bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymeric phthalocyanines and their precursors, 8. Synthesis and analytical characterization of polymers from 1,2,4,5‐benzenetetracarbonitrile
Authors: Wöhrle Dieter , Marose Ulrich , Knoop Renate 
Published: April 2003

AbstractPolymers 3 were prepared by reaction of 1,2,4,5‐benzenetetracarbonitrile (2) or 2,3,9,10,16,17,23,24‐(29H, 31H)‐phthalocyanineoctacarbonitrile (5a) with various metal salts or metals. The polymer structures were investigated by comparing their IR and UV/VIS spectra with those of 5. Structurally uniform polymeric phthalocyanines 3 with a number of phthalocyanine units Pc ⩾ 8, containing only nitrile end groups, were obtained from 2 or 5a with various copper salts. By saponification of 3 polymers (Pc ⩾ 3) with carboxylic acid end groups were obtained. The reactions of 2 or 5a with other metal salts or metals yielded polymers of varying structural uniformity. Metal free 3a was also synthesized.
Moisture‐curable rubbers, 3. Moisture‐cure of chlorosulfonated polyethylene
Authors: Yamada Akira , Shiokaramatsu Yoshiyuki , Yamashita Shinzo 
Published: April 2003

AbstractChlorosulfonated polyethylene (CSM) was grafted with 3‐aminopropyltriethoxysilane (APS) and the product was cured by exposing to moisture and by using dibutyltin dilaurate (DBTDL) as catalyst for condensation. The moisture‐cured product showed a tensile strength of 7,8 MPa when the amount of APS added was 0,5 equivalent to the amount of chlorosulfonyl groups. The rate constant of the reaction of CSM with APS was found to be 8,5 · 10−2 l · mol−1 · s−1 at 100°C in toluene, which is 850 times higher than that of the reaction of chlorinated butyl rubber with APS. The activation energy and the frequency factor of the reaction were 89 kJ · mol−1 and 2,0 · 1011 l · mol−1 · s−1, respectively. The activation energy of the moisture‐cure of APS‐grafted CSM was determined to be 44 kJ · mol−1.
Heparinizable materials, 5. Preparation and FTIR characterization of polyurethane surfaces grafted with heparin‐complexing poly(amido‐amine) chains
Authors: Barbucci Rolando , Benvenuti Manuela , Casini Giuliana , Ferruti Paolo , Nocentini Mila 
Published: April 2003

AbstractThe chains of poly(amido‐amine) (1) were grafted on the surface of two different polyurethanes (2 and 3), one of which being a commercial product. All the chemical steps of the grafting reaction were monitored by chemical analysis and FTIR spectroscopy. The poly(amido‐amine) was found to be able to form a complex with heparin by electrostatic interaction. The heparin can be totally removed by using a 0,1 M NaOH solution. The heparin adsorbing capacity of the two resulting materials was biologically tested. A constant heparin/poly(amido‐amine) ratio, observed for both polyurethane samples, leads to the assumption that the complex formation reaction proceeds via a defined stoichiometry.
Model glycoconjugates consisting of biantennary N‐glycans coupled to fatty acids: Synthesis and X‐ray diffraction study
Authors: Michel Véronique , Gallot Bernard 
Published: April 2003

AbstractIsolated glycopeptides of the N‐acetyllactosaminic type, typically present on cell surface membranes, were linked through their NH2‐terminus to activated palmitic acid. The method used was quantitative for negatively charges glycans and for neutral glycans. The liposaccharides thus obtained adopt, in concentrated water solutions, mesomorphic structures which were studied by X‐ray diffraction analysis. The comportment of charged and uncharged liposaccharides was compared.
Liposaccharides with a saccharidic chain of hen ovotransferrin: Synthesis, determination of the mesomorphic structure, and comparison with other liposaccharides
Authors: Santarelli Xavier , Douy André , Gallot Bernard 
Published: April 2003

AbstractThe amphipathic liposaccharide OT 16 was synthesized by coupling activated palmitic acid with the terminal asparagine residue of the glyco‐amino acid from hen ovotransferrin that contains only mannose and N‐acetylglucosamine residues. X‐ray diffraction showed that the liposaccharide OT 16 exhibits a liquid crystalline structure in concentrated water solution and in the dry state. This cubic structure is compared with the structure of other liposaccharides previously synthesized in order to establish the influence of the nature of the saccharidic chains on the liquid crystalline structures exhibited by amphipathic liposaccharides.
Electric field effects on a liquid‐crystalline side chain polymer with a negative dielectric anisotropy
Authors: Goozner Robert E. , Finkelmann Heino 
Published: April 2003

AbstractThe behavior of methacrylic side chain polymers in an electric field was observed for a homopolymer (1) exhibiting a negative dielectric anisotropy compared with a copolymer (2) of positive dielectric anisotropy. Homopolymer 1 orients spontaneously homeotropic and thus enables the determination of the threshold voltage, rise time and decay time. Based on these experimental results the bend elastic constant and viscosity coefficient were estimated using literature values for the dielectric anisotropy. With respect to the bend elastic constant and electrohydrodynamic effects (e.g. Williams Domains) the homopolymer behaves similarly to low‐molar‐mass liquid crystals, while owing to the high viscosity coefficient response times are large in magnitude.
Electrosynthesis of poly(1,4‐phenylene) catalyzed by nickel complexes
Authors: Fauvarque Jean‐François , Digua Abdelouafi , Petit Michel‐Alain , Savard Jacques 
Published: April 2003

AbstractConjugated polymers were prepared by electroreduction of aryl dihalides in presence of nickel complexes as catalysts. For instance, poly(1,4‐phenylene) was obtained from 4,4′‐dibromobiphenyl in high yield (85%). According to the coupling mechanism and to IR spectra, the chains of the polymer are expected to have regular para‐linkages and an average length ranging from 6 to 18 phenylene units. The effects of temperature, nature of monomer, catalyst and electrolyte on the yields and on the properties of the polymer were explored.
Re‐investigation of the 4‐nitrophenyl chloroformate activation of dextran. Evidence for the formation of different types of carbonate moieties
Authors: Vandoorne Filip , Vercauteren Ronny , Permentier Dirk , Schacht Etienne 
Published: April 2003

AbstractDextran was activated by reaction with 4‐nitrophenyl chloroformate. Analysis of the total carbonate content and the content of 4‐nitrophenyl carbonate moieties during the course of the reaction demonstrate the formation of different types of carbonate moieties. The 4‐nitrophenyl carbonate moieties are transformed into other carbonate structures most likely by reaction with neighbouring polymeric hydroxyls. This process is strongly enhanced by addition of a strong base.
Polymer‐supported bases, 4. Macrolide synthesis from ω‐bromocarboxylic acids using polymer‐supported 1,8‐diazabicyclo[5.4.0]undec‐7‐ene
Authors: Tomoi Masao , Watanabe Takashi , Suzuki Takayuki , Kakiuchi Hiroshi 
Published: April 2003

AbstractThe macrolactonization of ω‐bromocarboxylic acids was carried out in the presence of polystyrene‐supported 1,8‐diazabicyclo[5.4.0]undec‐7‐ene. The macrolide yield was found to be a function of the degree of ring substitution and of crosslinking, which governs the effective concentration of the fixed substrate within the polymeric reagent. The effect of the polystyrene matrix on the macrolide yield in the heterogeneous system was discussed by comparison with the corresponding homogeneous reaction.
Polymerisationsauslösung mit substituierten ethanen, 7. Zum mechanismus des oligomer‐starts
Authors: Błedzki Andrzej , Braun Dietrich , Tretner Hartmut 
Published: April 2003

AbstractMethyl methacrylate (MMA) oligomers, obtained by radical polymerization of MMA with substituted 1,1,2,2‐tetraphenylethanes, contain one unstable C‐C bond which can be cleaved thermally under common polymerization conditions. This was shown by means of gel permeation chromatography, field desorption mass spectrometry and model compounds.
Reactivity of hydroxyl groups in cellulose towards chlorotri(p‐tolyl)methane
Authors: Jain Rajesh K. , Agnish Shadi Lal , Lal Krishan , Bhatnagar Hari L. 
Published: April 2003

AbstractThe reactivity of primary and secondary hydroxyl groups of cellulose towards chlorotri(p‐tolyl)methane in pyridine was studied in the temperature range of 60 to 100°C. The rate of reaction with the primary hydroxyl groups was found to be 43 times faster than that with the secondary hydroxyl groups of cellulose. The kinetic data showed that the reactivity of chlorotri(p‐tolyl)methane towards primary hydroxyl groups of cellulose is higher than that of chlorotriphenylmethane (trityl chloride). The energies of activation for the reaction of primary and secondary hydroxyl groups of cellulose with chlorotri(p‐tolyl)methane were found to be 39,6 and 43,1 kJ · mol−1, respectively. The reaction was observed to be pseudo first order.
A new convenient synthesis of ortho‐, meta‐ and para‐chloromethylstyrenes
Authors: Monthéard Jean‐Pierre , Camps Marcel , Chatzopoulos Michel , Pham Quang‐Tho 
Published: April 2003

AbstractOrtho‐, meta‐ and para‐chloromethylstyrenes (4a – c) were prepared by a three‐step sequence starting from the commercial ortho‐, meta‐ and para‐bromobenzyl bromides (1a – c), which were transformed into the methoxymethyl derivatives (2a – c). Coupling of the corresponding Grignard compounds with vinylbromide in presence of a transition metal catalyst led to the methoxymethyl styrenes (3a – c), which were transformed into the desired products by reaction with BCl3. IR, 1H and 13C NMR spectra of the 3 isomers were studied.
Dilute solution properties of poly(allylammonium chloride) in aqueous sodium chloride solutions
Authors: Ochiai Hiroshi , Handa Miho , Matsumoto Hiromi , Moriga Toshinori , Murakami Ichiro 
Published: April 2003

AbstractTen fractions of poly(allylammonium chloride) were investigated at 25°C in sodium chloride solutions of various concentrations, cs, by viscosity and light scattering techniques. The molecular weight (Mw)‐intrinsic viscosity [η] relationships were established at four NaCl concentrations. The unperturbed dimensions estimated from the Stockmayer‐Fixman plot are independent of cs. The second virial coefficient A2 and the excluded volume parameter B as well as [η] were found to be proportional to c and to have negative values in the limit of infinite cs. In addition, it was found that the electrostatic part of the expansion factor can be expressed in terms of a reduced parameter (Mw/cs)1/2 in a fairly wide range of Mw and cs.
Ring‐opening polymerization with kinetically controlled enhancement of macrocyclic oligomers or linear macromolecules
Authors: Słomkowski Stanisław 
Published: April 2003

AbstractThe equilibrium and the kinetics of the ring‐opening polymerization accompanied with backbiting and end‐to‐end ring closure are analyzed using computer simulation. The influence of monomer ring strain and competition between back‐biting and end‐biting on the overall kinetic process is evaluated. The results of calculations are compared with examples from the ionic ring opening polymerization of heterocyclic monomers. It is established that in the polymerization of nonstrained monomers fast end‐biting manifests itself by an induction period. In the absence of end‐biting the polymerization of strained monomers yields a system in which the polymer concentration is temporarily higher than at equilibrium (kinetic enhancement in polymer). On the other hand, very fast end‐biting, hindered only in the case of the monomeric species by the ring strain, results in concentrations of the macrocyclics which are transitorily higher than the corresponding equilibrium concentrations (kinetic enhancement of macrocycles). The polymer synthesis with kinetically controlled concentration of cyclics is indicated.
Influence of an external magnetic field on the cross‐linking reaction of 1,4‐polybutadiene with bis(2,4‐dichlorobenzoyl) peroxide
Authors: Martl Michael G. , Schaller Raimund , Hummel Klaus 
Published: April 2003

AbstractThe cross‐linking of (Z)‐1,4‐polybutadiene with bis(2,4‐dichlorobenzoyl) peroxide was investigated between 80 and 100°C under the influence of an external magnetic field (flux density: 1 Tesla) and also without magnetic field. The cross‐linking density was determined by measuring the equilibrium swelling in toluene at 25°C. The statistical evaluation showed that the magnetic field causes a decrease in the cross‐link density. No influence of the magnetic field on the kinetics of the reaction was observed. The results are discussed in terms of the radical pair theory.
Synthesis of novel ordered poly(ester‐amide)s
Authors: Gopal Jayalakshmi , Srinivasan Mahalingam 
Published: April 2003

AbstractFive different completely aromatic, ordered poly(ester‐amide)s 6a — e were prepared from diphenols 5 and 4,4′‐carbonyliminodibenzoyl dichloride (3). This bifunctional “amide‐acid chloride” was synthesized in two steps by oxidation of 4,4′‐dimethylbenzanilide (1) with permanganate under neutral conditions and subsequent reaction with thionyl chloride. The polymers obtained were characterized by IR spectroscopy and viscosity measurements. Their physical properties like density, solubility, and thermal behaviour were also studied.
Polymers with tertiary amino groups obtained by the reaction between chloromethylated polystyrene and 3‐alkylaminopropionitrile
Authors: Drǎgan Stela , Bǎrboiu Virgil , Csergö Doina , Petrariu Ioan , Dima Mihai 
Published: April 2003

AbstractPolymers with tertiary amino groups were obtained by reaction of chloromethylated polystyrene (CMPS) with 3‐alkylaminopropionitriles (2a — e). The resulting polymers 3a — e were characterized by elemental analyses, IR and 1H NMR spectra. Kinetic investigation showed that the reaction is characterized by two rate constants, the rate change taking place at a conversion of 45–50%. Viscosimetric studies of the hydrochlorides of polymers 3a — e in water and methanol showed that they behave as polyelectrolytes only in methanol. The abnormal behaviour of water solutions was explained by hydrolysis reaction. To prove the conclusions on the molecular structures of 3a — e and the reactivity of CMPS, a study of the reaction of benzyl chloride with the same amines was performed.
Soluble poly(divinylbenzene): Reaction mechanism for the anionic polymerization of divinylbenzene with lithium diisopropylamide as catalyst
Authors: Nagasaki Yukio , Ito Hiromi , Tsuruta Teiji 
Published: April 2003

AbstractThis paper presents results of the studies on the mechanism of initiation, propagation and chain transfer reactions in the recently found polymerization of 1,4‐ and/or 1,3‐divinylbenzene (DVB), initiated with lithium diisopropylamide/diisopropylamine. Initiation was confirmed to take place by addition reaction of the alkylamino group to the DVB molecule. The population of the triad tacticity of the soluble poly(DVB) suggested the steric course of the polymerization to proceed according to Bernoullian statistics with respect to the diad placements, m and r. The chain transfer reaction was found to take place via the free amine, the chain transfer reactivity of a primary amine being higher than that of a secondary amine. Comparative studies on the reactivity and selectivity of sodium diisopropylamide toward styrene and DVB were also carried out with respect to lithium diisopropylamide as reference.
Anionische polymerisation von ω‐isocyanatocarbonsäuretrialkylsilylestern
Authors: Mormann Werner , Schwabe Annelene , Sikora Regina 
Published: April 2003

Abstractω‐Isocyanatopropionic and ‐butyric acid trialkylsilyl esters are converted to polyisocyanates by means of anionic polymerisation. Polymeranalogous reactions (hydrolysis, transesterification) of the silyl ester groups are possible though being limited by the occurrence of depolymerisation at elevated temperatures.
Properties of ring‐shaped polymer coils. Theoretical calculation and experimental determination of hydrodynamic parameters for ring‐shaped and linear polymer coils
Authors: Huang Jiaxian , Li Chunroung , He Binglin 
Published: April 2003

AbstractBased on the ratio between the intrinsic viscosities of ring‐shaped and linear polymers [η](R)/[η](L), the relationships are deduced between the corresponding equivalent radii of coils req.(R)/req.(L), sedimentation coefficients at zero concentration S0(R)/S0(L), diffusion coefficients at zero concentration D0(R)/D0(L), friction coefficients F(R)/F(L), molecular weights from Svedberg's equation MSD(R)/MSD(L), and Flory‐Krigbaum‐Mandelkern‐Scheraga invariant β(R)/β(L). The experimental verification has been conducted with ring‐shaped polystyrene samples obtained by anionic polymerization of styrene with sodium naphthalene (sodium dihydronaphthylide) according to the multistep reaction of Hild, Kohler and Rempp.
Preferential adsorption of swollen polydimethylsiloxane (PDMS) networks and of linear PDMS in 2‐butanone/cyclohexane
Authors: Masegosa Rosa M. , Gómez‐Antón M. Rosa , Horta Arturo 
Published: April 2003

AbstractMeasurements of preferential adsorption, λ(ν), by differential refractometry, and of swelling equilibrium, ν3−, of polydimethylsiloxane (PDMS) networks were carried out in the solvent mixture ethyl methyl ketone (MEK) + cyclohexane (Ch), at 25°C. The preferential adsorption and the total sorption were also determined, by light scattering, for linear PDMS in the same mixed solvent. The behaviour of the system crosslinked PDMS/MEK + Ch is compared with that of the system linear PDMS (dilute solution)/MEK + Ch. The experimental values of ν3and λ are compared with those predicted by thermodynamic theory. For this comparison, new thermodynamic equations, to calculate preferential and total sorption at finite polymer concentration, are derived using the extended Flory‐Huggins model. The derived equations take into account the solvent composition dependence of interaction parameters, neglected (as an approximation) in previous works.
Polymer crystallinity and morphology in polysiloxanes. poly(tetramethyl‐p‐silphenylenesiloxane) and poly(tetramethyl‐p‐silphenylene/dimethylsiloxane) copolymers
Authors: Magill Joseph H. 
Published: April 2003

AbstractThe crystallinities of polysiloxane homo‐ and copolymers, measured by DSC and checked by X‐ray measurements, are presented. A wide range of crystallization conditions and molecular weight fractions were investigated. The morphological implications of crystallinity changes as a function of molecular weight are discussed in regard to other physical parameters. It is concluded that the dependence of crystallinity and X‐ray long period on molecular weight is in accord with a defect interface created via chain entanglements primarily, which are trapped during crystallization. The morphology of the specimens directly reflects their preparative history and molecular weight.
New phospholiposaccharides as model glycoconjugates. Synthesis and structural study
Authors: Santarelli Xavier , Douy André , Gallot Bernard 
Published: April 2003

AbstractNew phospholiposaccharides OT‐6‐DPPE and OT‐2‐DPPE were synthesized by linking the α‐amino function of the asparagine residue of the glyco‐amino acid OT from hen ovotransferrin (that contains only Man and ClcNAc residues) to the primary amino group of the polar head of 1,2‐dipalmitoylphosphatidylethanolamine (DPPE) via a suberoyl or a succinoyl bridge. The structural study by X‐ray diffraction showed that the phospholiposaccharide OT‐6‐DPPE exhibits a lamellar structure in concentrated aqueous solution and in the dry state at room temperature; in this lamellar structure, the paraffinic chains are crystallized, hexagonally packed, and tilted as in the Lβ, structure of synthetic phospholipids, while the saccharidic chain adopts an “Y‐shaped conformation”, A comparison with the previously synthesized liposaccharide OT‐16, formed by the same glyco‐amino acid OT but linked to palmitic acid and exhibiting a cubic structure in which the saccharidic chain adopts a slightly deformed “T‐shaped conformation”, shows that it is possible to induce a conformational change of the saccharidic chain of hen ovotransferrin by changing the nature of the “hydrophobic moiety” linked to the saccharidic chain.
Interpenetrating polymer networks based on castor oil, 1
Authors: Patel Mayur , Patel Raman , Suthar Bhikhu 
Published: April 2003

AbstractLiquid prepolyesters (PPE) were obtained from castor oil and dibasic acids, viz. oxalic, malonic, succinic, glutaric, adipic, suberic and sebacic acids. All these prepolyesters were subsequently copolymerized with acrylamide by radical polymerization initiated with benzoyl peroxide. The resulting prepolyester (PPE)/polyacrylamide (PAm) interpenetrating polymer networks (IPN's) were characterized by elemental analyses, solubility behaviour, IR spectral study, differential scanning calorimetry and thermogravimetry. The transition behaviour was analyses for one IPN by the Ozawa and the Kissinger methods for calculating the various kinetic parameters.
Polymères porteurs de dérivés du glycérol, 5. Dérivés de la progestérone
Authors: Soutif Jean‐Claude , Ouchatar Lahcen , Couvret Denis , Brosse Jean‐Claude 
Published: April 2003

AbstractGlycerol was used as a very suitable compound to prepare reactive derivatives of aldehydes and ketones allowing reaction with polymerizable groups such as methacryloyl chloride. By radical polymerization of methacryloyl derivatives of acetals, synthesized from glycerol and progesterone or its models, polymers were obtained bearing on each constitutional unit a drug covalently linked by two types of bonds which can be cleaved by hydrolysis.
Studies on syntheses and permeabilities of special polymer membranes, 63 Active transport of adenine through cation exchange membranes with carboxyl groups
Authors: Uragami Tadashi , Moriyama Koichi , Yamamoto Makoto , Sugihara Mizuho 
Published: April 2003

AbstractWhen a cation exchange membrane, prepared from poly(isobutylene‐alt‐maleic anhydride) and poly(vinyl alcohol), is fixed in a diaphragm type cell with one side of the solution being adjusted to be alkaline and the other one acidic, a metal ion is always actively transported from the alkaline side to the acidic side, but adenine is actively transported in symport or antiport with metal ions. The transport mechanism of these metal ions and of adenine is discussed in detail.