bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photocrosslinkable polymers for membranes: polyamides from N‐cinnamoyl‐5‐aminoisophthalic acid and aromatic diamines
Authors: Ommer Harald J. , Ritter Helmut 
Published: April 2003

AbstractN‐Cinnamoyl‐5‐aminoisophthalic acid was synthesized by acylation of 5‐aminoisophthalic acid with cinnamoyl chloride in N,N‐dimethylacetamide (DMAc) solution. The direct polycondensation of the new diacid with various aromatic diamines results in a new type of photoreactive aromatic polyamides with inherent viscosities of 0,4–1,7 dL/g. The preparation of homogeneous and asymmetric photocrosslinkable membranes from N‐methyl‐2‐pyrrolidone (NMP) solution was performed. The mechanical stability of a film was improved by UV irradiation while the permselectivities of ethanol/water and (tert‐butyl methyl ether)/methanol mixtures were not influenced by the photochemical crosslinking.
Preparation and characterization of fluorine‐containing aromatic condensation polymers, 3. Preparation and characterization of fluorine‐containing aromatic poly(ketone)s and copoly(ketone)s by direct polycondensation of 4,4′‐[1‐(trifluoromethyl)trifluoroethylidene]dibenzoic acid and/or 4,4′ ‐isopropylidenedibenzoic acid with diaryl compounds
Authors: Saegusa Yasuo , Kojima Akihiro , Nakamura Shigeo 
Published: April 2003

AbstractFour types of fluorine‐containing aromatic poly(ketone)s, poly(ether/ketone), poly(ketone), poly(sulfide/ketone) and poly(sulfone/ketone), were synthesized from 4,4′‐[1‐(trifluoromethyl)‐trifluoroethylidene]dibenzoic acid and diaryl compounds, diphenyl ether, diphenyl ketone, diphenyl sulfide and diphenyl sulfone, by direct polycondensation using phosphorus pentoxide/methanesulfonic acid as both condensing agent and solvent. The expected chemical structures were confirmed by IR and 1H NMR spectroscopy and elemental analysis. Two series of fluorine‐containing copoly(ketone)s, copoly(ether/ketone) and copoly(sulfide/ketone), were also similarly prepared by using different proportions of the dicarboxylic acid and the corresponding analogous 4,4′‐isopropylidenedibenzoic acid but without fluorine, and the effect of the introduction of the fluorine atom on the properties of these polymers was discussed with relation to the fluorine contents. Most of the poly(ketone)s with and without fluorine were essentially amorphous and soluble in a wide range of organic solvents including chloroform and tetrahydrofuran, and afforded transparent films by solution casting. The contact angles of the films to water increased significantly and monotonously with increasing fluorine content in the copoly(ketone)s. Thermal properties such as glass transition temperature and thermal stability were also successfully improved by the introduction of a fluorine atom, and both of them increased markedly and monotonically with the increase of the fluorine content.
Alkoxy‐substituted liquid‐crystalline aromatic copolyesters, 2
Authors: Schleeh Thomas , Roetting Oliver , Bettge Dirk , Hinrichsen Georg , Koßmehl Gerhard 
Published: April 2003

AbstractNumber‐average molecular weights, Mn, up to 25 000, and inherent viscosities, ηinh, up to 2,88 dL/g, were found for the soluble members of an alkoxy‐substituted copolyester series (HTO5‐X series). A liquid‐crystalline (high‐temperature) phase was distinguished by IR and wide‐angle X‐ray scattering on molten and quenched samples in form of a nematic sanidic phase. In this phase no relationship exists between the orientation of the aromatic polyester backbone and that of the laterally attached alkoxy groups. Further, it was proven by IR that only the polyester backbone can be aligned by shear stress. If the applied shear stress is very strong, the orientation of the stiff backbone becomes sensitive to disturbances caused by mechanical forces.
Preparation and characterization of polyurethane‐type macroazo initiators for block copolymerization
Authors: Kinoshita Hiroshi , Tanaka Nobuo , Araki Takeo , Syoji Akio , Ooka Masataka 
Published: April 2003

AbstractThe use of dipropylene glycol in the polyaddition of 2,2′‐azobis(2‐cyanopropanol) (ACP) with hexamethylene diisocyanate results in soluble polyurethane‐type macroazo initiators (PUMAI) in high yields. By adjusting the amount of ACP used, the number‐average molecular weight of the polyurethane segments was adjusted in the range from 2000 to 6000 at an azo content in the PUMAI's of 0,18 to 0,5 mmol/g‐polymer (determined by UV). 13C NMR spectroscopy of the PUMAI's showed that no significant decomposition of azo groups occurred during polyaddition. At 80°C the PUMAI's initiated effectively the radical solution polymerization of vinyl monomers. As supposed from extraction results and the polymerization mechanism, block copolymers are formed. The whole process seems to be adequate for industrial applications.
Segmental mobility of model compounds for rubber reinforcement
Authors: Hommel Hubert , Touhami Ahmed , Legrand André Pierre , Balard Henri , Papirer Eugène 
Published: April 2003

AbstractThe motion of spin‐labeled poly(ethylene oxide) (PEO) grafted on a silica surface in contact with various dense media was studied by electron paramagnetic resonance spectroscopy. Grafted molecules of molecular weight 2000, with grafting ratios of 0,045, 0,057, 0,126 and 0,42 molecules/nm2 have conformations ranging from the single coil regime to the brush regime. A comparison is made between samples prepared by adding the melt of PEO to the grafted silica, and others prepared by adding model compounds of rubber, namely squalane and squaleneSqualane: system. name: 2,6,10,15,19,23‐hexamethyltetracosane.Squalene: system. name: 2,6,10,15,19,23‐hexamethyl‐2,6,10,14,18,22‐tetracosahexaene.
. The local elementary mobilities of the loops and tails of PEO are shown to be affected by all these factors.
Behaviour of permeation and separation for aqueous organic acid solutions through poly(vinyl chloride) and poly[(vinyl chloride)‐co‐(vinyl acetate)] membranes
Authors: Okuno Hiroshi , Nishimoto Hiroaki , Miyata Takashi , Uragami Tadashi 
Published: April 2003

AbstractThe permeation and separation characteristics of poly(vinyl chloride) (PVC) and poly[(vinyl chloride)‐co‐(vinyl acetate)] (poly(VC‐co‐VAc)) membranes were investigated for aqueous organic acid solutions by pervaporation and evapomeation. The PVC membrane preferentially incorporates organic acids and predominantly permeates water from aqueous organic acid solutions. Water permselectivities of these aqueous solutions through the PVC membrane are significantly dependent on high diffusivity of water across the membrane. It was found that the permeation rate increases and the separation factor for the water permselectivity decreases with increasing vinyl acetate (VAc) content in the poly(VC‐co‐VAc) membrane. Preferential solubility of acetic acid into the poly(VC‐co‐VAc) membrane increases with the VAc content. This result was explained by a strong affinity between acetic acid and the VAc unit in the poly(VC‐co‐VAc) membrane.
Molecular‐weight distribution in the activated‐monomer polymerization of ethylene oxide. Mechanistic implications
Authors: Szymanski Ryszard , Manolova Nevena , Rashkov Ilia 
Published: April 2003

AbstractThe mechanism of the activated‐monomer polymerization of ethylene oxide catalyzed by protic acids was investigated by means of an analysis of the molecular‐weight distribution curves from the polymers obtained. The results suggest that polymer ether groups participate in the polymerization by forming hydrogen‐bonded complexes and tertiary oxonium cations in the reaction with the activated monomer, both being intermediates of the propagation reactions.
Stereospecific polymerization of methylthiirane in homogeneous phase, 3. Study of the enantioasymmetric process
Authors: Boucard Valérie , Dumas Philippe , Sigwalt Pierre , Guérin Philippe 
Published: April 2003

AbstractEnantioasymmetry was studied for polymerizations of methylthiirane initiated by bis(isopropyl‐S‐cysteinato)cadmium and run in bulk. The ratio of rates of consumption of the two antipodes is independent of their concentrations. The enantioasymmetric constant kR, measuring the preferential choice of the R‐antipode, is depending on both the relative number of the two types of active sites and on their reactivities. An effect on enantioasymmetry of the molecular weight of the growing chains bearing the active sites, is occurring with two distinct stages: The first one is observed, with an enantioasymmetric constant kR = 1,5, from the appearance of stereospecificity up to molecular weights of 35000 (for the main chain) and the second one with kR = 1,07 for molecular weights higher than 35000. In the first stage, the cysteinato end group of the oligomer chain remains linked to cadmium (by cadmium‐nitrogen complexation) and the two active sites are diastereoisomers having different reactivities. In the second stage, the macrocyclic oligomer becomes too large and cadmium‐nitrogen interaction is suppressed. The active sites are now enantiomers having the same reactivity. In this case, enantioasymmetry depends only on the unbalance between the amounts of the two types of active sites. The maximum size the macrocyclic oligomer can reach depends on the initiator concentration.
Comb‐like methacrylamide polymers containing condensates of amino acids and azobenzene moieties in the side chains
Authors: Niemann Manfred , Ritter Helmut 
Published: April 2003

AbstractThe synthesis and free‐radical polymerization of 4‐(6‐methacryloylaminohexanoylamino)azobenzene (4), 4‐(11‐methacryloylaminoundecanoylamino)azobenzene (5), and 4‐[11‐(11‐methacryloylaminoundecanoylamino)undecanolyamino]azobenzene (6), are described. The monomers; the corresponding homopolymers 8–10, poly(4‐methacryloylaminoazobenzene) (7), and copolymers of 5 with stearyl acrylate, 11, and methyl methacrylate, 12, were characterized by DSC and TG analysis. Homopolymers with relatively long amino acid spacer groups were crystalline, the copolymer 12 was not crystalline. The UV‐induced E/Z photoisomerization and the thermal back‐isomerization were investigated for some of the monomers and polymers in solution and in solid films and correlated with the structures of the compounds. After photoisomerization the crystallinity of homopolymer 9 vanished because of disordering of the azobenzene side chains.
Synthesis of telechelics with furanyl end‐groups by radical polymerisation with azo‐initiators and network formation with unsaturated polyesters via Diels‐Alder additions
Authors: Edelmann Dirk , Ritter Helmut 
Published: April 2003

AbstractNew azo‐initiators with two and four furanyl groups were prepared: N,N′,N″,N″′‐Tetrafurfuryl 2,2′‐azo‐2,2′‐dimethyldiglutaramide (2), tetrakis[2‐(2‐furoyloxy)ethyl] 2,2′‐azo‐2,2′‐dimethyldiglutarate (4), bis[2‐(2‐furoyloxy)ethyl] 2,2′‐azodiisobutyrate (6), and N,N′‐difurfuryl‐2,2′‐azodiisobutyramide (9). The decay constants and the activation energies of the decomposition of the azo compounds were measured by thermogravimetric analysis. Radical polymerisations of styrene and some (meth)acrylates were performed under “dead‐end” conditions. The telechelic oligomers were characterized by GPC and NMR spectroscopy, proving a furanyl functionality of nearly two or four. The kinetics of Diels‐Alder reactions between the telechelics and the dienophils maleic anhydride and dimethyl maleate were measured under pseudo‐first order conditions. Addition of the telechelics to an unsaturated polyester prepared from maleic anhydride and diols led to a solid material with network structure.
LC‐polyimides, 10. Poly(ester‐imide)s derived from pyromellitic dianhydride and ω‐amino acids and various diphenols or α,ω‐diols
Authors: Kricheldorf Hans R. , Pakull Ralf , Schwarz Gert 
Published: April 2003

AbstractSix dicarboxylic acids were prepared from pyromellitic dianhydride and ω‐amino acids, such as glycine, 4‐aminobutyric acid, 5‐aminopentanoic acid, 6‐aminohexanoic acid, 11‐aminoundecanoic acid and 12‐aminododecanoic acid. Polyesters were prepared from these dicarboxylic acids and 4,4′‐biphenyldiol, 2,6‐dihydroxynaphthalene, 2,7‐dihydroxynaphthalene, methyl‐, chloro‐and phenylhydroquinone. All polyesters were characterized by elemental analyses, viscosity and differential scanning calorimetry (DSC) measurements, and by optical microscopy. Several polyesters were also characterized by wide‐angle X‐ray scattering (WAXS) powder patterns, by penetration measurements and thermogravimetrical analyses. Those polyesters derived from highly symmetrical diphenols and diols are highly crystalline (>90%) and form a layer structure in the solid state. An amorphous phase was not detectable and the heat distortion temperature corresponds to the melting point. Poly(ester‐imide)s derived from less symmetric diphenols are semicrystalline and glass transition temperatures are detectable. However, true liquid‐crystalline phases were never found.
New polyurethane compositions containing high amounts of covalently bonded heparin
Authors: Marconi Walter , Barontini Paolo , Martinelli Andrea , Piozzi Antonella 
Published: April 2003

AbstractHeparin was bonded covalently to hydrophilic polyurethanes. Polymers were characterized by spectroscopic techniques (IR and 1H, 13C NMR), molecular weight measurements and differential scanning calorimetry. The heparin content of the polymer films (up to more than 500 μg/cm2) was determined by a calorimetric system, and its biological activity was evaluated in vitro by APTT (activated partial thromboplastin time) measurements with a tenfold increase of the clotting time (about 300 s) with respect to the clotting time of human plasma (30 s). When heparin is bonded to a polymer provided with a hydrophilic polyfunctional spacer, the heparin content of the films is remarkably higher than previously described (about twice the reported values), and also the biological activity of the bonded heparin is favourably affected.
Poly(arylene)s containing structural units derived from the 1,2‐diketo building block
Authors: Chmil Knut , Scherf Ullrich 
Published: April 2003

Abstract1,2‐Diketones may serve as starting materials for various carbo‐ or heterocyclic organic compounds. Two different synthetic routes towards poly(arylene)s containing structural units derived from the 1,2‐diketo building block are presented. The first route involves the generation of polymeric 1,2‐diketones via aryl‐aryl coupling, followed by polymer‐analogous derivatisation. The second synthetic sequence includes formation of the 1,2‐diketo derivatives on the stage of monomeric compounds and subsequent polycondensation of these monomers. In this manner, aromatic polymers possessing the quinoxaline, 1,2,4‐triazine and tetraphenylcyclopentadienone subunits are available. The polymeric 1,2,4‐triazines are particularly attractive because they offer the possibility of a thermal conversion into polymers containing the diphenylacetylene building block.
Application de la spectrométrie mécanique et diélectrique à i'analyse du comportement du poly(téréphtalate d'éthylène). Influence de la cristallinité
Authors: Gauthier Catherine , Chailan Jean‐François , Chauchard Jacques 
Published: April 2003

AbstractIn order to correlate crystallinity and dynamic mechanical properties, poly(ethylene terephthalate) (PETP) samples were prepared and subjected to viscoelastic measurements. The evolution of the glass‐rubber transition is analyzed for samples annealed at different temperatures. Multiplexing analysis allows to draw the Cole‐Cole plot and to develop a rheological model for the polymer behaviour. In the case of the amorphous PETP, the asymmetric Cole‐Cole plot may be represented by a “biparabolic” rheological model. On the other hand, for the semi‐crystalline polymer, the Cole‐Cole plot is symmetrical and the corresponding rheological model is the “liquid Cole” one. Dielectric spectroscopy experiments are in good agreement with the previous method. Particularly, the Cole‐Cole plot for semi‐crystalline samples is perfectly symmetric. The previous rheological models with, in addition, a static modulus are applicable to glass‐fibre reinforced PETP. These new models are called “limited biparabolic” and “Zener parabolic” model, respectively.
Synthesis of photocrosslinkable polysulfones containing 2,6‐distyrylpyridinium units and preparation of membranes for water‐ethanol separation
Authors: Koch Thomas , Ritter Helmut 
Published: April 2003

AbstractSeveral unsaturated photoreactive polysulfones were synthesized by polycondensation of different amounts of 4,4′‐[pyridine‐2,6‐diylbis(vinylene)]diphenol (1) and 4,4′‐(isopropylidene)diphenol (2) with bis(4‐chlorophenyl) sulfone (3). Non‐uniform photoreactions were observed during UV‐irradiation, by kinetic measurements. (2+2)‐Cycloaddition of the styrylpyridinium vinyl groups as a main reaction leads to a network structure. The amorphos polycondensates were cast from CHCl3 solution to produced symmetric membranes, and the significant influence of the chemical structure and the UV‐irradiation on the permselectivity of the membranes towards water/ethanol was proved. A preferred permeation of water was observed in all cases.
Effects of matrix charges on the electrochromic behavior and degradation of polyaniline in its composite film with polyion complexes
Authors: Morita Mitsuyuki 
Published: April 2003

AbstractEffects of charge balance were investigated of cationic and anionic groups, contained in a matrix polymer, on the electrochromic behavior and electrochemical degradation of polyaniline in its composite film with the matrix polymer, in contact with a non‐aqueous aprotic medium. Polyion complexes prepared with different weight ratios of poly(sodium 4‐styrenesulfonate) and poly(allylamine hydrochloride) were employed as the matrix polymer containing a controlled ratio of cationic and anionic charges. From in situ visible and ex situ FT‐IR spectroscopy of the polyaniline‐polyion complex composite films in different oxidized states, it is found that appropriate charge balances in the matrix polymer provide large electrochromic changes and high electrochemical stability of the polyaniline in the matrix. The redox process of polyaniline in aprotic media and the effect of the matrix charge balance on the process are also discussed.
Polymerizable tautomers, 9. Tautomerism and polymerization of vinyl acetoacetate
Authors: Masuda Seizo , Tanaka Masami , Asahi Yutaka 
Published: April 2003

AbstractThe keto/enol tautomeric constants of vinyl acetoacetate (1) were determined in various solvents. The tautomeric constants are significantly affected by the solvents, and the ketonic form is predominant in polar solvents. Regression analysis of the tautomeric constants with solvatochromic parameters gives a good linear correlation, taking into account, as major factors, polarity and hydrogen bond acceptor basicity of the solvent. The equilibria depend also on concentration and temperature. Copolymerization of 1 (M1) and styrene (M2) was carried out in benzene and acetonitrile. Monomer reactivity ratios were obtained as r1 = 0,08 and r2 = 9,36 in benzene, and r1 = 0,07 and r2 = 9,88 in acetonitrile. Q and e values of 1 were calculated to be 0,069 and −0,26 for copolymerization in benzene, and 0,062 and −0,19 for that in acetonitrile. Thus, the polymerization and copolymerization of 1 are not influenced by the solvents.
Formation of supermolecular structures of polysaccharide‐surfactant complexes in aqueous solutions. Influence of the polymer backbone
Authors: Aust Nicolai , Zugenmaier Peter 
Published: April 2003

AbstractNovel water‐soluble derivatives of cellulose, amylose and dextran are synthesized and investigated with regard to their special interactions with the anionic surfactant sodium dodecylsulfate (SDS) by means of rheological flow‐ and oscillatory measurements as well as electrolytic conductivity in aqueous solution. The derivatives of amylose and dextran show a continuous adsorption of SDS with increasing surfactant concentration leading to an increase of the viscosity and of the viscous part of the shear modulus of the solution. Only low elastic parts are detectable. In contrast, the behaviour of cellulose derivatives differs extremely with increasing amount of SDS. The viscosity and the elastic part of the shear modulus of aqueous solutions reach a well pronounced maximum and then drop almost to the initial values. A similar behaviour is also observed by adding the cationic surfactant hexadecyltrimethylammonium bromide. It is concluded that the observed differences in properties of the cellulose derivatives on the one side and derivatives of amylose and dextran on the other are cause by the structure of the polymer main chain, because the side groups for all of these polymers are comparable.
Spontaneous polymerization of amphiphilic vinyl monomers, 3. Further studies on spontaneous polymerization of sodium alkyl 2‐hydroxy‐3‐methacryloyloxypropyl phosphates in micellar and reverse micellar systems
Authors: Yasuda Yutaka , Rindo Katsuhiko , Tsushima Rikio , Aoki Shuzo 
Published: April 2003

AbstractAddition of sodium chloride and some surface active agents to the micellar or reverse‐micellar solution of sodium alkyl 2‐hydroxy‐3‐methacryloyloxypropyl phosphates (Cn‐AHMP) surprisingly changed the ability of spontaneous polymerization. Low‐reactive C8AHMP in water became spontaneously polymerizable upon addition of NaCl to achieve a conversion of ca. 100%, and the non‐reactive C16‐AHMP turned out to be highly reactive upon addition of an equimolar amount of sodium dodecyl glyceryl phosphate in water and in benzene. On the other hand, the high reactivity of C12‐AHMP decreased upon addition of the surfactants. These results indicate that the additives modify the monomer aggregation state, and that there is a state of aggregation that is most suitable to generate the initiating radical species. The NMR measurement of the proton spin relaxation time gave important information on the aggregation state. In the spontaneous copolymerization of C12‐ and C14‐AHMP in water, the total conversion decreased with increasing feed content of the C14 monomer, but the residual monomer ratios were equal to the initial ones. ESR spectra were detected directly in the spontaneous polymerization system of C12‐AHMP in both water and benzene. The polymerization of C16‐AHMP initiated with a pre‐polymerized solution of C12‐AHMP showed that some portion of the polymer radicals remained active for 2 − 3 h at room temperature, after the first‐stage polymerization of C12‐AHMP was complete.
High mileage catalysts for olefin polymerization, 34. Methanolysis of titanium, vanadium and chromium olefin polymerization catalysts
Authors: Nazaki Takashi , Chien James C. W. 
Published: April 2003

Abstract14CH3O3H was used to quench ethylene polymerization by transition metal catalysts. 3H labeling occurred exclusively for Ti‐containing catalysts, whereas more than 95% of the chains were labeled with 14CH3 for the Cr‐containing catalysts. Both modes of labeling occurred with V‐containing catalysts. The observed phenomena indicate a change of “coordinate‐carbanionic” to “coordinate‐carbocationic” character for the alkyls of Ti, V and Cr in this order.
Complexation of sodium cations by polymeric esters of phosphoric acid
Authors: Szymanski Ryszard , Penczek Stanislaw 
Published: April 2003

AbstractThe complexation of sodium tetraphenylborate by poly(2‐methoxy‐2‐oxo‐1,3,2‐dioxaphospholane) and by poly(2‐methoxy‐2‐oxo‐1,3,2‐dioxaphosphorinane) in methanol solutions was studied using a previously derived relationship between solution composition and the width of a 23Na NMR signal. The results indicate that the equilibrium constants of complexation of sodium cations by both phosphoric‐ester polymers are of the same order of magnitude as the corresponding equilibrium constants of complexation of sodium cations by poly(oxyethylene).