2% of ethylene was added, and to 16,1 mol-% when 5% was added) was verified in the terpolymerization of propylene/1-hexadecene/ethylene on a commercial Solvay-type delta-TiCl3 catalyst. The catalyst efficiency was thus also increased. These augmentations originate from the increase in diffusion coefficient of 1-hexadecene at the catalyst surface when the PP crystallinity decreases on introduction of ethylene. Calculation based on unsteady diffusion kinetics showed that the order of diffusion coefficients ethylene > propylene > 1-hexadecene is reversed as the monomer concentration increases when the monomers are not at their equilibrium concentration. Sequence distribution as determined by means of C-13 NMR revealed a tendency of blocky structure rather than a Bernoullian one. The terpolymer compositions obtained by means of an IR method developed in this work conform rather well with the NMR results. Results in this work not only support the unsteady diffusion kinetics but also provide a new route to prepare olefinic copolymer rubbers with heterogeneous titanium catalysts.

SYNTHESIS AND CHARACTERIZATION OF POLY-ORTHO-METHYLANILINE WITH DIFFERENT DEGREES OF OXIDATION

Poly-ortho-methylanilines (POT) in three states fully oxidized, fully reduced and oxidized in varying degrees were synthesized by the reaction of common POT (C-POT) having nearly equal amounts of benzenediamine and quinonediimine units with iodine or phenyl-hydrazine, and the resulting polymers were characterized by IR, C-13-NMR, SEM and elemental analysis. The results showed that the quinonediimine unit in C-POT could be reduced by phenylhydrazine to the benzenediamine unit, forming the polymer with low OD (oxidation degree) or in a fully reduced state and that iodine-oxidation resulted in the increase of quinonediimine unit and decrease of benzenediamine unit. The solubility and flexibility of the formed polymers depend strongly on the amount of quinonediimine unit in it. It is necessary to reduce the content of quinonediimine structure unit in order to improve the solubility of aniline-class polymers.

STRUCTURE INVESTIGATION OF TI(OBU)4-ALET3 CATALYST BEFORE AND AFTER HEAT-TREATMENT

The catalyst structure of Ti(OBu)4-AlEt3 at different Al/Ti ratios before and after heat aging has been investigated from the data of UV, GC-MS, ESR and C-13 NMR spectra. The complex compounds formed by HTiEt2 and AlEt2(OBu) exist mainly in the catalyst solution, and no -OBu ligands linking with Ti atoms can be found at an Al/Ti ratio of four before heat aging. Many kinds of catalytic species with different size are formed after heat aging the catalyst at 110-degrees-C for 2 h. Dehydrogenation, accompanied by the valence change from Ti3+ to Ti2+, is observed during the aging process of the catalyst.

CHARACTERIZATION, MORPHOLOGY AND THERMAL-PROPERTIES OF ETHYLENE PROPYLENE BLOCK COPOLYMERS

Characterization, morphology and thermal properties of commercial ethylene-propylene block copolymers have been studied by C-13 nuclear magnetic resonance (n.m.r.) spectroscopy, differential scanning calorimetry (d.s.c.), dynamic mechanical analysis (d.m.a.) and scanning electron microscopy (SEM). The results obtained show that there exists some ethylene-propylene random copolymer in the block copolymers extractable by n-heptane. The possibility of forming PP-b-PE diblock copolymer is questionable on the basis of the effects of residual propene and the chain-transfer reaction in the sequential copolymerization. A difference in the thermal properties between commercial ethylene-propylene block copolymers and PP/PE blends was noticed, which cannot be used to identify PP-b-PE diblock copolymer. The multiphase structure has been confirmed by d.m.a. and SEM, with ethylene-propylene random copolymer and polyethylene forming the domains in the matrix of polypropylene.

An acidic polysaccharide with xylose branches from Porphyra yezoensis

An acidic polysaccharide (PY3) was isolated from the hot water extract of the red algae Porphyra yezoensis by successive column chromatographies over DEAE-cellulose and Sephadex G-200. PY3 with an average molecular weight of 1.8x10(5) was demonstrated to be composed of galactose (Gal), 3,6-anhydrogalactose (3,6-AnGal), 6-OSO3-galactose (6-OSO3-Gal) and xylose (Xyl) in an approximate molar ratio of 25 : 15, 10, 1. In view of Smith degradation and methylation and on the basis of spectral evidence including those of IR, GC, GC-MS, and H-1 and C-13 NMR, the most probable repeating unit of PY3 could be proposed as [(1-->3)beta -D-Gal(1 --> 4)alpha -L-3,6-AnGal](3)-[(1 --> 3)beta -D-Gal(1 --> 4)alpha -L-6-OSO3-Gal](2) with a xylose moiety at the C-6 of one of every twenty-five beta -D-Gal residues. To our knowledge, PY3 was shown to be the first porphyran possessing occasional xylose branches.